girls diagnosed with premature pubarche show an exaggerated ovarian androgen synthesis from the...

FERTILITY AND STERILITY@ Copyright v 1997 American Society for Reproductive Medicine

Published by Elsevier Science Inc.

Vol. 67, No. 5, May 1997 Printed on acid-free paper in Cl. S. A.

Girls diagnosed with premature pubarche show an exaggerated ovarian androgen synthesis from the early stages of puberty: evidence from gonadotropin-releasing hormone agonist testing*t

Lourdes Ibariez, M.D.@ Neus Potau, M.D.11 Maria Zampolli, M.D.1

Maria E. Street, M.DI Antonio Carrascosa, M.D.3

Hospital Materno-Znfantil Vu11 d’Hebron, Autonomous University of Barcelona, Barcelona, Spain, and Clinica Pediatrica,

University of Parma, Parma, Italy

Objective: To assess the gonadotropin and ovarian steroid responses to the GnRH agonist (GnRH-a) leuprolide acetate (LA) in premature pubarche girls and in Tanner stage- and bone age-matched controls to ascertain whether the ovarian 17-hydroxyprogesterone (17-OHP) hyper- response to GnRH-a challenge present in some subsets of adolescent premature pubarche girls is detectable during puberty and whether these patients have a distinct pattern of pituitary- ovarian maturation.

Design: Cross-sectional study. Setting: A university teaching hospital. Patient(s): Seventy-six premature pubarche girls (early pubertal [B2; n = 311, midpubertal

[B3; n = 151, late pubertal [B4; n = 121, and postmenarcheal [B5; n = 181) and 45 controls. Intervention(s): Gonadotropins and plasma steroid hormones (17-OHP, 17-OH-pregneno-

lone [17-Preg], androstenedione [A], T, DHEA, DHEAS, Ez, and cortisol) were measured before and 3 and 24 hours, respectively, after LA challenge (500 pg SC).

Main Outcome Measure(s): Ovarian-steroidogenic responses to GnRH-a challenge. Result(s): Luteinizing hormone responsiveness increased significantly during puberty in all

subjects whereas FSH levels changed less consistently. Peak Ez levels differed among pubertal stages and were significantly higher in premature pubarche girls than in controls at B4 and at B5. Both peak and incremental increases of 17-Preg and DHEA throughout puberty and of 17- OHP and A at B4 were significantly higher in premature pubarche girls than in controls. This pattern of ovarian-steroidogenic response was most evident during midpuberty and late puberty and resembled the adrenal hyper-response to ACTH of exaggerated adrenarche, suggestive of increased ovarian activity of both the 17o-hydroxylase and the 17,20 lyase functions of cytochrome P450c17a.

Conclusion(s): Pubertal girls with a history of premature pubarche show a distinct pattern of ovarian maturation characterized by an exaggerated ovarian androgen synthesis throughout puberty. (Fertil Steril@ 1997;67:849-55. 0 1997 by American Society for Reproductive Medicine.)

Key Words: Premature pubarche, ovarian steroid hyper-responsiveness, GnRH-a testing, ovarian cytochrome P45Oc17a dysregulation

Elevated plasma 17-hydroxyprogesterone (17- OHP) responses and a lesser hyper-responsiveness

Received August 9, 1996; revised and accepted December 5, 1996.

* Supported in part by a Visiting European Society for Paediat- ric Endocrinology Scholarship Grant.

t Presented at the 77th Annual Meeting of the Endocrine Soci- ety, Washington, D.C., June 14 to 17, 1995.

$ Adolescent and Endocrine Unit, Hospital Materno-Infantil Vall d’Hebron, Autonomous University of Barcelona.

of androstenedione (A) to GnRH agonist (GnRH-a) challenge are found in approximately two thirds of women with chronic hyperandrogenism and oligomenorrhea, often without customary criteria for the

0 Reprint requests: Lourdes Ibaiiez, M.D., Adolescent and En- docrine Unit, Hospital Materno-Infantil Vall d’Hebron, P. Vall d’Hebron, 119-129,08035 Barcelona, Spain (FAX: 34-3-4283210).

