JANSSEN EXHIBIT 2086
`
`Wockhardt v. Janssen lPR2016-01582
`
`JANSSEN EXHIBIT 2086
`Wockhardt v. Janssen IPR2016-01582
`
`

`

`PfZ'l”lCZ;Z7[es and Pmctice of
`ENDOCRINOLOGY
`
`AND
`METABOLISM
`
`THIRD EDITION
`
`J’
`
`V E
`
`DITOR
`Kenneth L. Becker
`
`ASSOCIATE EDITORS
`
`john P. Bilezikian
`William I. Bremner
`Wellington Hung
`C. Ronald Kahn
`
`D. Lynn Loriaux
`Eric S. Nylén
`Robert W. Rebar
`
`Gary L. Robertson
`Richard H. Snider, ]r.
`Leonard Wartofsky
`With 330 Contributors
`
`LIPl3lNCOTT WILLIAMS 8 \X/ILKINS
`
`' A Wolters Kluwer Company
`
`Philadelphia - Baltimore - New York - London
`Buenos Aires - Hong Kong;
`- Sydney .
`‘rokyo
`
`

`

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`Printed in the USA
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`
`Library of Congress Cataloging-in-Publication Data
`
`Principles and practice of endocrinology and metabolism / editor, Kenneth L. Becker;
`associate editors, John I’. Bile’/.ikian
`[et al.].--3rd ed.
`p. ;cm.
`lncludes bibliographical references and index.
`ISBN 0-7817-1750-7
`1. Endocrinology. 2. Lndocrine glands——Diseases. 3. Metabolisin--Disorders. l. Becker,
`Kenneth L.
`1. L’ndocrine Diseases. 2. Metabolic Diseases. WK 100 P957 2000]
`{l).\Jl-;\l:
`l{Cr'>~}t% .l’(>7 2000
`h l ti.4——clc2 l
`
`00-022095
`
`
`Care has been tal-;en to confirm the accuracy of the information presented and to
`describe generally accepted practices. However, the authors, editors, and publisher are
`not rysptjllhlblt’ for errors or omissions or for any consequences from application of the
`mformatioii in this bool; and make no warranty, expressed or implied, with respect to
`the currency, completeness, or accuracy of the contents of the publication. Application
`of this information in a particular situation remains the professional responsibility of
`the practitioner.
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`selection and dosage set forth in this text are in accordance with current recoininenda—
`tions and practice at the time of publication. However, in view of ongoing research,
`changes in government regulations, and the constant flow of information relating to
`drug therapy and drug reactions, the reader is urged to check the package insert for each
`drug for any change in indications and dosage and for added warnings and precautions.
`This is particularly important when the recommended agent is a new or infrequentlv
`employed drug.
`'
`Some drugs and medical devices presented in this publication have Food and Drug
`Administration (FDA) clearance for limited use in restricted research settings. It is the
`responsibility of health care providers to ascertain the l’l)A status of each drug or device
`planned for use in their clinical practice.
`
`1098765-1321
`
`

`

`704
`
`PARTV:THEADRENALGLANDS
`
`There is a close relationship between neural cells of the sympa-
`thetic ganglia and chromaffin cells. Small numbers of ganglion
`cells can be found in the adrenal medulla, and chromaffin cells
`occur in the sympathetic ganglia. Hence, neoplastic disorders
`affecting either cell type can arise throughout this system.
`The diagnosis of adrenal medullary hyperplasia depends on
`an increased volume of adrenal medulla in relation to the cor-
`tex. There is a diffuse nodular proliferation of normal medi1l-
`lary elements. This condition is seen mainly in families with
`multiple endocrine neoplasia type 2A and is considered a pre-
`neoplastic condition (see Chap. 188).
`_
`Neuroblastomas, ganglioneuroblastomas, and ganglioneuro-
`mas arise from neuroblasts. These tumors form a continuum from
`least to most differentiated and from malignant to benign. Neuro-
`blastoma usually is a tumor of infancy and childhood, with a
`median incidence at
`the age of 2 years.
`It originates in the
`paraganglia of the sympathetic nervous system or the adrenal
`medulla, and 60% arise in the abdomen. Grossly, it is a multi-
`nodular tumor with areas of hemorrhage, necrosis, and cystic
`degeneration?" The cells are arranged in nests and contam small,
`dark-staining nuclei with little cytoplasm. Although the light-
`microscopic features are not necessarily distinct from those of
`other childhood tumors, electron microscopic examination shows
`characteristic cytoplasmic neurosecretory granules. Neuroblasto-
`mas usually secrete catecholamines, their metabolites, or both.
