The developmental changes in plasma adrenal androgens during infancy and adrenarche are associated with changing activities of adrenal microsomal 17-hydroxylase and 17,20-desmolase

The Search for the Causes of Common Hyperandrogenism, 1965 to Circa 2015

From 1965 to 2015, immense strides were made into understanding the mechanisms underlying the common androgen excess disorders, premature adrenarche and polycystic ovary syndrome (PCOS). The author reviews the critical discoveries of this era from his perspective investigating these disorders, commencing with his early discoveries of the unique pattern of plasma androgens in premature adrenarche and the elevation of an index of the plasma free testosterone concentration in most hirsute women. The molecular genetic basis, though not the developmental biologic basis, for adrenarche is now known and 11-oxytestosterones shown to be major bioactive adrenal androgens. The evolution of the lines of research into the pathogenesis of PCOS is historically traced: research milestones are cited in the areas of neuroendocrinology, insulin resistance, hyperinsulinism, type 2 diabetes mellitus, folliculogenesis, androgen secretion, obesity, phenotyping, prenatal androgenization, epigenetics, and complex genetics. Large-scale genome-wide association studies led to the 2014 discovery of an unsuspected steroidogenic regulator DENND1A (differentially expressed in normal and neoplastic development). The splice variant DENND1A.V2 is constitutively overexpressed in PCOS theca cells in long-term culture and accounts for their PCOS-like phenotype. The genetics are complex, however: DENND1A intronic variant copy number is related to phenotype severity, and recent data indicate that rare variants in a DENND1A regulatory network and other genes are related to PCOS. Obesity exacerbates PCOS manifestations via insulin resistance and proinflammatory cytokine excess; excess adipose tissue also forms testosterone. Polycystic ovaries in 40 percent of apparently normal women lie on the PCOS functional spectrum. Much remains to be learned.

Formation, structure, and function of extra-skeletal bones in mammals

This review describes the formation, structure, and function of bony compartments in antlers, horns, ossicones, osteoderm and the os penis/os clitoris (collectively referred to herein as AHOOO structures) in extant mammals. AHOOOs are extra-skeletal bones that originate from subcutaneous (dermal) tissues in a wide variety of mammals, and this review elaborates on the co-development of the bone and skin in these structures. During foetal stages, primordial cells for the bony compartments arise in subcutaneous tissues. The epithelial-mesenchymal transition is assumed to play a key role in the differentiation of bone, cartilage, skin and other tissues in AHOOO structures. AHOOO ossification takes place after skeletal bone formation, and may depend on sexual maturity. Skin keratinization occurs in tandem with ossification and may be under the control of androgens. Both endochondral and intramembranous ossification participate in bony compartment formation. There is variation in gradients of density in different AHOOO structures. These gradients, which vary according to function and species, primarily reduce mechanical stress. Anchorage of AHOOOs to their surrounding tissues fortifies these structures and is accomplished by bone-bone fusion and Sharpey fibres. The presence of the integument is essential for the protection and function of the bony compartments. Three major functions can be attributed to AHOOOs: mechanical, visual, and thermoregulatory. This review provides the first extensive comparative description of the skeletal and integumentary systems of AHOOOs in a variety of mammals.

Effect of n-3 and n-6 Polyunsaturated Fatty Acids on Microsomal P450 Steroidogenic Enzyme Activities and In Vitro Cortisol Production in Adrenal Tissue From Yorkshire Boars

Dysregulation of adrenal glucocorticoid production is increasingly recognized to play a supportive role in the metabolic syndrome although the mechanism is ill defined. The adrenal cytochrome P450 (CYP) enzymes, CYP17 and CYP21, are essential for glucocorticoid synthesis. The omega-3 and omega-6 polyunsaturated fatty acids (PUFA) may ameliorate metabolic syndrome, but it is unknown whether they have direct actions on adrenal CYP steroidogenic enzymes. The aim of this study was to determine whether PUFA modify adrenal glucocorticoid synthesis using isolated porcine microsomes. The enzyme activities of CYP17, CYP21, 11β-hydroxysteroid dehydrogenase type 1, hexose-6-phosphate dehydrogenase (H6PDH), and CYP2E1 were measured in intact microsomes treated with fatty acids of disparate saturated bonds. Cortisol production was measured in a cell-free in vitro model. Microsomal lipid composition after arachidonic acid (AA) exposure was determined by sequential window acquisition of all theoretical spectra-mass spectrometry. Results showed that adrenal microsomal CYP21 activity was decreased by docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), eicosapentaenoic acid, α-linolenic acid, AA, and linoleic acid, and CYP17 activity was inhibited by DPA, DHA, eicosapentaenoic acid, and AA. Inhibition was associated with the number of the PUFA double bonds. Similarly, cortisol production in vitro was decreased by DPA, DHA, and AA. Endoplasmic enzymes with intraluminal activity were unaffected by PUFA. In microsomes exposed to AA, the level of AA or oxidative metabolites of AA in the membrane was not altered. In conclusion, these observations suggest that omega-3 and omega-6 PUFA, especially those with 2 or more double bonds (DPA, DHA, and AA), impede adrenal glucocorticoid production.

Premature adrenarche: etiology, clinical findings, and consequences

Adrenarche means the morphological and functional change of the adrenal cortex leading to increasing production of adrenal androgen precursors (AAPs) in mid childhood, typically at around 5-8 years of age in humans. The AAPs dehydroepiandrosterone (DHEA) and its sulfate conjugate (DHEAS) are the best serum markers of adrenal androgen (AA) secretion and adrenarche. Normal ACTH secretion and action are needed for adrenarche, but additional inherent and exogenous factors regulate AA secretion. Inter-individual variation in the timing of adrenarche and serum concentrations of DHEA(S) in adolescence and adulthood are remarkable. Premature adrenarche (PA) is defined as the appearance of clinical signs of androgen action (pubic/axillary hair, adult type body odor, oily skin or hair, comedones, acne, accelerated statural growth) before the age of 8 years in girls or 9 years in boys associated with AAP concentrations high for the prepubertal chronological age. To accept the diagnosis of PA, central puberty, adrenocortical and gonadal sex hormone secreting tumors, congenital adrenal hyperplasia, and exogenous source of androgens need to be excluded. The individually variable peripheral conversion of circulating AAPs to biologically more active androgens (testosterone, dihydrotestosterone) and the androgen receptor activity in the target tissues are as important as the circulating AAP concentrations as determinants of androgen action. PA has gained much attention during the last decades, as it has been associated with small birth size, the metabolic and polycystic ovarian syndrome (PCOS), and thus with an increased risk for type 2 diabetes and cardiovascular diseases in later life. The aim of this review is to describe the known hormonal changes and their possible regulators in on-time and premature adrenarche, and the clinical features and possible later health problems associating with PA.

SET/PP2A system regulates androgen production in ovarian follicles in vitro

SET has multiple cell functions including nucleosome assembly, histone binding, transcription control, and cell apoptosis. In ovaries SET is predominantly expressed in theca cells and oocytes. In our study, SET overexpression in theca cells stimulated testosterone production whereas SET knockdown decreased testosterone production. Moreover, SET negatively regulated PP2A activity. Treatment with PP2A inhibitor okadaic acid (OA) led to increased testosterone synthesis, while treatment with PP2A activators resulted in the decreased testosterone synthesis. Furthermore, PP2A knockdown confirmed the key role of PP2A in the testosterone synthesis, and OA was able to block the AdH1-SiRNA/SET-mediated inhibition of testosterone production. The central role of PP2A in SET-mediated regulation of testosterone production was confirmed by the finding that SET promoted the lyase activity of P450c17 and that PP2A inhibited its lyase activity. Taken together, these results reveal a specific, SET-initiated, PP2A-mediated, pathway that leads to the increased lyase activity of P450c17 and testosterone biosynthesis.