// Hormonal Laboratory, Hospital Mater-no-Infantil Vall d’He- bron, Autonomous University of Barcelona.

1 Clinica Pediatrica, University of Par-ma.

0015-0282/97/$17.00 PI1 SOO15-0282(97)00024-l

849

diagnosis of polycystic ovary syndrome (PCOS) (l- 3). This pattern of ovarian-steroidogenic response, defined as functional ovarian hyperandrogenism, is part of the spectrum of PCOS (11, and appears to be particularly frequent in hyperandrogenic adolescents (4).

It has been postulated that the abnormality in functional ovarian hyperandrogenism involves dysregulation of ovarian androgen and estrogen secretion (2, 3, 5). Dysfunction of individual thecal cells escaping from down-regulation of steroidogenesis, predominantly at the level of the 17-a-hydroxylase and 17,20 lyase activities of cytochrome P45Oc17c~, would result in overactive steroidogenesis (2, 3, 5). As ovarian hyperandrogenism has been described in perimenarcheal girls, it has been suggested that primary dysregulation of androgen secretion may be of pubertal onset (6).

Postpubertal girls with a history of premature pubarche, defined as the appearance of pubic hair before 8 years, have an increased frequency of functional ovarian hyperandrogenism (45% versus 3% in the normal population [71). The entity seems to occur more frequently in girls with elevated DHEAS and/ or A levels at premature pubarche diagnosis (7). However, whether the 17-OHP hyper-response typical of functional ovarian hyperandrogenism is detectable during puberty in premature pubarche girls and whether they have a distinct pattern of pituitary-gonadal maturation remains unknown.

Therefore, we undertook the present study to assess whether girls with a history of premature pubarche also have an exaggerated gonadotropin and ovarian androgen secretion throughout puberty compared with normal girls. Because, to our knowledge, no data on pituitary-ovarian responses to GnRH-a stimulation in normal pubertal girls have been reported, this study also could provide normative data on the patterns of pituitary-ovarian maturation.

MATEIRIALS AND METHODS

Subjects Hormonal Assays

Seventy-six premature pubarche girls 8.9 to 18 years of age and 45 bone age-matched controls (9.7 to 17 years) were studied. Subjects were divided into four groups according to their Tanner stage of breast development (8): early pubertal (B2), midpubertal (B3), late pubertal (B4), and postmenarcheal (B5). At the time of study, ~6 months had elapsed since the onset of pubertal signs in all subjects. All girls in groups B2 to B4 were premenarcheal. In all patients, premature pubarche was secondary to premature adrenarche, namely, they presented with elevated A and/or DHEAS at premature pubarche diagnosis (9).

Luteinizing hormone and FSH were measured using a commercially available microparticle enzyme immunoassay (IMX System; Abbott, Chicago, IL). The intra-assay and interassay CVs were 3.0% and 5.4%, respectively, for LH and 4.1% and 6.9%, respectively, for FSH. The DHEA was assayed using a tritiated kit (ICN Biomedical, Inc., Carson, CA). The intra-assay and interassay CVs were 7% and 14%, respectively. After ethyl-acetate-hexane (3:2) extraction and Celite column chromatography, 17- OH-Preg was determined by RIA with 3H-labeled standard and antibody provided by ICN Biomedical.

Late-onset congenital adrenal hyperplasia was ruled out in all subjects before their inclusion in the study by means of an ACTH test (10, 11).

None of the subjects was hirsute, according to the Ferriman and Gallwey score (12), and none had menstrual irregularities, such as oligomenorrhea (menstrual cycles of >45 days duration) or amenorrhea suggestive of functional ovarian hyperandrogenism. Postmenarcheal girls were studied in the follicular phase (days 3 to 8) of the menstrual cycle. The baseline clinical characteristics of all groups and the adrenal androgen levels of patients at the diagnosis of premature pubarche are depicted in Table 1.