`Characteristically,
`these tumors grow rapidly and rnetastasize
`early to local lymph nodes, the liver and other abdominal organs,
`and bone. Although spontaneous regression or differentiation into
`a more benign tumor may occur, mortality is high and treatment
`often includes combinations of palliative surgery, radiation, and
`chemotherapy.35 Ganglioneuroblastomas contain. some mature
`ganglion cells and have a better prognosis. Ganglionegirpmas are
`benign tumors arising from mature neuronal elements.~"'-7
`Pheochromocytomas arise from chromaffin cells. As expected
`from their cellular origin, 95% or more are in the abdomen, with
`most being in the adrenal glands?" Similar to chromaffin cells,
`however, they occasionally can be found anywhere along the sym-
`pathetic chain of ganglia from the base of the skull to the neck of
`the urinary bladder. Ten percent of patients with sporadic pheo-
`chromocytomas and 50% of those with familial pheochromocyto-
`mas have bilateral tumors. The pheochromocytoma that may occur
`in von Hippel-Lindau disease commonly is bilateral.3"3° Although
`only 5% to 10% are malignant, it is often impossible to distinguish
`benign from malignant neoplasms histologically. I’heochromocyto-
`mas are highly vascular tumors with local hemorrhage and cystic
`degeneration. Microscopically, they often have a chaotic pattern of
`pleomorphic elongated cells with prominent cytoplasmic granules
`(see Chap. 86). Although the light-microscopic features may not be
`diagnostic, electron microscopic examination demonstrates charac-
`teristic dense ca techolamine secretory granules.
`
`ADRENAL MEDULLARY HYPOFUNCTION
`
`The adrenal medulla is affected by the same systemic diseases
`_(tubercular and fungal infections, sarcoidosis, amyloidosis) as
`is the cortex and also is often the initial site of hemorrhage. Iso-
`lated adrenal medullary hypofunction is uncommon and usu-
`ally occurs in the setting of diffuse autonomic insufficiency.
`Sparse amounts of medullary tissue may be found in some eld-
`erly persons, but no specific abnormality has been described.
`
`REFERENCES
`
`. Neville AM, O'Hare M]. Histopathologv of the adrenal cortex. J Clin Endo-
`crinol Metab 1985; 14:791.
`7
`’
`
`. Neville AM, O’Hare MJ. The human adrenal cortex. Pathology and bio].
`ogy~an integrated approach. New York: Springer-Verlag, 1982,
`. Syrnington T. The adrenal cortex. In: Bloodworth IMB Jr, ed. Endocnng
`pathology. General and surgical. Baltimore: Williams & Wilkins, 19822419.
`. Gould VE, Sommers SC. Adrenal medulla and paraganglia. In: Bloodworth
`
`.
`
`JMB Ir, ed. Endocrine pathology. General and surgical. Baltimore; Williams
`& Wilkins, 1982:4735.
`. Francis IR, Cross MD, Shapiro B, et al. Integrated imaging of adrenal dis-
`ease. Radiology 1992; 184:1.
`. Breslow M]. Regulation of adrenal medullary and cortical blood flow. Am]
`I’hysiol 1992; 262:I'Il317.
`. Hornsby 1’). Regulation of adrenocortical function by control of growth
`and structure. In: Anderson DC, Winter 181), eds. Adrenal cortex: BIMR
`clinical endocrinology. Boston: Butterworth, 198521.
`In: D'Agata R,
`. Hyatt
`I’J. Functional significance of the adrenal zones.
`Chroiisos GI’, eds. Recent advances in adrenal regulation and function.
`New York: Raven I’ress, 1987235.
`In:
`. Winter JSD. Fiiiictional changes in the adrenal gland during life.
`D’Agata R, Chrousos CI’, eds. Recent advances in adrenal regulation and
`function. New York: Raven Press, 198751.
`. Copeland PM. The incidentally discovered adrenal mass. Ann Intern Med
`1983;918:940.
`. Doppman IL, Miller DL, Dryer A], et al. Macronodular adrenal hyperplasia
`in Cushing's disease. Radiology 1988; 1663347.
`. Carney IA, Young WF Ir. Primary pigmented nodular adrenocortical dis-
`ease and its associated conditions. The Endocrinologist 1992,‘ 2:6.
`. Ruder IIJ, Loriaux DL, Lipsett MB. Severe osteopenia in young adults asso—
`ciated with Cushing’s syndrome due to micronodular adrenal disease. J
`Clin Endocrinol Metab 197-1; 3911138.
`. Sakai Y, Yanase '1', Hara '1', et al. Mechanism of abnormal production of
`adrenal androgens in patients with adrenocortical admomas and carcino-
`mas. 1 Clin Endocrinol Metab 199-I; 78:36.
`. Del Gaudio A, Solidoro G. Myelolipoma of the adrenal gland: report of two
`cases with a review of the literature. Surgery 19861901293,
`. Kelley RI, Datta NS, Dobyns WB, et al. Neonatal adrenoleukodystrophy: new
`cases, biochemical studies, and differentiation from Zellweger and related
`peroxisomal polydystrophy syndromes. Am] Med Genet 1986; 23:869.
`. Schwartz RE, Stayer SA, Pasqiiariello CA, et al. Anesthesia for the patient
`with neonatal adrenoleukodystrophy. Can J Anaesth 1994; -11:56.
`I Xarli VI’, Steele AA, Davis I’), et al. Adrenal hemorrhage in the adult. Med-
`icine (Baltimore) 1978; 57:211.
`. Rao RII, Vagnucci AH, Aniico JA. Bilateral massive adrenal hemorrhage:
`early recognition and treatment. Ann Intern Med 1989; 110:227.