Adrenarche in nonhuman primates: the evidence for it and the need to redefine it

Adrenarche is most commonly defined as a prepubertal increase in circulating adrenal androgens, dehydroepiandrosterone (DHEA) and its sulfo-conjugate (DHEAS). This event is thought to have evolved in humans and some great apes but not in Old World monkeys, perhaps to promote brain development. Whether adrenarche represents a shared, derived developmental event in humans and our closest relatives, adrenal androgen secretion (and its regulation) is of considerable clinical interest. Specifically, adrenal androgens play a significant role in the pathophysiology of polycystic ovarian disease and breast and prostate cancers. Understanding the development of androgen secretion by the human adrenal cortex and identifying a suitable model for its study are therefore of central importance for clinical and evolutionary concerns. This review will examine the evidence for adrenarche in nonhuman primates (NHP) and suggest that a broader definition of this developmental event is needed, including morphological, biochemical, and endocrine criteria. Using such a definition, evidence from recent studies suggests that adrenarche evolved in Old World primates but spans a relatively brief period early in development compared with humans and some great apes. This emphasizes the need for frequent longitudinal sampling in evaluating developmental changes in adrenal androgen secretion as well as the tenuous nature of existing evidence of adrenarche in some species among the great apes. Central to an understanding of the regulation of adrenal androgen production in humans is the recognition of the complex nature of adrenarche and the need for more carefully conducted comparative studies and a broader definition in order to promote investigation among NHP in particular.

Orteronel (TAK-700), a novel non-steroidal 17,20-lyase inhibitor: effects on steroid synthesis in human and monkey adrenal cells and serum steroid levels in cynomolgus monkeys

Surgical or pharmacologic methods to control gonadal androgen biosynthesis are effective approaches in the treatment of a variety of non-neoplastic and neoplastic diseases. For example, androgen ablation and its consequent reduction in circulating levels of testosterone is an effective therapy for advanced prostate cancers. Unfortunately, the therapeutic effectiveness of this approach is often temporary because of disease progression to the 'castration resistant' (CRPC) state, a situation for which there are limited treatment options. One mechanism thought to be responsible for the development of CRPC is extra-gonadal androgen synthesis and the resulting impact of these residual extra-gonadal androgens on prostate tumor cell proliferation. An important enzyme responsible for the synthesis of extra-gonadal androgens is CYP17A1 which possesses both 17,20-lyase and 17-hydroxylase catalytic activities with the 17,20-lyase activity being key in the androgen biosynthetic process. Orteronel (TAK-700), a novel, selective, and potent inhibitor of 17,20-lyase is under development as a drug to inhibit androgen synthesis. In this study, we quantified the inhibitory activity and specificity of orteronel for testicular and adrenal androgen production by evaluating its effects on CYP17A1 enzymatic activity, steroid production in monkey adrenal cells and human adrenal tumor cells, and serum levels of dehydroepiandrosterone (DHEA), cortisol, and testosterone after oral dosing in castrated and intact male cynomolgus monkeys. We report that orteronel potently suppresses androgen production in monkey adrenal cells but only weakly suppresses corticosterone and aldosterone production; the IC(50) value of orteronel for cortisol was ~3-fold higher than that for DHEA. After single oral dosing, serum levels of DHEA, cortisol, and testosterone were rapidly suppressed in intact cynomolgus monkeys. In castrated monkeys treated twice daily with orteronel, suppression of DHEA and testosterone persisted throughout the treatment period. In both in vivo models and in agreement with our in vitro data, suppression of serum cortisol levels following oral dosing was less than that seen for DHEA. In terms of human CYP17A1 and human adrenal tumor cells, orteronel inhibited 17,20-lyase activity 5.4 times more potently than 17-hydroxylase activity in cell-free enzyme assays and DHEA production 27 times more potently than cortisol production in human adrenal tumor cells, suggesting greater specificity of inhibition between 17,20-lyase and 17-hydroxylase activities in humans vs monkeys. In summary, orteronel potently inhibited the 17,20-lyase activity of monkey and human CYP17A1 and reduced serum androgen levels in vivo in monkeys. These findings suggest that orteronel may be an effective therapeutic option for diseases where androgen suppression is critical, such as androgen sensitive and CRPC.

Premature adrenarche: novel lessons from early onset androgen excess

Adrenarche reflects the maturation of the adrenal zona reticularis resulting in increased secretion of the adrenal androgen precursor DHEA and its sulphate ester DHEAS. Premature adrenarche (PA) is defined by increased levels of DHEA and DHEAS before the age of 8 years in girls and 9 years in boys and the concurrent presence of signs of androgen action including adult-type body odour, oily skin and hair and pubic hair growth. PA is distinct from precocious puberty, which manifests with the development of secondary sexual characteristics including testicular growth and breast development. Idiopathic PA (IPA) has long been considered an extreme of normal variation, but emerging evidence links IPA to an increased risk of developing the metabolic syndrome (MS) and thus ultimately cardiovascular morbidity. Areas of controversy include the question whether IPA in girls is associated with a higher rate of progression to the polycystic ovary syndrome (PCOS) and whether low birth weight increases the risk of developing IPA. The recent discoveries of two novel monogenic causes of early onset androgen excess, apparent cortisone reductase deficiency and apparent DHEA sulphotransferase deficiency, support the notion that PA may represent a forerunner condition for PCOS. Future research including carefully designed longitudinal studies is required to address the apparent link between early onset androgen excess and the development of insulin resistance and the MS.

Human cytochrome p450c17: single step purification and phosphorylation of serine 258 by protein kinase a

Cytochrome P450c17 (P450c17) is the single microsomal enzyme that catalyzes steroid 17alpha-hydroxylase and 17,20 lyase activities. The ratio of lyase to hydroxylase activity of human P450c17 determines whether steroidogenesis leads to the synthesis of cortisol or sex steroids. This ratio is regulated posttranslationally by factors that influence the efficiency of electron transfer from P450 oxidoreductase to P450c17. One factor favoring more efficient electron transfer and 17,20 lyase activity is cAMP-dependent serine/threonine phosphorylation of P450c17. Identifying the responsible kinase(s) and the P450c17 residues that undergo phosphorylation has been challenging, partly because of difficulties in preparing biochemically useful amounts of pure, catalytically active P450c17. We describe a modified strategy for preparing P450c17 in which the traditional carboxy-terminal 4xHis tag is replaced by 3xGly6xHis. This construct permits more rotational freedom of the protein when bound to the nickel affinity column, reducing steric associations between the protein and the column, and permitting a single-step chromatographic purification to apparent homogeneity. Using this vector, we explored P450c17 phosphorylation by mutagenesis of Ser and/or Thr residues to Asp or Glu to mimic the approximate size and charge of phospho-Ser or phospho-Thr. This strategy did not identify Ser and/or Thr site(s) that increase the ratio of lyase to hydroxylase activity, suggesting that the regulatory phosphorylation strategy of human P450c17 is very complicated. Although previous work has excluded protein kinase A (PKA) as the responsible kinase, the cAMP-inducible nature of the phosphorylation-associated increase in lyase activity suggests that PKA may play a role, possibly as a priming kinase. Using our novel vector and a series of mutations, we identified the P450c17 site phosphorylated by PKA as Ser258.

The developmental increase in adrenocortical 17,20-lyase activity (biochemical adrenarche) is driven primarily by increasing cytochrome b5 in neonatal rhesus macaques

Adrenarche is thought to be experienced only by humans and some Old World primates despite observed regression of an adrenal fetal zone and establishment of a functional zona reticularis (ZR) in other species like rhesus macaques. Adrenal differentiation remains poorly defined biochemically in nonhuman primates. The present studies defined ZR development in the neonatal rhesus by examining androgen synthetic capacity and factors affecting it in rhesus and marmoset adrenals. Western immunoblots examined expression of 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17), cytochrome b5 (b5), and 3beta-hydroxysteroid dehydrogenase (3betaHSD), among other key enzymes. 17,20-lyase activity was quantified in adrenal microsomes, as was the contribution of b5 to 17,20-lyase activity in microsomes and cell transfection experiments with rhesus and marmoset P450c17. Expression of b5 increased from birth to 3 months, and was positively correlated with age and 17,20-lyase activity in the rhesus. Recombinant b5 addition stimulated 17,20-lyase activity to an extent inversely proportional to endogenous levels in adrenal microsomes. Although 3betaHSD expression also increased with age, P450c17, 21-hydroxylase cytochrome P450, and the redox partner, reduced nicotinamide adenine dinucleotide phosphate-cytochrome P450 oxidoreductase, did not; nor did recombinant cytochrome P450 oxidoreductase augment 17,20-lyase activity. Cotransfection with b5 induced a dose-dependent increase in dehydroepiandrosterone synthesis by both nonhuman primate P450c17 enzymes. We conclude that the increase in 17,20-lyase activity characteristic of an adrenarche in rhesus macaques is driven primarily by increased b5 expression, without the need for a decrease in 3betaHSD, as suggested from human studies. The rhesus macaque is a relevant and accessible model for human ZR development and adrenal function.