The protocol was approved by the Institutional Re- view Committee at the Barcelona hospital. The pur- pose of the study was explained to all subjects before participation. Informed consent from patients or from their parents was obtained, as well as assent from minors.

Study Protocol

Baseline blood samples were obtained between 8:00 and 10:00 A.M. in the fasting state and in supine position for measurement of plasma steroid hormones (17-OHP, 17-hydroxypregnenolone [17-Pregl, A, T, DHEA, DHEAS, Ez, and cortisol), and gonadotropins. Leuprolide acetate (500 pg SC LA, Procrin; Abbott, Madrid, Spain) then was administered, and blood samples were drawn 3 hours and 24 hours after challenge for gonadotropin and steroid hormone measurements, respectively. The timing of blood sampling was selected according to previously reported data indicating that maximal pituitary and gonadal stimulation occur 3 to 4 hours and 20 to 24 hours, respectively, after GnRH-a administration (4, 7,131. To rule out the possibility of coincidental adrenal androgen secretion occurring during the test, plasma cortisol levels also were determined at 24 hours. The samples were centrifuged immediately, and serum was separated and frozen at -20°C until assayed.

850 IbAiiez et al. Ovarian steroids in premature pubarche Fertility and Sterility@

Table 1 Clinical Characteristics of Subjects and Adrenal Androgen Levels in Patients at Diagnosis of Premature Pubarche”

B2t B3 B4 B5

PPS (n = 31) (n =” 15) (n cp15) (n 2 11) (n rp12) (n =” 10) (n rp18) (nC 9)

Age (Y) 9.8 + 0.1 11.2 + 0.3 11.0 ? 0.2 12.5 k 0.3 12.0 ? 0.4 13.1 2 0.4 15.4 2 0.6 15.7 -c 0.3 Bone (y) age 10.9 k 0.1 10.8 2 0.1 12.3 2 0.1 12.1 2 0.2 13.2 2 0.2 13.3 ? 0.1 15.0 k 0.2 15.3 2 0.1 BMI (kg/m’) 18.5 ? 0.511 16.5 5 0.3 19.4 2 0.99 17.5 2 0.4 20.0 2 0.9 19.6 ? 0.9 22.5 k 0.6 22.7 2 1.0 Puberty onset

(Y) 9.5 2 0.1 11.0 + 0.3 9.6 t 0.2 10.9 2 0.3 9.7 2 0.2 10.8 2 0.3 9.8 t 0.3 10.8 + 0.2 Menarche (y) Basal A (r&K)! 104.6 _ 8.5tt

- - : 9.6** ??

12.0 t 0.2 12.9 2 0.3 - 116.5 5 14.3t-F - 115.4 99.8 ? 10.8t.t -

Basal DHEAS (/&dL)1 143.1 +- 6.5tt - 161.4 2 5.1** - 118.4 2 4.9tt - 138.6 2 7.9tt -

Post-ACTH 17- OHP (ng/dL)l 251.1 2 23.1 - 237.9 2 42.6 - 236.8 ? 36.8 - 252.1 2 33.0 -

* Values are means -t- SE. To convert units to nmol/L, multiply 11 P < 0.002 versus controls. the concentrations of each hormone by the following factors: A, 1 Normal reference values for prepubertal girls (n = 50): A, 68.7 0.0349; 17-OHP, 0.03026. To convert DHEAS values to PmoUL, 2 2.8 ng/dL; DHEAS, 36 2 13 &dL; and post-ACTH 17-OHP, multiply by 0.02714. 198.2 t 85.9 ng/dL.

t B2 to B5 are Tanner breast stages II through V. 3 PP, premature pubarche. $ P < 0.01 versus controls.