`, Cm-on ]>,Ch,,1,,,,1jCr MH, Cdmbus )1’, et al. Definitive adrenal insufficiency
`due to bilateral adrenal hemorrhage and primary antiphospholipid syn-
`d mine. J Clin Endocrinol Metab 1998; 8311437-
`I
`. Stolarc’/.ykk, Ruio SI, Smolyar D, et al. Twenty-four—hour urinary free cortisol in
`patients with acquired irnmunodeficiency syndrome. Metabolisin 1998; 47:690.
`. Verges B, Chavanet I’, Degres 1, et al. Adrenal function in HIV infected
`patients. Acta Endocrinol (Copenh) 1989; 1213633-
`. Bornstein SR, Gonzalez—Hernandez IA, Erhart~Bornstein M, et al. Intimate
`contact of chromaffin and cortical cells within the‘Iiuman‘adrenal gland
`forms the basis for important intraadrenal interactions. 1 Clin Endocrinol
`Metab 1991; 78:225.
`A
`A. Askin FB, Perlman El. Neuroblastoma and peripheral neuroectodermal
`tumors. Am J Clin I’athoI 1998; 1()9(4 Suppl IIIS3-7»
`_
`. Katzenstein HM, Cohn SL. Advances in the diagnosis and treatment of
`neuroblastoma. Curr Opin Oncol 1998; 1034-°§
`l_
`g
`. Schulman H, Laufer L, Barki Y, et al. Gmglinncurmm: an inmdciitaloina’
`of childhood. Eur Radiol 1998; 8:582.
`’
`)
`. Fujiwara '1', Kawamura M, Sasou S, Hirarnori K. Ixesults of surgery for a
`compound tumor consisting of pheochromocytoma and_ganglioneurobIas—
`toina in an adult; 5-year follow-up. Intern Med 2000; 39:38.
`. Meideiros LJ, Wolf BC, Balogh K, Federman M. A’drL‘I1fll(I’l10"<'l‘f"“‘0C)"
`toma: a clinicopathologic review of (>0 cases. I him I athol H89; 16:380.
`. Chew SL, Dacie JE, Reznik RH, et al. Bilateral pheochroinocytoinas in von
`Hippel-Lindau disease. Q] Med 1994) 57149
`I
`V
`_
`. Couch V, Lindor I IM, Karnes I’S, Michels VV. V011 ll'PP9H-'"d“” '~l'5C«l5C»
`Mayo Clin I’roc 2000,‘ 75:265.
`
`CHAPTER 72
`
`SYNTHESIS AND
`METABOLISM OF
`CORTICOSTEROIDS
`
`PERRIN C. WHITE
`
`The adrenal glands are e1icIocriii()lc)gi931lY _C"mPl°X "fgims that
`are composed of two distinct endocrine tissues derived from
`different embryologic sources] (see Chap. 71). The adrenal cor-
`tex (outer layer) constitutes 80% to 90% of the gland and is the
`
`

`

`Ch. 72: Synthesis and Metabolism of Corticosteroids
`
`705
`
`or
`
`A:B—trans
`
`A:B—cis
`
`(3
`
`9
`
`to B 87
`6
`
`FIGURE 72-2. Cis-trmis orientation of the steroid nucleus and location
`of the o.- and [3-substituents.
`
`BIOSYNTHESIS
`
`IMPORTATION INTO MITOCHONDRIA
`
`The rate-limiting step in steroid biosynthesis is importation of
`cholesterol from cellular stores to the matrix side of the mito-
`chondria inner membrane where the cholesterol side-chain
`
`cleavage system (CYP1'lA, adrenodoxin, adrenodoxin reduc-
`tase) is located. This is controlled by the stwoidogeiiic acute ragti-
`Inlory ].7l‘0lL’lI1
`(StAR),33“ the synthesis of which is increased
`within minutes by trophic stimuli such as adrenocorticotropic
`hormone (ACTH) or, in the zona glomerulosa, by increased
`intracellular calcium. StAR is synthesized as 21 37-l<Da phospho-
`protein that contains a mitochondrial importation signal pep-
`tide. However, importation into mitochondria is not necessary
`for StAR to stimulate steroidogenesis; to the contrary, the likeli-
`
`TABLE 72-1 .
`Adrenal Steroidogenesis: Nomenclature
`
`Nomenclature of the Major Naturally Occurring Steroid Hormones
`
`
`Bioclimiiicril NameC()l)lI1l()l1Nll1)1E Lotte,-T
`
`l’i‘egn-4-en— 1 l l3,2l—diol— l 8—al—3,20-
`dione
`
`I’regn-4—en-l‘l l3,2l—diol-3,20-dione
`l’regii-4-en—l 1 [3,'l7or.,2l—triol-3,20-
`dione
`
`I’regii—-l~en—1701,21-diol—3,11,20-trione
`Androst—5—en—3B-ol-17-one
`
`B
`1:
`
`E
`
`Aldosterone
`
`Corticosterone
`
`Cortisol (hydrocortisone)
`
`Cortisone
`
`Dehydroepiandrosterone
`(DHA, DHEA)
`Deoxycorticosterone (DOC)
`Deoxycortisol
`Estradiol
`
`l’regn—4-eii-2l-ol-3,20—dione
`l’i'egn-l-en-l7(1,2l-diol—3,20—di(me
`Estra-l,3,~l( l0)—ti‘ien-3,17[3—dio1
`l’rogesterone
`l’i‘egii-~l-en—3,Z0—dione
`And rost-~l—en- 1 7B-ol-3—one
`Testosterone
`
`
`0
`
`C21 Pregnane
`(Progesterone)
`
`C19 Androstane
`(Testosterone)
`
`C13 Estrane
`(Estradiol)
`
`FIGURE 72-1. The steroid nucleus. The four rings are labeled A, B, C, D,
`and the carbons are numbered as shown. Examples are shown of ster-
`oids from each of the three structural categories of steroid hormones:
`the 21-carbon pregnane derivatives, the 19-carbon androstane deriva-
`tives, and the 18-carbon estrane derivatives. '1 he names of the individ-
`ual steroids shown are indicated in parentheses.
