Growth hormone, insulin-like growth factor-I axis, and insulin secretion in hyperandrogenic adolescents**Presented at the 76th Annual Meeting of the Endocrine Society. Anaheim, California, June 15 to 18, 1994.††Supported in part by a grant from Lilly S.A., Madrid, Spain

Long-term metabolic risk among children born premature or small for gestational age

Accumulating evidence suggests that both the intrauterine environment and growth during early life can influence the development of chronic noncommunicable diseases, such as type 2 diabetes mellitus and cardiovascular disease, in adulthood. Here, we review the available human data supporting increased metabolic risk among children born premature or small for gestational age; the adrenal and pubertal modifications that contribute to this risk; metabolic changes that occur during adolescence and early adulthood; and approaches to potentially modify or decrease risk of metabolic disease. The risks associated with delivery at term or preterm are compared for each period of life. Knowledge of these associations is fundamental for the paediatric community to develop preventive strategies early during postnatal life.

Adrenal hyperandrogenism in adolescent girls with a history of low birthweight and precocious pubarche

OBJECTIVE

Girls with precocious pubarche (PP) are at increased risk for ovarian dysfunction, hyperinsulinism and dyslipidaemia in adolescence, in particular when PP is preceded by reduced fetal growth. However, it is not known whether PP girls still have adrenal hyperandrogenism after puberty and if so, which fraction of PP girls develops so-called functional adrenal hyperandrogenism (FAH), an entity characterized by ACTH-dependent 17-ketosteroid excess.

PATIENTS AND DESIGN

Data were longitudinally collected from 47 girls with PP: at birth (weight for gestational age), at diagnosis of PP (age 6.7+/- 1.1 years) and in adolescence (age 15.0+/-1.9 years).

MEASUREMENTS

Serum dehydroepiandrosterone sulphate (DHEAS) and androstenedione were measured at PP diagnosis, as well as the 17-hydroxyprogesterone (17-OHP) response to ACTH; postpubertal evaluation included assessment of adrenal and ovarian function, and of insulin responses to a glucose load. PP girls were considered to have FAH in adolescence if both DHEA and androstenedione responses to ACTH were excessive (> 1500 ng/dl and > 350 ng/dl, respectively).

RESULTS

At diagnosis of PP, girls had high DHEAS and androstenedione levels, as well as high 17-OHP responses to ACTH. In adolescence, PP girls had a normal BMI, presented with mild hirsutism and had high baseline and post-ACTH concentrations of most adrenal androgens, low SHBG levels and tended to have hyperinsulinemia and to present biological signs of ovarian hyperandrogenism. More than a third of the PP cohort developed FAH in adolescence. Neither baseline DHEAS, androstenedione, nor post-ACTH 17-OHP values at diagnosis of PP predicted the development of FAH in adolescence. In PP girls, only a low weight at birth was found to be significantly associated with subsequent FAH.

CONCLUSIONS

These longitudinal findings in girls with PP point to the possibility of an endocrine sequence of prenatal onset: low weight at birth, PP in childhood and adrenal hyperandrogenism in adolescence. The pathophysiological mechanisms underpinning this newly recognized sequence remain to be identified.

Endocrinology and metabolism after premature pubarche in girls

The prevalence of functional ovarian hyperandrogenism, hyperinsulinism and dyslipidaemia is increased in adolescent girls with a history of premature pubarche, defined as the appearance of pubic hair before the age of 8 years. The ovarian hyperandrogenism is characterized by clinical signs of androgen excess and an exaggerated ovarian 17-hydroxyprogesterone response to gonadotrophin-releasing hormone agonist stimulation. The hyperinsulinism and dyslipidaemia are detectable before and during pubertal development, and they are commonly accompanied by low serum levels of insulin-like growth factor binding protein-1 (IGFBP-1) and sex hormone binding globulin, and by an increased prevalence of anovulation from late adolescence onwards. In girls, premature pubarche, hyperinsulinism, low serum levels of IGFBP-1, dyslipidaemia, anovulation and hyperandrogenism (or various combinations of these conditions) have been related to reduced fetal growth, indicating that these constellations or sequences may have a prenatal origin. These findings suggest that premature pubarche in girls should no longer be regarded as merely a normal variant of development, but rather as a childhood marker pointing to an increased risk of a polyendocrine-metabolic disorder of prenatal origin.