**P = 0.01 versus normal values. tt P = 0.02 versus normal values.

Cortisol, Ez, T, 17-OHP, and DHEAS were measured by direct RIA using commercially available kits (cortisol, Immunotech SA, Marseille, France; Ez, T, and DHEAS, Diagnostics Products Corp., Los Angeles, CA, 17-OHP, Pantex, Santa Monica, CA). Andro- stenedione was measured by RIA (Immunotech SA) with previous dichloromethane extraction. The intra-assay and interassay CVs were as follows: cortisol, 6.5% and 7.7%; Ea, 4% and 7%; T, 9.2% and 10.4%; A, 6% and 11.9%; 17-OHP, 3.8% and 10.6%; and DHEAS, 5.3% and 3.9%, respectively. All hormone determinations in each individual were measured in duplicate within a single assay.

when analyzed by ANOVA (P ratio = 3.1 to 21.7; P < 0.001).

Leuprolide acetate stimulated LH release in all study groups. Both ALH and peak LH responses 24 hours after GnRH-a challenge rose during puberty (F ratio = 9.7 to 27; P < 0.0001). Peak LH values were significantly higher in premature pubarche girls at B4 to B5 than at B2 (P < 0.001 and P < 0.001, respectively). Likewise, controls had higher peak LH levels at B5 than at B2 (P < 0.01) (Fig. 1).

The increase in baseline FSH levels during puberty was significant only for premature pubarche girls (F ratio = 4.9; P < 0.003) (Fig. 1). The GnRH-a

Statistical Analysis

Auxological data and hormonal results are expressed as the mean ? SE unless otherwise stated. Hormone data are expressed as baseline, peak, and increase (A), defined as the difference between the peak value after stimulation and the baseline level. Hormone levels among independent groups were compared by one-way analysis of variance (ANOVA) followed by Scheffe’s test for multiple comparisons. All P values are two tailed. P values < 0.05 were considered significant. Correlations were examined by linear regression analysis.

RESULTS

Gonadotropins

Baseline LH levels rose during puberty (Fig. 1). Differences among Tanner stages were significant

Figure 1 Baseline and peak gonadotropin levels after LA administration in patients and controls in early puberty (B2), midpuberty (B3), late puberty (B4), and postmenarche (B5). Values are means t SE. tP < 0.05 versus controls; t;P < 0.006 versus patients.

Vol. 67, No. 5, May 1997 Ibki%ez et aI. Ovarian steroids in premature pubarche 851

A5 -pathway

Figure 2 Baseline and peak A5-steroid levels after LA challenge in patients and controls in early puberty (B2), midpuberty (B3), late puberty (B4), and postmenarche (B5). Values are means t SE. tP < 0.001; $P < 0.03; $P < 0.0001; ilp < 0.003; !I’ < 0.02; **I’ = 0.0007; PtP = 0.006, and $$P < 0.04 versus controls.

administration stimulated FSH release in all groups tested. The AFSH and peak FSH responses were different among pubertal stages for patients (F ratio = 5; P < 0.003) but not for controls.

Comparison of Premature Pubarche to Controls

Basal LH levels were similar between patients and controls within the same stage of pubertal development except at B4, where premature pubarche girls showed higher LH concentrations (P < 0.05). Controls showed higher ALH and peak LH responses at B2 (P < 0.008 and P < 0.006, respectively) (Fig. 1). Differences in ALH and peak LH responses between patients and controls at B3, B4, and B5 did not reach statistical significance. No differences in AFSH and peak FSH values between patients and controls within the same pubertal stage were observed (Fig. 1).