`
`source of the steroid hormones, whereas the adrenal medulla is
`the source of catecholamines. Although the adrenal cortex and
`meduna are in close proximity, they f_unction independently.
`This chapter describes the biosynthesis, metabolism, mecha-
`nigms of action, and regulation of the steroid products of the
`adrenal cortex.
`Three major groups of hormones are produced by the adre-
`nal cortex; mi;iui'nlocorticoids, gliicacorticoids, and sex steroids.
`]\/linen-,]0c01-tjcojds are produced primarily by the zona glomer-
`ulosa; glucocorticoids are produced by the zona fascictilata;
`and sex Steroids originate primarily from the zona reticularis.
`The ho;-rmmal products of the adrenal cortex share cholesterol
`as a common precursor. Cholesterol is also the precursor for. the
`gonadal steroids, vitamin D and derivatives, and the bile acids.
`
`STRUCTURE AND NOMENCLATURE
`
`Stemids have a common structure with l7-carbon atoms
`C
`(.
`.
`.
`.m,mged in three six-inembered rings and a fourth five-
`membered 1.ing1abe1ed A, B, C, and D, respectively (Fig. 72-1).
`L
`E'ich of the 17 carbons is numbered in a standard way. Two
`‘
`7)
`.
`C
`3
`additional carbons, numbered 18 and 1), lflay
`attlagled at
`carbons .13 and .10, rC5peCtlV(3ly. Carbon atoms _ anc _ may
`C
`(.
`C
`.
`.
`.
`be qthched it the 17 position. These various additions yield
`three steroid families: the C18 (’sil‘IIl1L’S with an aromatic ring
`(estmgcns); the CW !llItl)‘()SifllIL’S (androgens); and tlple C31 prcgci
`_
`1
`‘
`-
`~
`4'
`_
`)
`*
`-
`'
`H(IH(’S (corticoids and pf08e5tm5) (5%
`72 1)‘ K élelol
`\
`(
`-
`‘
`nucleus lies in 1 plane that can be modified by the addition of
`substituents either above or below (P18 72'2)' The °l‘5”l’5m"‘
`,.,,tq(,,.C”,.1,,:[(,u, my plane (indicated by dotted lines in Fig. 72-2)
`ml th‘ B si1lis'ti'ti1i'iii‘s lie iilmvc’ Hit’
`l’l‘”"' lmdlcated by Solid
`it C, .)
`'12]
`,
`(Bud B rings may be attached so that the substitu-
`mtb ‘t K itizms 5 md 10 are in either the as or trails orienta-
`en s a pos
`<
`tions (see Fig. 72-2)-
`.
`.
`1
`.
`s
`A
`1t‘
`l'city of ll‘lUl{li and systciiintic or biodieiiiicnl names
`mu ipi
`(:30
`d 19.0 two
`»
`»
`_, ~.
`'1 Table 72-1). Between 1).
`an
`3 ,
`_
`“M for wch THOR‘ ~(
`( '
`)f Reichstein and of Kendall iso-
`groups under the diiection (
`_
`_
`E 1
`Y
`aturally occurring Sl:C'I‘O1ClS.. OC1 group
`lated most of the 11
`abetically in the order in which they were
`labeled steroids alph
`discovered with the result
`that
`the Same Compound was
`sometimes, given two different alphabetical designations.
`I
`Thus Kcndallg compound A is not the same as Reichstein’s
`compound A.
`
`

`

`706
`
`PART V: THE ADRENAL GLANDS
`
`3B-HSD
`
`CYP21
`CYI’11B‘l
`CYI’11B2
`CYP19
`HSDHB2
`
`I’-l5Dc2l
`l’450cll
`P-'l50aldo
`l’450arom
`11—HSD2
`
`l7<1-Hydroxylase/17,20-lyase
`3i}-Hydroxysteroid dehydroge-
`nase/A‘ -A‘-isomerase
`21-Hydroxylase
`l ll}-Hydroxylase
`Aldosterone synthase
`Aroniatase
`
`1ll}-Hydroxysteroid dehydrogenase
`
`TABLE 72-2.
`Characteristics of Enzymes Involved in Adrenal Steroid Biosynthesis
`Number
`Number
`Amino Acids‘
`Clirumosonic
`Gene Size (kb)
`Siibcellular Location
`Exons
`Enzyme
`Alias
`Gene
`
`CYPHA
`P-lS0scc
`Cholesterol desmolase
`CYP17
`I’450cl7
`HSDBBZ
`
`15q23-2-l
`1oq24.3
`1p 1 1-13
`
`9
`8
`4
`
`3
`
`Mitochondria
`ER
`ER
`
`3
`
`.9M[0[xi[0Ix.)N7‘co
`—-—-0c0:ChU1.2.2..Dt\)Ix)
`
`—-
`
`10
`9
`9
`9
`5
`
`494
`503/479
`503 /479
`503
`405
`
`BR
`Mitochondria
`l\/litochondria
`ER
`ER
`
`ER, endoplasmic reticulum.