Abnormalities in the serum insulin-like growth factor-1 axis in women with hyperandrogenism

OBJECTIVE

To study the insulin-like growth factor-1 (IGF-1) axis in hirsute women.

DESIGN

Controlled clinical study.

SETTING

Tertiary care institutional hospital.

PATIENT(S)

Forty hirsute women and 17 women with normal menstrual cycles.

INTERVENTION(S)

Basal and ACTH-stimulated samples were obtained, and sampling was repeated 1 (gonadal stimulation) and 21 (gonadal suppression) days after a single 3.75-mg IM dose of triptorelin. Controls did not receive triptorelin for ethical reasons.

MAIN OUTCOME MEASURE(S)

Serum GH, IGF-1, IGF-binding protein-3 (IGFBP-3), insulin, glucose, total testosterone, sex hormone-binding globulin, E2, and gonadotropin levels. Basal and ACTH-stimulated steroid precursors were measured.

RESULT(S)

Patients with idiopathic hirsutism were identified by normal serum androgen levels (n=17). Those with functional ovarian hyperandrogenism (n=15) were identified by an increase in the serum testosterone level that normalized during gonadal suppression, whereas those with functional adrenal hyperandrogenism (n=8) were identified by an initial increase in the testosterone level that persisted during gonadal suppression. The adrenal hyperandrogenism group had increased IGF-1 levels compared with the control, idiopathic hirsutism, and ovarian hyperandrogenism groups. Patients with ovarian hyperandrogenism had normal TGF-1 concentrations, but their IGFBP-3 concentrations were lower than those of controls. No differences were observed in GH levels between any of the groups. These results persisted when the influence of age was corrected for.

CONCLUSION(S)

The IGF-1 axis appears to be involved in the pathogenesis of hyperandrogenism, especially in patients with adrenal hyperandrogenism, who have a clear increase in IGF-1 levels. Moreover, patients with ovarian hirsutism have decreased IGFBP-3 concentrations, which might enhance IGF-1 bioavailability.

Premature pubarche, ovarian hyperandrogenism, hyperinsulinism and the polycystic ovary syndrome: from a complex constellation to a simple sequence of prenatal onset

Adolescent girls with a history of premature pubarche have an increased incidence of functional ovarian hyperandrogenism [a form of polycystic ovary syndrome (PCOS)] at adolescence, which is usually associated with hyperinsulinemia and dyslipemia. The hyperinsulinemia and lipid disturbances can often be detected in the prepubertal period and throughout puberty, and are associated with an exaggerated ovarian androgen synthesis. Birthweight SD scores are lower in premature pubarche girls than in control girls, and particularly so in those girls who show hyperinsulinemia and subsequently develop ovarian hyperandrogenism. Therefore, although the mechanisms interlinking the triad of premature pubarche, hyperinsulinism and ovarian hyperandrogenism remain enigmatic, these data indicate that the triad may result, at least in part, from a common early origin, rather than from a direct interrelationship later in life.

Endocrine and metabolic abnormalities in adolescents with a PCOS-like condition: consequences for adult reproduction

The polycystic ovary syndrome (PCOS) has a perimenarcheal onset. Increased luteinizing hormone (LH) and androgen concentrations are common among anovulatory adolescents and some also have hyperinsulinemia. Many will later have normal ovulatory cycles, whereas others with several co-existing abnormalities will develop full-blown PCOS with menstrual cycle irregularities and infertility in adulthood.

Insulin resistance, premature adrenarche, and a risk of the Polycystic Ovary Syndrome (PCOS)

Timing of puberty and final height are usually normal in girls with a history of premature adrenarche. However, these patients show an increased frequency of ovarian hyperandrogenism, hyperinsulinism and dyslipemia at adolescence. The hyperinsulinemia and lipid disturbances can often be detected in the prepubertal period, recommending long-term follow-up of these patients into adulthood.

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

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 = 31], midpubertal [B3; n = 15], late pubertal [B4; n = 12], and postmenarcheal [B5; n = 18]) and 45 controls.

INTERVENTION(S)

Gonadotropins and plasma steroid hormones (17-OHP, 17-OH-pregnenolone [17-Preg], androstenedione [A], T, DHEA, DHEAS, E2, and cortisol) were measured before and 3 and 24 hours, respectively, after LA challenge (500 micrograms 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 E2 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 17 alpha-hydroxylase and the 17,20 lyase functions of cytochrome P450c17 alpha.

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.