Steroids

Basal levels of all steroid intermediates rose significantly during puberty (F ratio = 4.0 to 19.7; P < O.OOl), except A and 17-OHP in controls. All steroids at baseline were lower at B3 than at B4 to B5 except for 17-Preg, 17-OHP, and A in controls (Figs. 2 and 3). Most steroids increased significantly in response to IA, except DHEAS and T (Figs. 2 and 3). Patients showed higher peak DHEA, DHEAS, 17- OHP, A, and T concentrations at B4 than at B2. In controls, these differences were only significant for DHEA, DHEAS, and A (F ratio = 3.9 to 20.9; P < 0.001). Maximal DHEA, DHEAS, and T values were reached at B5 in all subjects, whereas the high-

est 17-Preg, 17-OHP, and A levels occurred at B3 in controls and at B4 to B5 in patients (Figs. 2 and 3).

Baseline Ez levels increased during puberty (F ratio = 3.9 to 9.7; P < 0.001) (Fig. 3). Peak E2 levels after LA challenge differed significantly among pubertal stages @‘ratio = 3.9 to 21.2; P < 0.001). Basal cortisol levels were similar in all subjects regardless of the pubertal stage, as expected, and showed no increment after LA challenge (pooled data: 16.3 ? 1.5 versus 15.7 + 1.2 ,ug/dL, respectively).

Comparison of Premature Pubarche to Controls

A5-Pathway

Patients had significantly higher basal 17-Preg, DHEA, and DHEAS at B2 (P < 0.001, P < 0.03, and P < 0.0001, respectively); higher DHEA and DHEAS at B4 (P < 0.003 and P < 0.02, respectively); and higher DHEAS at B5 (P < 0.02) (Fig. 2). Similarly, patients showed higher peak levels of 17-Preg at B2, B4, and B5 (P = 0.0007, P = 0.006, and P < 0.04, respectively); of DHEA at B2, B3, and B4 (P < 0.003, P < 0.003, and P < 0.001, respectively); and higher DHEAS values after GnRH-a challenge at all Tan- ner stages (P = 0.0007, P < 0.04, P < 0.02, and P < 0.02 for B2, B3, B4, and B5, respectively) (Fig. 2).

A4-Pathway

Patients had significantly higher basal 17-OHP, A, and T levels at B4 (P < 0.001, P < 0.04, and P < 0.001, respectively) and higher basal A and T levels at B5 (P < 0.02 and P < 0.001, respectively). Likewise, patients showed higher peak levels of 17- OHP at B4 (P = 0.0007>, of A at B4 and at B5 (P

t

Figure 3 Baseline and peak A4-steroid levels after LA challenge in patients and controls in early puberty (B2), midpuberty (B3), late puberty (B4), and postmenarche (B5). Values are means ? SE. iP < 0.001; $p < 0.04; $P < 0.02; jlp = 0.0007, and ljP = 0.006 versus controls.

862 Ibtiez et al. Ovarian steroids in premature pubarche Fertility and Sterility”

Figure 4 Incremental rises (A) of 17-Preg, DHEA, 17-OHP, and A after LA challenge in the study groups at the different Tanner stages. Values are means t SE. tP = 0.001; $P < 0.01; §P = 0.0003, and lip = 0.03 versus controls.

= 0.006 and P < 0.04, respectively), and higher maximal T values at B4 and at B5 (P < 0.001 and P = 0.006, respectively) (Fig. 3).

Basal Ez levels were similar in patients and controls, whereas peak E2 concentrations were significantly higher in premature pubarche girls at B4 and at B5 (P < 0.02 and P < 0.04; respectively) (Fig. 3). Incremental rises of steroid intermediates after the agonist were significantly higher in premature pubarche girls than in controls for 17-Preg from B3 to B5 (P = 0.001, P < 0.01, and P = 0.0003, respectively), for DHEA at B2 and B4 (P < 0.01 and P < 0.01, respectively), and for 17-OHP and A at B4 (P = 0.03 and P = 0.03, respectively) (Fig. 4).