`‘Mitochondrial enzymes are synthesized as proliormones that are cleaved in mitochondria to the mature proteins; both sizes are g1\'L’I1-
`
`
`importation rapidly
`hood now appears that mitochondrial
`inactivates StAR.7’ The mechanism by which StAR mediates
`cholesterol transport across the mitochondrial membrane is not
`yet known.
`StAR clearly is not the only protein that mediates cholesterol
`transfer across the mitochondrial membrane. Another protein
`that appears necessary (but not sufficient, at
`least
`in the
`adrenals and gonads) for this process is the periplicrnl bciizodi'nz-
`cpiiie receptor, an 18-kDa protein in the mitochondrial outer
`membrane that is complexed with the mitochondrial voltage-
`dependent anion carrier in contact sites between the outer and
`inner mitochondrial membranes?‘ This protein does not appear
`to be directly regulated by typical trophic stimuli but is stimu-
`lated by cizdozepiiics, peptide hormones also called dfflZL’}7llHI-
`liindiiig iiilzibitors. Ell[l()Zt’pfIlL’S may be regulated by ACTH to
`some extent, but not with a rapid time course. Thus far,
`whether or not a direct physical
`interaction exists between
`StAR and the peripheral benzodiazepine receptor is not clear.
`
`ENZYMES
`
`The enzymes required for adrenal steroid biosynthesis com-
`prise two classes: cytoc/ironic P450 L’llZ_l/HIUS and short cliniii dehy-
`drogcmiscs (Table 72-2).‘ These enzymes are located in either the
`lipophilic membranes of the smooth endoplasmic reticulum or
`the mitochondrial inner membrane. As the successive biosyn-
`thetic reactions involved in steroidogenesis occur, the adrenal
`steroids shuttle between the mitochondria and the smooth
`endoplasmic reticulum (Fig. 72-3).
`
`CYTOCH ROME P450 ENZYMES
`
`Cytochrome P450 (CYP) Ulllgl/HIPS are responsible for most of the
`enzymatic conversions from cholesterol to biologically active
`steroid l1ormoiies.7"° Five P450 enzymes are involved in cortisol
`and aldosterone synthesis (see Table 72-2). Three——CYI’1lA
`(cholesterol desmolase,
`I’-'l50scc;
`the ”scc” stands for ”side
`chain cleavage”), CYI’llBl
`(llll-hydroxylase,
`I’450cll), and
`CYl’1_lB2 (aldosterone synthase, I’/450aldo)—have been local-
`ized in mitochondria;
`two—~CYl’l7 (‘l7(r-l’iydroxylase/17,20-
`lyase,
`l’450c17) and CYP21 (21-hydroxylase,
`l’~’l50c2l)—are
`located in the endoplasmic reticulum (see Fig. 72-3).
`P430 ciizi/iiics are membrane-bound hemoproteins with
`molecular masses of ~50 l<Da. Their name arises from their
`property of absorbing light at a peak wavelength of 450 nm.
`These enzymes are located in the membranes of the smooth
`endoplasmic reticulum and the mitochondrial inner membrane
`and are encoded by a large superfamily of genes.7
`P4505 are ziiixcrifiriictitiii oxidnses. They use molecular oxygen
`and reducing equivalents (i.e., electrons) provided by reduced
`nicotinamide—adenine dinucleotide phosphate (NADPH) to eat-
`
`alyze oxidative conversions of an extremely Wide Variety Of
`mostly lipophilic substrates.
`)i d‘
`)
`1
`f
`The reducing equivalents are not accept“ V 1r‘CtY For?‘
`NADPH but instead from accessory electron transport prot51II)1Is{.
`These accessory proteins are necessaf)’ became NA_
`Y1
`donates electrons in pairs, whereas I’45_0S Can Only accept 5m3; 3
`electrons? Microsomal P4505 use a Slflgle ‘fife:/S9ryhPr°:1e1.ni
`NADPH-dependent cytochrome P450 reductase.
`litpc OI;
`r1_a
`P4505 require two proteins; NADPH'dePe‘?de“t “F re“? Oxm
`reductase donates electrons to adrenodoxin, which in turn
`transfers them to the P450." Adrenodoixlfl (Or ferred:).X]n[)\Criec}uC-
`tase, like cytochrome P450 reductase, 15 3 f_1<"1V0PI‘0tclp. dung-
`doxin (or ferredoxin) contains nonheme lF0n‘C0'mP exe
`‘fl 1
`sulfur. One gene encodes each acceSSQrY P_r°tem 1“ mamma
`t
`The heart of the P450 catalytic site 15 3 hemelgroup t a
`interacts with a highly conserved peptide of_the
`1.? cpg;
`pletely conserved cysteine near the C terminus
`15 l 9
`1
`
`Plasma Membrane
`
`Cholesterol
`
`CYP11A
`
`Pregnenolone
`
`Mitochondrion
`
`CYP11B1
`
`1 1_Deoxycortiso|
`
`17OH Pregnenolone
`
`CYP21
`
`17OH progesterone
`
`EndoplasmicReticulum
`
`3{3HSD
`A5—A4 lsomerase
`
`u._.____j___
`
`.J
`
`FIGURE 72-3. Biosynthesis of cortisol fl’
`names of the steroidogenic enzymes arc
`72-4.