Continuum of phenotypes and sympathoadrenal function in premature adrenarche

OBJECTIVES

Premature adrenarche (PA), the early rise in adrenal androgen (AA) production, can manifest with different clinical signs of androgen effect. Premature pubarche defined as appearance of pubic hair before the age of 8/9 years in girls/boys, is the most prominent clinical sign of PA and often erroneously described as a synonym of PA. Our aim was to determine the association of circulating AA concentrations with different prepubertal signs of androgen action (SAA). Secondly, we tested whether adrenomedullary function is altered in children with SAA, as it is in congenital adrenal hyperplasia (CAH) also causing adrenal hyperandrogenism.

DESIGN AND METHODS

We examined 73 Finnish prepubertal children with any hyperandrogenic sign(s) having appeared before the age of 8/9 years (girls/boys) (35 with pubic and/or axillary hair=PAH; 38 without=nonPAH), and 98 age- and sex-matched controls. Circulating adrenal steroid and catecholamine concentrations were measured and correlated with clinical parameters.

RESULTS

None of the children with SAA had CAH or virilizing tumor. Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione concentrations overlapped between the SAA and control children, and they were lower in the nonPAH than PAH group (P<0.01). SAA children had similar plasma epinephrine but higher norepinephrine (NE) concentrations than their controls (mean (95% confidence interval) 1.61 (1.44, 1.77) versus 1.39 (1.30, 1.49) nmol/l, P=0.03).

CONCLUSIONS

PA forms a continuum with more pronounced increase in circulating androgens in children with PAH than in those without. Some children show SAA with fairly low androgen concentrations. The clinical significance of elevated NE concentrations associated with SAA needs to be confirmed in further studies.

Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome is a heterogeneous clinical syndrome, which has been defined as the association of hyperandrogenism with chronic anovulation in women without specific adrenal and pituitary gland disease. A family history of polycystic ovary syndrome may be present in a subset of patients; however, the genetic basis of the syndrome remains unclear. Most often, the age of onset is perimenarchal and it is characterized by the appearance of menstrual disturbances, hirsutism, acne, and more rarely, a male pattern of alopecia. In some cases, premature adrenarche may present as a precursor to the development of the syndrome. Polycystic ovary syndrome is also associated with metabolic disturbances, such as obesity and insulin resistance with hyperinsulinemia, for which the pathophysiological role in the development of the syndrome has been recognized. The therapeutic approaches to polycystic ovary syndrome include lifestyle modifications, dietary-induced weight loss, insulin-sensitizing agents, antiandrogens, and oral contraceptives. These treatments may improve the clinical manifestations of excess androgen production and normalize menses in many adolescents and young women with polycystic ovary syndrome. Early recognition of the syndrome and thus, early treatment, may prevent and possibly ameliorate all the symptoms and the potential later development of metabolic and cardiovascular complications.

Premature pubarche in girls is associated with functional adrenal but not ovarian hyperandrogenism

OBJECTIVE

We hypothesized that there would be evidence of functional ovarian hyperandrogenism in girls with premature pubarche (PP) at diagnosis.

METHODS

White girls <8 years of age and black girls <6 years with PP (n = 15) were studied. Prepubertal girls (n = 13; 5.3-10.9 years) and early pubertal girls (n = 8) served as control subjects. The biochemical marker for functional ovarian hyperandrogenism was the 17-hydroxyprogesterone (17-OHP), androstenedione (AD), and estradiol (E2) response to subcutaneous leuprolide during adrenal suppression with dexamethasone. This was studied in girls with PP and in control subjects.

RESULTS

ACTH stimulated 17-hydroxypregnenolone (17-OH Preg), dehydroepiandrosterone (DHEA), and AD levels, and 17-OH Preg:17-OHP and DHEA:AD ratios were significantly higher in girls with PP than in prepubertal control subjects (n = 18) (P < or =.003). The ovarian response to leuprolide stimulation was comparable in girls with PP and prepubertal control subjects, but the response in prepubertal study subjects was significantly lower than in pubertal control subjects (P =.016 for Delta17-OHP, P =.001 for DeltaAD, and P =.026 for DeltaE2).

CONCLUSIONS

Contrary to the hypothesis, PP in girls was not associated with prepubertal evidence of ovarian hyperandrogenism but was associated with functional adrenal hyperandrogenism.

Premature adrenarche

Adrenarche is the puberty of the adrenal gland. The descriptive term "pubarche" indicates the appearance of pubic hair, which may be accompanied by axillary hair. This process is considered premature if it occurs before age 8 yr in girls and 9 yr in boys. The chief hormonal products of adrenarche are DHEA and DHEAS. The well-documented evolution of adrenarche in primates and men is incompatible with either a neutral or harmful role for DHEA and implies most likely a positive role for some aspects of young adult pubertal maturation and developmental maturation. Premature adrenarche has no adverse effects on the onset and progression of gonadarche and/or final height. Mechanisms for initiation of adrenal androgen secretion at adrenarche are still not well understood. Maturational increases in 17-hydroxylase and 17,20-lyase are seen together with a lower activity of 3beta-hydroxysteroid dehydrogenase (3beta-HSD). There is good evidence that the zona reticularis is the source of adrenal androgens. Adrenarche and gonadarche are regulated differently. Although premature adrenarche has been thought to be a benign, normal variant of puberty, our findings indicate that, for certain girls, premature adrenarche represents an early clinical feature of syndrome X (obesity, hypertension, dyslipidemia, insulin resistance). Perhaps the early identification of these patients will permit early therapy, such as lifestyle changes, including dietary and activity level intervention. As insulin resistance is an underlying feature of premature adrenarche, it seems rational to assess the efficacy and safety of using insulin-sensitizing agents to treat these individuals. In the absence of controlled longitudinal studies, the cross-sectional data available from our studies suggest that premature pubarche driven by premature adrenarche and hyperinsulinemia may precede the development of ovarian hyperandrogenism, and this sequence may have an early origin with low birth weight serving as a marker. Premature adrenarche may thus be a forerunner of syndrome X in some girls.

The role of the adrenal cortex in polycystic ovary syndrome

Adrenal androgen excess affects approximately 25% of PCOS patients. The exact etiology of this excess in PCOS patients is unclear. Some evidence that adrenal androgen excess may be a genetic trait. The adrenal androgen response to ACTH is highly individualized, and the relative response seems to be constant over time. In addition, there is a strong familial component to adrenal androgen levels in normal individuals and PCOS patients. It is possible that the tendency to overproduce adrenal androgens is an inherited risk factor for the development of PCOS. Overall, few hyperandrogenic patients actually have isolated deficiencies of 3 beta-hydroxysteroid dehydrogenase, 21-hydroxylase, and 11-hydroxylase. The ovarian hormonal secretion in PCOS can affect adrenal androgen secretion and metabolism, although this factor accounts for only part of this abnormality. More likely, the adrenal androgen excess results from a generalized hyperresponsiveness of the adrenal cortex to ACTH, but without an increase in CRH or ACTH sensitivity. Although glucocorticoid administration may improve the ovulatory function of these patients, the results are modest and cannot be predicted by the circulating androgen levels.