Correlations

Peak and incremental LH responses and baseline and peak DHEA, DHEAS, and T responses to LA showed a better correlation with bone age (r = 0.45 to 0.6; P < 0.0001) than with body mass index in all subjects (r = 0.36 to 0.4; P < 0.001).

DISCUSSION

The present study was conducted to assess whether an exaggerated ovarian 17-OHP response suggestive of functional ovarian hyperandrogenism could be detected during puberty in premature pubarche patients and whether they had a distinct pattern of pituitary-ovarian maturation. The study also examined the patterns of pituitary-ovarian secretion during normal puberty.

Our results indicate that pubertal premature pubarche girls have an exaggerated ovarian androgen synthesis beginning at the early stages of pubertal development and most evident during midpuberty

Vol. 67, No. 5, May 1997

and late puberty. It is characterized by higher basal, peak, and incremental responses of most steroid intermediates to LA challenge.

Luteinizing hormone responsiveness increased significantly during puberty both in patients and controls, whereas changes in FSH levels were less striking. Our results confirm previous studies per- formed with nafarelin in normal males, which demonstrate that GnRH-a stimulate gonadotropin release during puberty, with the responsiveness of LH increasing with pubertal stage, and FSH responses changing less consistently with pubertal maturation (14).

Both peak LH and LH increases after the agonist showed a better correlation with bone age than with the body mass index, as expected from previous studies (15), suggesting that bone maturation is a good parameter for predicting pubertal progression when puberty has been established for some time. Maxi- mal Ez levels were detected at B4 and declined at B5 together with an increase in gonadotropin responsiveness. This can be explained by the fact that all subjects in group B5 were postmenarcheal and purposely were studied during the follicular, and thus, low estrogen phase of the menstrual cycle, in order to minimize the physiological increase in androgen secretion occurring during the late follicular and luteal phases. The higher peak E2 responses to GnRH-a challenge observed in patients at B4 and B5 could be mediated in part by the increase in LH- induced A synthesis, which in turn would permit the aromatization of more Ez by the granulosa cell.

Patients showed higher T and DHEAS levels after GnRH-a challenge compared with controls at most pubertal stages tested. However, their incremental increases were similar, because they started from a higher baseline, which could be both adrenal and ovarian in origin. In contrast, both peak and incremental increases of 17-Preg and DHEA throughout puberty, peak and incremental increases of 17-OHP and A at B4, and peak A at B5 were significantly higher in premature pubarche girls than in controls, suggesting increased ovarian 17cY-hydroxylase activity both in the A4 and A5-pathway, and increased 17,20 lyase activity in the A5-pathway.

As previous studies have found no differences in the response to GnRH-a with or without adrenal suppression, it is unlikely that the absolute increases of the steroid intermediates after challenge could be influenced by adrenal secretion (16). More- over, coincidental adrenal secretion occurring by chance during the test in response to stress can be ruled out, as basal and after challenge cortisol levels were very similar.

This pattern of ovarian-steroid responsiveness resembles an exaggeration of the adrenal secretory re-

Ibhiiez et al. Ovarian steroids in premature pubarche 853

sponses to ACTH characteristic of adrenarche (17). During adrenarche, there are striking increases in 17-Preg and DHEA responsiveness to ACTH, which appear to be due to maturational increases in both 17a-hydroxylase and 17,20 lyase activities, both functions of cytochrome P45Oc17a (17). Exaggerated adrenarche is common in hirsute women, hyperandrogenic adolescents, and prepubertal premature pubarche children (4, 18, 19). This entity might prominently but not exclusively be due to dysregulation of cytochrome P450c17a activity of the same sort that seems to coexist in functional ovarian hyperandrogenism patients. It has been suggested that, in premature pubarche girls with functional ovarian hyperandrogenism, dysregulation of cytochrome P450c17a might begin in the adrenal during childhood, cause premature pubarche development, and subsequently occur in the ovary, provoking fimc- tional ovarian hyperandrogenism (7).