`
`Om cholesterol. The functional
`listed in Table 72-2 and Figure
`
`

`

`Ch. 72: Synthesis and Metabolism of Corticosteroids
`
`707
`
`HO
`
`CHOLESTEROL
`
`ll
`
`0
`
`PREGNENOLONE
`
`PROGESTERONE
`
`1 1»DEOXY -
`CORTICOSTERONE
`
`0
`"OH
`
`33
`
`(Sal
`HO’C £
`
`17-HYDROXY-
`PREGNENOLONE
`
`CORTICOSTERONE
`OH
`
`O
`
`HO
`
`..OH
`
`18 -HYDROXY-
`CORTICOSTERONE
`
`ALDOSTERONE
`
`MINERALOCORTICOIDS
`
`Enzymatic Steps:
`
`1. CYP11A: 20. 22-Hydroxylase
`20, 22-Desmolase
`
`2. 3[3—Hydroxysteroid Dehydrogenase
`A5-A‘ isomerase
`
`3. CYP17: 17 a-Hydroxylase (3a)
`17, 20-Lyase (Sb)
`
`4. CYP21: 21-Hydroxylase
`
`5. CYP11B1: 11 ,8-Hydroxylase
`
`6, CYP11B2: 11 B—Hydroxylase (Ba)
`18-Hydroxyiase (6b)
`18-Oxidase (6c)
`
`7. 17—Ketosteroid Reductase
`
`8. CYP19: Aromatase
`
`9. 3 ii-Hydroxysteroid Sulfotransterase
`
`0
`
`‘l7-HYDROXY-
`PROGESTERONE
`
`11<DEOXY-
`CORTISOL
`
`CORTISOL
`
`GLUCOCORTICOIDS
`
`A‘-/KNDROSTENEDIONE
`
`ESTRONE
`
`so,
`
`DEHYDROEPL
`ANDROSTERONE
`SULFATE
`
`DEHYDROEPl-
`ANDROSTERONE
`
`OH
`
`HO
`
`OH
`
`.192
`iligjé
`
`0
`
`A5_ANDRoS-I-ENE,
`DIOL
`
`TESTOSTERONE
`
`ANDROGENS
`
`7?:
`
`0..
`
`HO
`
`ESTRADIOL
`
`ESTROGENS
`
`FIGURE 72-4 The steroidogenic pathway and e“ZYm““° Steps’
`
`.
`
`'
`
`lirand is either
`
`ligand of the heme iron aetr(1>mV.\nT:: ggygegxgslboiandl the long
`Water or molecular OXyg1 "
`"trallel with the axis of the heme
`axis of the oxygen molecp 1e is E:/eml proposed models of Cata1_
`iron. According to one o tie sion is binding of Substrate to OXi_
`ySiS'“ the first Stgp of lhe reaCOiie electron is donated from the
`dized (ferric Fe”) emymet
`rotein to the enzyme so that the
`accessory electron tmmfpor ups Fe“) State. This complex binds
`iron is in the reduced (firm accepts a second electron from the
`moleclllar Oxygfm and
`(inthe bound oxygen molecule with a
`accessor)’ Pmten" lem‘/11.“5:11 Oxygen atom accepts two Protons
`negative Charge‘ Tlhe
`residue, possibly via a bound water
`from a conservefiiilsltflogxygen atom is then released as a water
`molecule‘ ‘ The.
`1 the iron in the Fe“ state. The remaining
`molecule! lezwmg.
`1 1
`reqctive (the iron-oxygen complex is a
`Ogygeil awn.‘ 1t:,)111§r:dyatt(1cks
`the substrate, resulting in an
`” erry ” moie
`c
`‘
`hydroxylatlon’
`dase (cYP11A, P450scc). The first enzy-
`cholesterd Desm ‘d 1 ormone biosynthesis is the conversion
`matic step in all steroi
`i
`lone by CYPHA (Fig. 724; See also
`of cholesterollto pregnenohl 293 20% and 22R_hydr0xy1atiOn
`Fit} 72'3)- T1115. wtymel Ca C 33 of the C7042 carbon bond of cho-
`followed by Oxldatlve C eavagjde chain.15 These reactions require
`lesteufl ti?tieleascxtfi/1§eE2§(:l:CL1leS and six electrons. Like other
`a tow 0 We 0
`,
`7
`~ CYP11A receives
`mitochondrial Cytoc111~(R1§PITI43?r(::;Z’TgfglacceSsory proteins’
`these elections from qnd adrenodoxin. The three oxidations
`adrenodoxifi regzfftgrfiéd in succession without
`release of
`are norma y
`_
`.
`intermediates from the enzyme.