Evidence of different actions of testosterone, estradiol, FSH, and LH on the growth axis

To study the possible role of sexual hormones, Testosterone (T), Estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) on the growth axis, we examined the correlations between the sex, growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP3), FSH, LH, T and E2, in growth retarded children ranging in age from 7 to 13 yr. All hormones were measured by Radioimmunoassay (RIA) in a pool of aliquots of samples obtained every 20 min over 12 h (overnight) in each child. Multivariate statistical analysis was performed. We have found: a) Thai only FSH concentrations were significantly higher in girls than in boys; b) A positive correlation between T-IGF-1; T-IGFBP3; FSH-LH; FSH-IGF-1; FSH-IGFBP3, LH-IGF-1, LH-IGFBP3 the sex-FSH; and the sex-IGFBP3 c) A high positive correlation between plasmatic E2 and IGF-1/IGFBP3 ratio (an index of free, active IGF-1). We concluded that the sex, FSH, LH, T and E2 influence the growth axis. The sex through IGFBP3; LH, FSH, and T through IGF1 and IGFBP3; E2 through the IGF-1/IGFBP3 ratio, an index of active IGF-1.

Intra-adrenal regulation of androgen synthesis

The adrenal cortex encloses the neuroendocrine medulla and is itself subdivided into three distinct zones, each having a specific function and regulation. While the glomerulosa and the fasciculata control vital systems of mineral and energy supply, which are stringently regulated by higher control factors, the function of the reticularis is less clear, beyond supplying a pool of weak androgens, and consequently we do not understand its redundant regulation. The following questions need to be answered: 1. How is the formation of dehydroepiandrosterone (DHEA) and androstenedione differently regulated from glucocorticoid synthesis in normally functioning adrenals? 2. How might growth factors, which increase prepubertally, prime the adrenarche? 3. The regulation of the 17/20-lyase enzyme activity is one of the key factors of adrenal androgen secretion (review [2]). How can the two activities of the P450c17 enzyme be differently regulated in the same cell in a developmentally dependent fashion? This review focuses on the intra-adrenal growth factor system and on the role of 17/20-lyase regulation, as well as on their possible interactions. The increase of activity of the 17/20-lyase enzymatic activity is necessary for the rise of C19 steroids, while the relative increase of formation of DHEA is only possible in the presence of a low 3beta-hydroxysteroid-dehydrogenase (3betaHSD) activity.

Developmental changes in steroidogenic enzymes in human postnatal adrenal cortex: immunohistochemical studies

Adrenarche is considered to occur as a result of intra-adrenal changes in steroidogenic enzymes involved in C19 steroid production. The present study was conducted because developmental changes in steroidogenic enzymes have not been examined well in human postnatal adrenal. Twenty-four specimens of nonpathological human adrenals from 7 months to 62 years retrieved from autopsy files. Immunohistochemistry for P450 side-chain cleavage (P450scc), 17alpha hydroxylase (P450c17), dehydroepiandrosterone sulfotransferase (DHEA-ST), P450 oxidoreductase, cytochrome b5, and 3beta-hydroxysteroid dehydrogenase (3betaHSD) was per-formed in these specimens, and the immuno-intensity was evaluated using CAS 200 computed image analysis system. Immunoreactivity of P450scc was marked in the zona glomerulosa, fasciculata and reticularis in the adrenal glands of all the cases examined. P450c17 and DHEA-ST immunoreactivity was weak in the zona fasciculata and reticularis in the adrenals of age 7 months to 5 years, but thereafter became prominent in the zona reticularis. Immunoreactivity of P450 oxidoreductase and cytochrome b5, components of the electron transfer system hypothesized to regulate the 17-20 lyase activity of P450c17, was weak in all three zones of adrenal cortex from 7 months to 5 years, and became more marked in the zona reticularis after age 5 years. 3betaHSD immunoreactivity was marked in all three zones of the adrenal cortex from 7 months to 8 years but thereafter decreased in the zona reticularis. These data suggest that the human adrenal zona reticularis markedly begins to develop morphologically and functionally at around 5 years of age. The increased level of P450c17, DHEA-ST, P450 oxidoreductase, and cytochrome b5, and the decreased level of 3betaHSD in the reticularis is likely to contribute to increased C19 steroid production during adrenarche.

Premature adrenarche--normal variant or forerunner of adult disease?

Adrenarche is the puberty of the adrenal gland. The descriptive term pubarche indicates the appearance of pubic hair, which may be accompanied by axillary hair. This process is considered premature if it occurs before age 8 yr in girls and 9 yr in boys. The chief hormonal product of adrenarche is dehydroepiandrosterone (DHEA) and its sulfated product DHEA-S. The well documented evolution of adrenarche in primates and man is incompatible with either a neutral or harmful role for DHEA and implies most likely a positive role for some aspect of young adult pubertal maturation and developmental maturation. Premature adrenarche has no adverse effects on the onset and progression of gonadarche in final height. Both extra- and intraadrenal factors regulate adrenal androgen secretion. Recent studies have shown that premature adrenarche in childhood may have consequences such as functional ovarian hyperandrogenism, polycystic ovarian syndrome, and insulin resistance in later life, sometimes already recognizable in childhood or adolescence. Premature adrenarche may thus be a forerunner of syndrome X in some children. The association of these endocrine-metabolic abnormalities with reduced fetal growth and their genetic basis remain to be elucidated.

The molecular basis of premature adrenarche: an hypothesis

Adrenarche is characterized by a prepubertal rise in adrenal secretion of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) that is independent of the gonads or gonadotropins. Adrenopause is the corresponding diminution in DHEA and DHEAS concentrations in later life. The mechanisms by which adrenarche and adrenopause are induced and regulated are unknown. Early work focused on identifying hypothetical adrenal androgen regulatory hormones that would induce DHEA in much the same way that adrenocorticotropin induces cortisol, but no such factors have been found. Current studies of adrenarche focus on intra-adrenal events, particularly those concerning 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 17alpha-hydroxylase/17,20-lyase (P450c17). Molecular data implicate a decrease in 3beta-HSD specifically in the adrenal zona reticularis. However, a decrease in 3beta-HSD is insufficient to explain why the reticularis catalyzes 17,20-lyase activity and hence makes DHEA, rather than catalyzing only 17alpha-hydroxylase activity, as does the zona fasciculata. P450c17 appears to catalyze 17,20-lyase activity only if P450c17 has undergone serine phosphorylation and has access to cytochrome b5 as an allosteric cofactor. Although these two factors have not yet been investigated in adrenarche, it appears that both a zone-specific diminution in 3beta-HSD and a zone-specific induction of 17,20-lyase activity are required to account for the physiological data. Exaggerated premature adrenarche appears to be an early sign of polycystic ovary syndrome (PCOS). Mechanistic considerations of PCOS suggest a key role for serine phosphorylation of P450c17 in both adrenarche and some forms of heritable PCOS.

Ovarian and adrenal function in polycystic ovary syndrome

Androgens are secreted by both the ovaries and adrenal glands in response to their respective trophic hormones LH and ACTH. Androgens in women are not specifically under negative feedback control by these pituitary hormones because they are by-products of estradiol and cortisol secretion. Rather, androgen secretion seems to be regulated mostly by intraglandular mechanisms. Functional ovarian hyperandrogenism is found in about 70% of patients with PCOS. It is characterized by excessive secretion of 17-hydroxyprogesterone in response to GnRH agonist or hCG stimulation. Failure of dexamethasone to suppress plasma free testosterone normally in the presence of normal adrenocortical suppression is also typical. Functional adrenal hyperandrogenism is found in about half of patients with PCOS. It is most often characterized by moderately increased secretion of the 17-ketosteroid DHEA in response to ACTH. The most likely cause of the excessive androgen secretion by both glands seems to be abnormal regulation (dysregulation) of the 17-hydroxylase and 17,20-lyase activities of P-450c17, the rate-limiting step in androgen biosynthesis. There are also subtle generalized disturbances of steroid metabolism, including tendencies toward excessive estrogen and cortisol secretion. The cause of dysregulation of steroidogenesis is unknown. The hyperinsulinemia that is compensatory for resistance to the glucose-metabolic effect of insulin seems to have a role in many cases. In most cases, intrinsic intraovarian or intra-adrenal autocrine or paracrine regulatory mechanisms are most likely malfunctioning.