The hyper-responses of most steroid intermediates to GnRH-a stimulation present throughout puberty appeared to subside after its completion, with the exception of 17-Preg. However, peak 17-Preg levels, baseline and peak A levels, and DHEAS and T concentrations before and after GnRH-a challenge con- tinued to be higher in patients than in controls at B5. Although all patients had a history of premature pubarche, they did not show other clinical signs or symptoms suggestive of androgen excess. However, it is possible that more prolonged androgen exposure is required before development of consequences such as hirsutism or oligomenorrhea.

Ovarian androgens are known to be potent atre- togenic agents (20). Excess androgen formation normally seems to be prevented primarily by a down- regulation process whereby excessive LH stimulation leads to desensitization of the intraovarian responses to LH. Androgen and estrogen appear to inhibit this response by short-loop (intracrine-para- crine) negative feed-back at the level of 17a-hydroxylase-17,20 lyase (2). These inhibiting modulators may be counterbalanced by hormones and growth factors that amplify 17a-hydroxylase-17,20 lyase activities, such as insulin-like growth factor-l (IGF-1) and insulin (21). In addition, hyperinsulinemia, by acting through the IGF-1 ovarian receptors or hybrid insulin-IGF-1 receptors, synergizes with LH in stimulating excessive androgen production by ovarian- thecal cells (21, 22) and also enhances LH-stimulated steroid accumulation in granulosa cell cultures (23). Hyperinsulinemia also may precipitate hyper- androgenemia by acting as a second hit to unmask latent abnormalities in the regulation of adrenal and ovarian steroidogenesis (24). Both hyperinsulinemia and elevated IGF-1 levels are common features in premature pubarche girls before the onset of puberty

(Ibafiez et al, personal communication). Further- more, adolescent premature pubarche patients with functional ovarian hyperandrogenism and one third of premature pubarche girls who do not develop functional ovarian hyperandrogenism show hyperinsulinemia compared with normal adolescents (25). Thus, it is tempting to speculate that, in pubertal premature pubarche girls, increased intraovarian androgen secretion can be triggered by both the gen- eralized overactivity of thecal steroidogenesis present in these patients from early puberty (as indi- cated by their increased steroid responses) and by the increased insulin and/or IGF-1 levels, which may potentiate modulators of LH action within the ovary.

The major abnormalities in functional ovarian hyperandrogenism occur in the A4-pathway beyond progesterone (2>, but subtle parallel changes also are present in the A5-pathway. Abnormal regulation of 3P-HSD and the preceding steroidogenic steps could account for the observed steroid pattern of functional ovarian hyperandrogenism (3). Thus, in premature pubarche girls, the ovarian-steroidogenic abnormalities initially would be most prominent in the A5- pathway and in some susceptible individuals, subsequently predominate in the A4-pathway, giving the pattern typical of functional ovarian hyperandrogenism.

In summary, pubertal girls diagnosed with premature pubarche during childhood demonstrate increased peak and incremental responses of most steroid intermediates to GnRH-a stimulation suggestive of abnormal regulation of cytochrome P450c17a. This resembles the adrenal hyper-response to ACTH typical of exaggerated adrenarche and is detectable as early as B2 though is most evident during the midpubertal and late pubertal stages. In some subsets of patients in which genetic or environmental predisposing factors coexist, disor- dered regulation of the cytochrome P450c17a might persist postpubertally, leading to the clinical and biochemical pattern typical of functional ovarian hyperandrogenism. These results are in agreement with previous studies supporting a pubertal onset of functional ovarian hyperandrogenism and indicate the need for a routine postpubertal follow-up of premature pubarche patients.

Achnozoledgment. We are indebted to Ann E. Taylor, M.D., Na- tional Center for Infertility Research and the Reproductive Endo- crine Sciences Center, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, for reviewing the manuscript.

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girls diagnosed with premature pubarche show an exaggerated ovarian androgen synthesis from the...

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