`hydCr$()[())i11a/txeii structurally related to the CYP1lB (11B—hydroxy—
`hse) isozymes (see later). It is synthesized as a precursor pro-
`tfein As is the case with other mitochondrial proteins encoded
`
`by nuclear genes, an amino-terminal peptide is required for
`transport to the mitochondrial inner membrane. This peptide
`of 39 residues is removed in the mitochondria to yield the
`mature protein.
`170:-Hydroxylase/17,20—Lyase (CYP17, P450c17).
`CYP17
`catalyzes conversion of pregnenolone to 17
`—hydroxyp1-eg_
`nenolone. In rats, this enzyme also converts progesterone to 17-
`hydroxyprogesterone, but progesterone is not a good substrate
`for the human enzyme. CYP'l7 also catalyzes an oxidative
`cleavage of
`the 17,20 carbon-carbon bond, converting 17_
`hydroxypregnenolone and 17-hydroxyprogesterone to dehydr0_
`epiandrosterone (DHEA) and androstenedione, respectively};
`A pair of electrons and a molecule of oxygen are required for
`each hydroxylation or lyase reaction. CYP17 is a microsomal
`cytochrome P450 and accepts these electrons from NAD[>H_
`dependent cytochrome P450 reductase.
`In the human adrenal cortex, 170i-hydroxylase activity is
`required for the synthesis of cortisol. The human enzyme pref;
`erentially uses pregnenolone rather than progesterone, 3 C1
`3B-hydroxysteroid dehydrogenase then converts 17-hydrOXy_
`pregnenolone to 17—hydroxyprogesterone. Because most I‘Ode11tS
`do not express CYP17 in the adrenal cortex, they secrete cor -
`costerone as their primary glucocorticoid. Both 170L-
`lase and 17,20—1yase activities are required for and
`estrogen biosynthesis.
`Because the same enzyme catalyzes production of cortisol -1
`the adrenal cortex and androgens in the gonads, the rglativll
`level of 17,20-lyase activity must be independently regulated be
`a mechanism other than gene expression, or else excessivz
`amounts of androgens would be synthesized in the adrena1 COP
`tex. Cytochrome b5 levels are likely to be one such mechanism
`because interactions with cytochrome b5 increase 17,20-1yase’
`
`

`

`-
`
`,
`
`2 r
`
`' >rved cofactor-binding domain near the N
`tyrosine and lysine residues near the C
`I
`,
`.-.20
`"1 n‘
`>1
`-
`‘
`‘
`‘
`.
`terminus that are crucial for cataly1sis.l
`l1"l1€Xl)’15(l)f;tthf’0V1"n
`ers the ‘1pparem.pK“ of the Plwno ll:
`lyclimsilolti ricy ran re The
`10.0’
`its Value In Sollmmlll mtbl ttoercpmllx e 1 lpjI'0l0l1 flforn the
`,
`.
`'5 tien a
`C
`’
`’
`<
`substrate, which facilitates transfer of a
`.
`>
`'
`" ’
`1
`t
`.
`.
`hydride from the substrate to the cgxpliztcd
`qdrelnl Cor-
`_
`The most important enzyme o tiis ‘)1?’ ‘I _‘
`‘
`)
`.‘_
`1
`tex is 3l5~l1ydroXY5ter°id dehydmgemse
`H5 emymt 15 on y
`45% identical
`to most other short chain dehydrogenases,
`1th
`yh ‘t retains the essential structural features of this class
`31? eggéjmés Octher enzymes of this type that are important in
`steroidy metabolism include 11B-hydroxysteroid dehydroge-
`1 - h imerconverts cortisol and cortisone, and l7-l<eto-
`1-Zslciuctqse which converts androstenedione and estrone
`‘V
`‘
`‘
`I
`V
`‘
`1, r85 eCtlVCly.*°
`
`—
`
`708
`
`PART V: THE ADRENAL GLANDS
`
`activity, and mutations in cytochrome b5 interfere with andro-
`gen biosynthesis. Phosphorylation of specific serines and thre-
`onines in CYP17 may also be important.”
`21-Hydroxylase (CYP21, P450021).
`The enzyme 21~hydroxy-
`lase resides in the endoplasmic reticulum and is responsible for
`hydroxylating 17-hydroxyprogesterone to ‘ll-deoxycortisol and
`progesterone to 11-deoxycorticosterone. The preferred substrate
`for the human enzyme is 17-hydroxyprogesterone. The structural
`gene encoding human CYPZI (CYP21, CYP21/l2, or CYPZIB) and
`a pseudogene (CYI’21I’, CYI’21A1I’, or CYI’21A) are located in the
`HLA major histocompatibility complex on chromosome 6p21.3
`~30 kilobases (kb) apart, adjacent to and alternating with the C48
`and CIA genes encoding the fourth component of serum comple-
`ment. Both the CYP2'I and C4 genes are transcribed in the same
`direction. CYP21 and CYI’21I’ each contain 10 exons spaced over
`3.1 kb. Their nucleotide sequences are 98% identical in exons and
`~96"/o identical in introns. This tandem duplication is genetically
`unstable and frequent recombinations occur between CYP21 and
`CYI’21I’, causing congenital adrenal hyperplasia due to 21-
`hydroxylase deficiencyl'3 (see Chap. 77).