DHEA and DHEA-S: a review

Dehydroepiandrosterone (DHEA) and its sulfated metabolite DHEA-S are endogenous hormones secreted by the adrenal cortex in response to adrenocorticotrophin (ACTH). Much has been published regarding potential effects on various systems. Despite the identification of DHEA and DHEA-S more than 50 years ago, there is still considerable controversy as to their biological significance. This article reviews the metabolism and physiology of DHEA and DHEA-S, the influence of age and gender on concentrations, and changes in endogenous concentrations associated with disease states and other factors, including diet and exercise. This article is unique in that it also summarizes the influence of drugs on DHEA and DHEA-S concentrations, as well as concentrations of DHEA and DHEA-S observed after the administration of DHEA by various routes. Sections of the article specifically address DHEA and DHEA-S concentrations as they relate to stress, central nervous system function and psychiatric disorders, insulin sensitivity, immunological function, and cardiovascular disorders.

Adrenarche results from development of a 3beta-hydroxysteroid dehydrogenase-deficient adrenal reticularis

Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal period. To date, the exact mechanism initiating adrenarche is unknown, although many factors have been postulated. In the present study, we examined the hypothesis that alterations in intra-adrenal expression of 3beta-hydroxysteroid dehydrogenase (3betaHSD) or 21-hydroxylase (CYP21) within the inner reticularis zone leads to the increased production of 19-carbon (C19) steroids. After conversion of cholesterol to pregnenolone, 17alpha-hydroxylase/17,20-lyase (CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3betaHSD competes for substrate with CYP17 and effectively removes steroid precursor from the pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is known to cause excessive production of adrenal C19 steroids, suggesting that CYP21 could play a role in adrenarche. Thus, a decrease in 3betaHSD or CYP21 expression would allow substrate to flow toward the synthesis of DHEA. To determine whether adrenarche results from a decreased expression of 3betaHSD or CYP21 in the reticularis, immunohistochemical localization of 3betaHSD and CYP21 was performed, and staining intensities compared using adrenal glands from children ages 4 months to 4 yr (n = 12), ages 5-7 yr (n = 9), ages 8-13 yr (n = 9), and adults ages 25-56 yr (n = 8). There were no differences in the zonal expression of CYP21. No difference in 3betaHSD staining was observed between the glomerulosa and fasciculata from any age group. However, children age 8 yr and older show a significant decrease in 3betaHSD expression in reticularis as compared with the fasciculata. No significant difference was noted for 3betaHSD levels between the fasciculata and reticularis for children age 7 yr or younger. The level of 3betaHSD expression in the reticularis continued to decrease in the adult adrenals examined. These findings suggest that as children mature there is a decreased level of 3betaHSD in the adrenal reticularis that may contribute to the increased production of DHEA and DHEAS seen during adrenarche.

Androgen response to hypothalamic-pituitary-adrenal stimulation with naloxone in women with myotonic muscular dystrophy

Myotonic muscular dystrophy (MMD) is a disease of autosomal dominant inheritance characterized by multisystem disease, including myotonia, muscle-wasting and weakness of all muscular tissues, and endocrine abnormalities attributed to a genetic abnormality causing a defective cAMP-dependent kinase. We have previously reported that MMD patients demonstrate ACTH hypersecretion after endogenous CRH release stimulated by naloxone administration while manifesting a normal cortisol (F) response. Additionally, others have reported a reduced adrenal androgen (AA) response to exogenous ACTH administration in MMD patients. As ACTH stimulates the secretion of both AAs and F, it is possible that the discordant relationship of these hormones in MMD patients results from a defect of adrenocortical ACTH receptor function or postreceptor signaling or subsequent biochemical events. Furthermore, the molecular abnormality seen in MMD patients may suggest that the mechanism underlying the frequently observed discordances in the secretion of glucocorticoids and AAs (e.g. adrenarche, surgical trauma, severe burns, or intermittent glucocorticoid administration) are explainable solely via an alteration in the function of the ACTH receptor or postreceptor signaling. To ascertain whether the responses of F and AAs to endogenous ACTH diverged in this disorder, we prospectively studied the responses of these hormones to naloxone-stimulated CRH release in nine premenopausal women with MMD and seven healthy age and weight-matched control women. After naloxone infusion (125 micrograms/kg, i.v.), blood sampling was performed at baseline (i.e. -5 min) and at 30 and 60 min. In addition to the absolute hormone level at each time, we calculated the net increment (i.e. change) at 30 and 60 min and the area under the curve (AUC) for F, ACTH, dehydroepiandrosterone (DHA), and androstenedione (A4). Consistent with our previous study, MMD patients demonstrated higher ACTH levels at all sampling times except [minud]5 min. AUC analysis revealed the ACTHAUC values were significantly higher in MMD than in control women (457 +/- 346 vs. 157 +/- 123 pmol/min.L; P < 0.03), whereas the FAUC response did not differ between MMD and controls (13860 +/- 3473 vs. 13375 +/- 3465 nmol/min.L; P > 0.5). Despite the greater ACTH secretion, the baseline circulating dehydroepiandrosterone sulfate levels were significantly lower in MMD compared with control women (18 +/- 23 vs. 61 +/- 23 mumol/L; P < 0.002). The serum concentrations of A4 at baseline, 30 min, and 60 min and DHA levels at 30 and 60 min were also significantly lower in MMD vs. control women. Additionally, the A4AUC and DHAAUC values were significantly lower in MMD patients than in controls. Furthermore, the net response of DHA at 60 min to the endogenous ACTH increase was also reduced in MMD patients compared with that in control subjects (2.3 +/- 2.1 vs. 5.6 +/- 2.6 nmol/L; P < 0.02). In conclusion, in addition to ACTH hypersecretion to CRH-mediated stimuli, these data suggest that MMD patients have a defect in the adrenocortical response to ACTH, reflected in normal F and reduced DHA and A4 secretion. Whether this defect is inherent to the disease or simply reflects adaptive changes to chronic disease remains to be demonstrated. However, it is possible that further studies of the response of MMD patients to ACTH may reveal a mechanism that explains the frequently observed dichotomy in the secretion of glucocorticoids and AAs.

Effect of acute corticotropin releasing factor on pituitary-adrenocortical responsiveness in elderly women and men

Aging is related to critical changes of the hypothalamo-pituitary-adrenal function. A decline in serum DHEA levels has been demonstrated in healthy elderly subjects, while ACTH and cortisol concentrations remain at normal values. The purpose of the present study was to investigate the effect of aging on pituitary-adrenal responsiveness to hCRF in subjects of both sexes. A group of 12 physically and mentally healthy elderly subjects and a group of 12 young controls of both sexes have been selected. Blood samples were collected before and after i.v. bolus injection of hCRF; ACTH, cortisol and DHEA levels were then determined by RIA. Basal ACTH and cortisol levels did not result statistically different between controls and elderly subjects, while DHEA showed a clear and significant age-related decrease (p < 0.01). Following the hCRF injection, the responses of ACTH, cortisol and DHEA in aged subjects were higher than in young controls; ACTH (p < 0.03) and cortisol (p < 0.01) were higher in aged women than in men. The present study demonstrated that aging is associated with an increased responsiveness of ACTH, cortisol and DHEA to exogenous hCRF supply. A hyperactivation of the pituitary-adrenal secretory activity may explain the age-related of the same axis. Gender probably has a significant influence on basal and stimulated hormonal secretion. In conclusion, hCRF test may become a useful clinical tool in establishing a neuroendocrine correlation with central disturbances associated to aging.

A critical review of the origin and control of adrenal androgens

The reticularis and fasciculata zones of the adrenal cortex are the predominant sources of dehydroepiandrosterone (DHEA) and DHEA-sulphate and contribute directly or indirectly 60-75% of androstenedione and testosterone in women. The specific control of adrenal androgens remains unclear. While ACTH stimulates adrenal androgen secretion, the dissociation of cortisol and androgens occurring during adrenarche and under pathological conditions suggests other factors are involved. Recent studies using human adrenal cells in vitro have demonstrated that the ratio of androgen to cortisol produced is substantially independent of the age and gender of the adrenal, indicating that extra-adrenal factors are of greater importance. beta-Endorphin and joining peptide have been shown to stimulate androgen production in human adrenal cells and to influence ACTH-stimulated steroidogenesis in a manner that promotes adrenal androgen production. The activity of these pro-opiomelanocortin-derived peptides may explain the physiological and pathological dissociations of androgens and cortisol.

Effects of guanethidine-induced sympathectomy on the spermatogenic and steroidogenic testicular functions of prepubertal to mature rats

Selective chemical sympathectomy of the internal genital organs of prepubertal to mature male Wistar rats was performed by chronic treatment with low doses of guanethidine. Sympathetic denervation caused an increase in intratesticular progesterone levels in prepubertal and early pubertal rats in addition to a decrease in androstenedione and testosterone levels in prepubertal animals, thus indicating a decrease in the conversion of progesterone into androgen, probably by blocking the steroidogenic enzymatic pathway at the 17 alpha-hydroxylase/17, 20 desmolase level. A lower degree of testicular maturation, probably related to reduced androgen activity, was observed in prepubertal and early pubertal sympathectomized rats. Concentration of spermatozoa, on the other hand, was increased in the enlarged cauda epididymidis of late pubertal and mature denervated animals. This result is discussed in terms of the impairment of epididymal mechanisms of seminal emission, fluid resorption and spermatozoal disposal.

Serine phosphorylation of human P450c17 increases 17,20-lyase activity: implications for adrenarche and the polycystic ovary syndrome

Microsomal cytochrome P450c17 catalyzes both steroid 17 alpha-hydroxylase activity and scission of the C17-C20 steroid bond (17,20-lyase) on the same active site. Adrenal 17 alpha-hydroxylase activity is needed to produce cortisol throughout life, but 17,20-lyase activity appears to be controlled independently in a complex, age-dependent pattern. We show that human P450c17 is phosphorylated on serine and threonine residues by a cAMP-dependent protein kinase. Phosphorylation of P450c17 increases 17,20-lyase activity, while dephosphorylation virtually eliminates this activity. Hormonally regulated serine phosphorylation of human P450c17 suggests a possible mechanism for human adrenarche and may be a unifying etiologic link between the hyperandrogenism and insulin resistance that characterize the polycystic ovary syndrome.

A contribution to the classification of cases of non-classic 21-hydroxylase-deficient congenital adrenal hyperplasia

The aim of this study was to classify the degree of 21 alpha-hydroxylase deficiency in patients suspected for non-classic 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH). In 66 selected subjects (45 young women with polycystic ovary (PCO)-like symptoms and members of their families, of whom 12 were men), progesterone, 17-hydroxyprogesterone (17-OHP) and cortisol were measured at 0, 15, 30, 45 and 60 min after adrenocorticotropic hormone (ACTH) stimulation. The markers [(17-OHP at 30 min--17-OHP at 0 min) + (progesterone at 30 min--progesterone at 0 min)]/30 proposed by Gutai and the ratio of cortisol to 17-OHP at 30 min (cortisol30/17-OHP30) were calculated and cluster analysis was performed using the above two markers and 17-OHP at 60 min (17-OHP60). Our patients were grouped by cluster analysis into four Groups: I, II, III and IV (n = 3, 11, 35 and 16, respectively) with (1) Gutai (mean +/- SE) 107.0 +/- 21.7, 29.9 +/- 4.4, 10.5 +/- 0.54 and 4.0 +/- 0.37 ng/dl per min, respectively, (2) 17-OHP60 169.7 +/- 28.3, 10.8 +/- 1.3, 4.6 +/- 0.2 and 3.7 +/- 0.4 ng/ml, respectively, and (3) cortisol/17-OHP30 0.97 +/- 0.28, 38.5 +/- 6.9, 82.3 +/- 5.5 and 112.0 +/- 8.9, respectively. All three markers showed highly significant differences between the four groups (p < 0.0001). The patterns of 17-OHP, cortisol and cortisol/17-OHP ratio following ACTH testing revealed the degree of 21-hydroxylase deficiency in every group. HLA typing effected in 20 studied individuals confirmed the classification derived from cluster analysis. Thus, it seems that Groups I, II and III include, respectively, patients with severe, mild and minimal forms of non-classic 21-hydroxylase-deficient CAH, while in patients of Group IV the hyperandrogenemic symptoms are of different etiology. In conclusion, the concurrent evaluation of the three markers together with the variations of 17-OHP, cortisol and the cortisol/17-OHP ratio after ACTH testing enhance the accurate identification of a patient suspected for non-classic 21-hydroxylase-deficient CAH in relation to the severity of the enzymatic defect.

Adrenarche does not occur in treated patients with congenital adrenal hyperplasia resulting from 21-hydroxylase deficiency

OBJECTIVE

There have been few studies of adrenarche in patients with congenital adrenal hyperplasia (CAH). We have therefore sought to detect the onset of adrenarche in CAH patients and to investigate whether its evolution was influenced by the severity of the disease, the age at the onset of substitution therapy, or both.

DESIGN AND PATIENTS

Sixteen female CAH patients were studied longitudinally for 4-11 years. They were all given substitution therapy and treatments were well controlled as judged by repeated hormonal evaluations. The patients were divided into two groups: group A consisted of 10 girls with a severe classic (congenital) form, while group B included 6 girls presenting with a non-classic form.

MEASUREMENTS

Circulating levels of dehydroepiandrosterone sulphate (DHEAS), were determined as an indicator of adrenarche. Hormonal assessments included measurements of 17-hydroxyprogesterone (17-OHP), testosterone, ACTH and plasma renin activity. All were estimated by conventional specific assays.

RESULTS

Mean levels were analysed in consecutive two-year age periods. In group A, DHEAS levels were significantly lower at any age than in control subjects, and lower than in patients with non-classic CAH. DHEAS levels showed no increment with age. In group B, plasma DHEAS levels were surprisingly high for the age at the time of diagnosis, declining gradually on substitution therapy, although they remained somewhat higher than in group A.

CONCLUSIONS

The high DHEAS levels observed in untreated girls of group B are probably the result of chronic hypersecretion of ACTH. Under well controlled, non-suppressive substitution therapy, patients with congenital adrenal hyperplasia showed no rise in DHEAS levels at the physiological age of adrenarche whatever the degree of the enzyme defect and whatever the age at onset of therapy.

Hormonal correlates of acne and hirsutism

Acne is a multifactorial disorder reflecting the role of infection, abnormal keratinization and immunologic reaction, as well as hormonal influences, on the pilosebaceous unit. Clinical studies have correlated elevated levels of androgens, originating in both the adrenal glands and ovaries, with acne. These include total and free testosterone, delta 4-androstenedione, dehydroepiandrosterone and its sulfate, and low levels of sex hormone binding globulin. The pathogenesis of acne initiation in childhood has been linked to rising serum levels of dehydroepiandrosterone sulfate. Hirsutism has been more directly correlated with increased levels of serum androgens, notably free testosterone. Underlying causes of elevated androgens in both disorders include very rare tumors, partial or late-onset forms of congenital adrenal hyperplasia, developmental adrenal abnormalities and, most commonly, polycystic ovary syndrome. Early acne treatment may include topical benzoyl peroxide, antibiotics, and tretinoin. More severe disease can be treated systemically (with antibiotics and/or isotretinoin). Very-low-dose corticosteroids can be used to eliminate the adrenal component of hyperandrogenism. Oral contraceptives, especially those that contain low-androgenic progestins, can reduce excessive androgens from any source and specifically suppress the ovary in polycystic ovary syndrome. Gonadotropin-releasing hormone agonists, with or without estrogen supplementation, and systemic or topical antiandrogens may play a more important role in the future.