`The two microsomal enzymes, CYP2l and CYP17, are 36%
`identical in amino-acid sequence and their genes have a similar
`intron-exon organization, a finding which suggests that both
`genes evolved from a common ancestor.”
`11B-Hydroxylase (CYP11B1, P450011) and Aldosterone
`Synthase (CYP11B2, P450a|do). Humans have distinct
`l1[3-
`hydroxylase isozymes, CYI’11B1 and CYI’11B2, that are responsi-
`ble for cortisol and aldosterone biosynthesis, respectively. In vitro,
`both isozymes can convert Ill}-hydroxylate l1-deoxycorticoster-
`one to corticosterone and ll-deoxycortisol to cortisol. CYI’llB2
`also has 18-hydroxylase and 18-oxidase activities, so that it can
`convert deoxycorticosterone to aldosterone.
`In contrast,
`the
`CYI’1'lB’l
`isozyme does not synthesize detectable amounts of
`aldosterone from corticosterone or 18-hydroxycorticosterone.18
`These isozymes are mitochondrial cytochrome P450 enzymes
`and are synthesized with a signal peptide that is cleaved in mito-
`chondria. The sequences of
`the proteins are 93% identical.
`CYI’11B1 and CYP‘l1B2 are encoded by two genes on chromo-
`some 8q2'l-q22. CYI’11B2 is located to the left of CYI’l1B1 if the
`genes are pictured as being transcribed from left to right; the genes
`are located approximately 40 kb apart. The location of introns in
`each gene is identical to that seen in the CYI’11A gene encoding
`cholesterol desmolase, and the predicted protein sequences of the
`CYP'llB isozymes are each ~36% identical to that of CYI’l‘lA.
`CYI’llBl
`is expressed at high levels in normal adrenal
`glands. CYI"l1B2 is normally expressed at low levels, but its
`expression is dramatically increased in aldosterone-secreting
`tumors. Transcription of CYI"l1Bl
`is regulated mainly by
`ACTH, whereas CYI’1lB2 is regulated by angiotensin II and
`potassium levels (see later). Recombinations between these two
`genes can lead to abnormal regulation of CYI’llB2 and cause
`hypertension,
`a condition termed glzlcvcorticoid suppressiblc
`/Iypernlriostrroizisiiz (see Chap. 80).
`
`SHORT CHAIN DEHYDROGENASES
`Most short chain dehydrogenases catalyze reversible reactions.”
`In the dehydrogenase direction, a hydride (i.e., a proton plus
`two electrons) is removed from the substrate and transferred to
`an electron acceptor that, depending on the enzyme, is oxidized
`nicotinamide-adenine dinucleotide (NAD+) or oxidized nico-
`tinamide-adenine dinucleotide phosphate (NADI’+).
`If,
`for
`example,
`the reaction involves a hydroxylated substrate,
`the
`reaction converts the hydroxyl
`to a keto group; NADH or
`.
`and a proton are also produced. Oxoreductase reac-
`tions reverse this process. Unlike oxidations mediated by cyto-
`chrome P450 enzymes, no accessory protein is required for these
`reactions.
`
`Most short chain dehydrogenases contain 250 to 300 amino-
`acid residues. Some enzymes are found in cytosol, whereas oth-
`ers are located mainly in the endoplasmic reticulum. These
`
`.
`
`Version of A5-3fi-hydroxysteroids (pregnenolone, l7-hydroxy-
`re menolone DHEA)
`to A4-3-ketosteroids (progesterone,
`l)7'll‘)YdrOXYF’rog€Sterone
`androstenedione) is mediatied py 3B-
`I
`. ,
`-
`N
`l
`‘
`c
`‘
`I
`$313.2 ;i..t;:.::::.:*;::::?‘;.:
`r9t1CU1Um- Thls enzyme uses .
`l 1‘ dro ’en'1se activit
`the
`addition to 3[3-hydroxysteroid ce 1y
`39
`.
`‘ H t
`‘
`,
`,
`,
`dimes a A5_A»1_ene15OI1’l(,‘1'£lSe reaction ia trans ers a
`:iI(1)f1}1/3I1T1(.bT§re1d from the B ring to the A ring of the steroid so that
`Q
`.
`.
`,
`,
`_
`.
`,
`y
`,
`=
`t2
`‘
`'
`‘
`c
`it is conjugated with the 3-keto §,f0UP Cg nn léoéynlesjre
`«,1 0
`b1
`t) rnedi']t(_ 3 ketosteroid reduction of several sub-
`‘ s
`a
`e
`(
`c
`‘
`'
`-
`_
`strates using NADH as an electron don(>r.lG:i1<(>iH1P1I£Sll3l3<>IE 3“?‘lY'
`’
`x
`V_
`‘
`‘
`-
`) 0. ,n , .
`sis suggests that as many as .'>1X‘ closely) ripe ) 1 t 1” ,gf)—“;-1:
`exist in humans but only two 1S0Z)’”I“.5 “WC ‘C U‘
`l
`,
`, .)
`’
`)
`, t1 ,
`t
`e
`isozyme expressec in
`1dent1f1Ld' T813331 Ulcoclwf
`gllpwhereas HSDSBZ encodes
`Placenta, sl<in, and adipose iiss th,e qdmmls and gumdstzz The
`the WP9 H ‘50ZYm9 expr