Oestrogen modulation with parturition in the human placenta

An initial group of term (36-41 6/7 weeks), preterm (less than 36 weeks), and post-term (42 or more weeks) placentae were collected from women at delivery to determine the placental levels of important steroids and steroidogenic enzymes involved in the oestrogen synthesis pathway as a function of gestational age. A second group of placentae were obtained from women delivering at term before and after the onset of labour. Placentae were evaluated individually for cytosolic steroid hormone levels and microsomal steroidogenic enzyme activities. Oestradiol (E2), oestrone (E1), progesterone (P), and delta-4-androstenedione (A) were measured by radioimmunoassay in placental cytosols. Aromatase (AR), sulphatase (S), and 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta HSD) activities were assayed in placental microsomes. Cytosolic concentrations of E1, E2, P, and A did not differ with respect to gestational age. Correspondingly, the microsomal enzyme activities of 3 beta HSD, S, and AR did not vary as a function of gestational age. However, when patients at term who were in labour prior to delivery were compared to those who were not, the placental cytosolic level of E1 was found to be threefold higher in the non-labouring group (4572 versus 1427 pg/mg cytosolic protein, P < 0.025). Additionally, microsomal aromatase activity was also significantly higher in the non-labouring patients (46 versus 19 pM/min/mg protein, P < 0.025), while the E2 to P ratio in the labouring patients was twice that of the non-labouring group, a difference which was significant at the P < 0.025 level (Wilcoxon rank sum test). These data suggest that at term, prior to labour, the placental production of E1 by AR is high, and that AR activity and E1 levels fall significantly after the onset of labour. Also, the placental cytosolic concentration of the more active oestrogen, E2, demonstrates stable to rising levels with a significant increase in E2/P after the onset of labour. We theorize that in the term pregnancy prior to labour, E1 may represent a large but relatively inactive intracellular oestrogen pool which is maintained by high AR activity, and may function to protect the pregnant local uterine environment from the more oxytocic effects of E2.

Androgen biology as a basis for the diagnosis and treatment of androgenic disorders in women. I

Disorders of androgen excess in women are common in the practice of dermatology. The literature regarding the evaluation and treatment of women with cutaneous hyperandrogenism (acne, hirsutism, and alopecia) is vast and is contained in numerous subspecialty journals. At first glance, the basic science knowledge required to understand androgen biology appears exceedingly complex. However, an understanding of androgen physiology and a familiarity with the relevant literature are the basis of appropriate evaluations and treatment recommendations. In the first of this two-part series, we review the basic science of androgen biology and pathophysiology in women. The second part of this series will cover the evaluation of suspected hyperandrogenic women and the therapeutic modalities that are available.

Mechanisms of age-related endocrine alterations. Part II

Aging is associated with a myriad of hormonal changes. The mechanisms underlying these changes are variable. Aging is associated with anatomic changes of the endocrine glands, notably as a result of programmed cell death, autoimmune mediated destruction of the gland, or neoplastic transformation of glandular tissue. Age-related changes in hormonal secretion can also be secondary to physiological changes in circadian and seasonal rhythm, or in frequency or height of hormonal pulses. Some of these changes in hormone secretion are compensatory for the age-related reduction in hormonal clearance, and others are the results of changes in glandular sensitivity to secretagogues or inhibitory stimuli. Age-related changes in hormone action can also be the result of altered bioactivity of hormones, altered transport of hormones to binding receptor sites, altered hormone-receptor interactions or due to postreceptor changes. Within the context of the latter, aging is associated with alterations in plasma membrane properties and intrinsic changes in cellular enzyme activity, and changes in calcium mobilisation and gene expression. Some of these changes are directly related to aging while others are secondary to age-associated diseases and changes in nutritional state. The predominant mechanism in each age-related change varies with the hormone studied. The age-related changes in the mechanisms of endocrine dysfunction are often tissue- and species-specific. Part I of this article discussed the anatomical changes of endocrine glands, changes in hormone secretion, and the changes in the kinetics of hormonal clearance. Part II discusses the changes in hormone action with age.

Investigation of adrenal function in women with oligomenorrhoea and hirsutism (clinical PCOS) from the north-east of England using an adrenal stimulation test

OBJECTIVE

To determine the prevalence of adrenal enzyme dysfunction in women presenting with oligomenorrhoea and hirsutism, two clinical features of polycystic ovary syndrome (PCOS).

DESIGN

A prospective study of women attending outpatient clinics with these complaints. Androstenedione, dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17-OHP), 11-deoxycortisol and cortisol were measured before and after overnight dexamethasone suppression and at 60 minutes after adrenal stimulation by ACTH injection.

SUBJECTS

Fifty women with clinical features of PCOS and 37 control women with regular cycles and normal hair distribution from the catchment area of the Royal Victoria Infirmary which includes Newcastle upon Tyne, Co. Durham, Cleveland, Cumbria and Northumberland.

MEASUREMENTS

Number of women with steroid responses to ACTH beyond the normal range, as defined by the responses of the control group and in previous studies.

RESULTS

Nineteen women (38%) were found to have some abnormality. One woman (2%) was identified with 21-hydroxylase (21-OHase) deficiency and a second (2%) had an increase in 17-OHP compatible with the heterozygote state for 21-OHase deficiency. Four women (8%) had isolated elevations in the DHEA response consistent with minimal 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency. Thirteen women (26%) showed increases in both androstenedione and DHEA, or androstenedione alone, compatible with enhanced 17-20 lyase activity.

CONCLUSIONS

Twelve per cent of the group showed evidence consistent with an adrenal enzyme deficiency; 26% had results in keeping with increased adrenal androgen production without an enzyme deficiency. These findings may be of relevance both in the pathogenesis of the features of PCOS and in determining appropriate treatment for individual patients.

Identification of nonclassical 21-hydroxylase deficiency in girls with precocious pubarche

Recent studies have described mild adrenal enzymatic defects in patients presenting with precocious pubarche. In order to identify these defects we have evaluated basal and ACTH- (25 IU iv) stimulated serum adrenal steroid levels in 19 girls, 2- to 8.3-year-old, with precocius pubarche (pubic hair Tanner II-III). Two patients had clitorial enlargement. Bone age was moderatly advanced in 10 patients and 2 to 3.7 yr in four others. Four patients had high basal serum levels of 17-hydroxyprogesterone (17OHP) (525 + 202 ng/dl, mean +SD), compatible with the diagnosis of nonclassical congenital adrenal hyperplasia due to 21-hydroxylase deficiency (NCCAH-21OH), which was confirmed by an increased response of 17OHP to ACTH (3425 +/- 953 ng/dl). Fifteen patients had moderately elevated basal 17OHP levels (56 + 38 ng/dl) but a normal 170HP response (191 +/- 71 ng/dl) to ACTH, compatible with the diagnosis of idiopathic precocious pubarche (IPP). The cortisol response to ACTH was normal in both groups. Basal values of DHEA-S were 651 +/- 256 and 506 + 462 ng/ml and of DHEA 380 +/- 24 ng/dl and 205 +/- 102 ng/dl, in NCCAH-210H and IPP, respectively. We conclude that: i) clinical findings and baseline levels of DHEA-S and DHEA in IPP can be indistinguishable from the late onset 21 hydroxylase deficiency; ii) baseline levels of 17OHP are sufficient for the diagnosis of NCCAH-21OH; iii) the ACTH stimulation test is indicated only when baseline levels of 17OHP are moderately elevated (100-300 ng/dl).

Hyperandrogenism in peripubertal girls

Androgens arise from either adrenal or ovarian secretion or by peripheral conversion of secreted precursors. The adrenals and ovaries normally contribute about equally to testosterone and AD production. DHAS is the major adrenal 17-KS. Testosterone is the major circulating form of androgen. More than 96% of plasma testosterone is bound to SHBG; the free testosterone seems to be the bioavailable fraction. Hyperandrogenism must be considered in any girl with premature or excessive development of public hair or acne, menstrual irregularity (whether it be oligo-amenorrhea or dysfunctional uterine bleeding), or obesity. The most common cause of premature public hair development (pubarche) is premature adrenarche. The most common cause of hyperandrogenism presenting in a teenage girl is polycystic ovary syndrome. However, the differential diagnosis includes "exaggerated adrenarche," late-onset congenital adrenal hyperplasia, virilizing tumors, Cushing's syndrome, hyperprolactinemia, acromegaly, and abnormalities of androgen action or of metabolism. The plasma free testosterone is a more sensitive indicator of hyperandrogenism than is the total testosterone concentration. The pattern of response of plasma free testosterone, DHAS, and cortisol to dex-suppression testing is diagnostic of the source of androgen excess. Most hyperandrogenic adolescents will be found to have PCOS. The treatment is chosen according to particular symptoms, such as menstrual irregularity, hirsutism, or obesity.

Effects of dihydrotestosterone treatment on adrenal gland function and morphology in adult female guinea-pigs

The effect of chronic treatment of female guinea-pigs with dihydrotestosterone (DHT) on growth and function of the adrenal gland and, in particular, on the reticular zone is described. Two groups of 6 young adult, female guinea-pigs were treated with DHT (1 mg/kg dissolved in peanut oil and injected s.c.) for 30 and 60 days. Two other groups of animals, treated only with oil, were used as controls. At the end of treatment, animals were killed and adrenal glands were quickly removed. Plasma levels of pregnenolone, dehydroepiandrosterone (DHA) and its sulfate (DHA-S), 17 alpha-hydroxyprogesterone, androstenedione, testosterone, estradiol, 11-deoxycortisol, androstenedione, DHT and 3 alpha-androstanediol were determined by R.I.A. following celite microcolumn chromatography. Animals treated for 30 days showed only elevated DHT and 3 alpha-androstanediol plasma levels, whereas animals treated for 60 days also showed increased values of pregnenolone (251 +/- 62 vs 193 +/- 51 ng/dl; P less than 0.05), DHA-S (12,046 +/- 4110 vs 2780 +/- 888 ng/dl; P less than 0.001) and slightly increased values of DHA (110 +/- 31 vs 86.5 +/- 55.4). In the 30-day-treated animals no histological changes were observed, but in the 60-day-treated group the total size as well as cell volumes of the zona reticularis were significantly increased. Normal estrous cycles were observed in the 30-day-treated animals whereas the 60-day-treated animals showed a progressive acyclicity during the second month of treatment. These results indicate that in guinea-pigs, prolonged treatment with DHT induces a growth of the zona reticularis of the adrenal gland associated with increased levels of 5-ene steroids, particularly DHA-S. The mechanisms inducing these modifications are probably mediated by a DHT effect at the hypothalamic-pituitary level. A direct effect of DHT on the zona reticularis, however, cannot be excluded.

Changes in steroid pattern following acute and chronic adrenocorticotropin administration in premature adrenarche

Biochemically adrenarche is characterized by increased production of 5-ene steroids, in particular Dehydroepiandrosterone (DHA) and its sulphate (DHA-S). It is still not clear if ACTH is responsible for this adrenal steroid production. The aim of the present study was to evaluate the effect of acute and chronic ACTH administration, without dexamethasone pretreatment, on hormonal patterns in 20 patients (5 males aged between 6 8/12 and 7 10/12 years and 15 females aged between 5 9/12 and 7 6/12 years) with idiopathic premature adrenarche. Pregnenolone (5P), DHA, DHA-S, 17-hydroxyprogesterone (17-OHP), androstenedione (A), 11-deoxycortisol (S) and cortisol (F) have been determined by Radioimmunoassay. The results of the hormonal evaluation (means +/- standard error) showed high plasma levels of DHA [329.2 +/- 41.7 ng/100 ml (dl)] and DHA-S (169.1 +/- 54 micrograms/dl) and slightly increased levels of 5P (74.4 +/- 7.1 ng/dl), of A (45.4 +/- 4.6 ng/dl) and 17-OHP (69.3 +/- 11.3 ng/dl) in comparison to those of controls, thus indicating a decrease in 3 beta-hydroxysteroid dehydrogenase activity and an increase in 17-20-lyase and 17-hydroxylase activities, characteristic for adrenarche. Acute and chronic ACTH stimulation did not amplify the characteristic basal hormonal pattern, but they induced a shift of adrenal steroid metabolism to 4-ene pathway, suggesting that the basal hormonal pattern in premature adrenarche may be independent or, at least, not exclusively dependent on ACTH control.

Ketoconazole inhibits multiple steroidogenic enzymes involved in androgen biosynthesis in the human ovary

Ketoconazole (KZ) has been shown to inhibit testicular and adrenal steroidogenesis and is useful in the medical management of gonadotropin-independent precocious puberty, prostatic cancer, and Cushing's syndrome. To determine whether KZ similarly affects ovarian steroidogenesis, the authors examined its effect on the activity of the human ovarian 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta-HSD), 17-hydroxylase (17-OH), and aromatase (AR) in vitro. A dose-dependent decrease in the activities of 3 beta-HSD and 17-OH was observed with increasing amounts of KZ. With 10, 50, and 100-fold excess KZ, the activity of 3 beta-HSD decreased by 59% (P less than 0.001), 73% (P less than 0.005), and 85% (P less than 0.005), respectively. At equimolar concentrations with substrate (50 microM), KZ inhibited 17-OH by 70% (P less than 0.01). No significant effect on ovarian AR activity was observed, except at the highest concentration of KZ tested. The authors conclude that low concentrations of KZ profoundly inhibit the activity of human ovarian 3 beta-HSD and 17-OH in vitro. These observations suggest that KZ might be useful in the medical management of women with hyperandrogenism, but further experimentation and clinical trials will be necessary.

The effect of ACTH therapy on serum dehydroepiandrosterone, androstenedione, testosterone and 5 alpha-dihydrotestosterone in infants

Serum concentrations of dehydroepiandrosterone (DHEA), androstenedione, testosterone, 5 alpha-dihydrotestosterone and cortisol were measured in 10 infants (age 5-22 months) before, during and after 6-weeks of ACTH therapy for infantile spasms. During therapy, their mean DHEA concentrations increased 2.3-fold, androstenedione 12.3-fold, testosterone 2.7-fold, 5 alpha-dihydrotesterone 2.5-fold and cortisol 2.9-fold compared to pre-therapy values. Serum dehydroepiandrosterone sulphate (DHEA-S) concentrations were also increased during ACTH therapy above the normal prepubertal range. Three days after the cessation of ACTH treatment, all androgens had returned to the pre-therapy level. We conclude: At least in pharmacologic doses ACTH alone stimulates adrenal androgen secretion in infants, excluding the necessity of a separate adrenal androgen stimulating hormone.

Effect of the antiprogestin RU486 on human ovarian steroidogenesis

Previous studies in the authors' laboratory suggest that the antiprogestin RU486 may directly affect human ovarian progesterone production. The possibility that this compound could affect other steps in human ovarian steroidogenesis was examined by studying its effects on estrogen production in cultured human granulosa cells and on human ovarian aromatase (AR) and 17-hydroxylase (17-OH) activities in vitro. RU486 had no effect on media estradiol (E2) levels as measured by radioimmunoassay (RIA) over a 24-hour incubation period. Furthermore, no effect on ovarian AR activity occurred at concentrations of RU486 100 times substrate. However, a dose-dependent decrease in the activity of 17-OH was observed with increasing amounts of drug. RU486 decreased 17-OH activity by 12 and 29% below that of basal activity at concentrations equal to and ten times substrate. At 50- and 100-fold excess, RU486 further decreased 17-OH activity by 42 (P less than 0.01) and 48% (P less than 0.005). In conclusion, RU486 directly inhibits human ovarian 17-OH activity, but does not affect AR activity or E2 production in vitro. Clinically observed decreases in serum E2 levels may be due to inhibition of enzymatic steps proximal to E2 synthesis. These findings support the authors' previous observations suggesting that RU486 has a direct affect on human ovarian steroidogenesis.