Hormonal findings in African-American and Caribbean Hispanic girls with premature adrenarche: implications for polycystic ovarian syndrome.

BACKGROUND: Premature adrenarche refers to the early maturation of the adrenal zona reticularis such that the resultant modest hyperandrogenism causes the early appearance of pubic hair before the age of 8 years in girls and 9 years in boys. The precise etiology of premature adrenarche is not known. However, recent studies indicate that certain girls with premature adrenarche are at risk of developing functional ovarian hyperandrogenism, polycystic ovarian syndrome, and hyperinsulinism. Caribbean Hispanic women in general are at increased risk of developing polycystic ovarian syndrome, and African-Americans are at increased risk of developing the complications of hyperinsulinism. Previously, girls with premature adrenarche were reported to have androgens in the range found in normal children in the early stages of puberty. We noted that many of our African-American and Caribbean Hispanic patients with premature adrenarche had androgens that were much higher than what has been reported previously. OBJECTIVE: This retrospective study was performed to characterize the adrenocorticotropin-stimulated androgen response in an African-American and Caribbean Hispanic population of girls with premature adrenarche. METHODOLOGY: The androgen response to adrenocorticotropin stimulation in 72 African-American and Caribbean Hispanic girls with premature adrenarche was compared with those reported for normal girls in early puberty (Tanner stages II and III). The mean age was 6.8 +/- 0.8 years, bone age was 8 +/- 1.5 years, pubic hair was Tanner stages II and III, and body mass index was 18.6 +/- 4. RESULTS: Of the girls, 28% were found to have elevated stimulated 17OHPregnenolone (17OHPreg) levels that were >2 SD units above the mean for normal early pubertal children. The stimulated ratio of 17OHPreg/17OHProgesterone also was elevated in 18% of the girls and showed a modest correlation with body mass index. CONCLUSION: In contrast to previous studies of girls of mixed ethnic backgrounds with premature adrenarche, 28% of the 72 African-American and Caribbean Hispanic girls with premature adrenarche had adrenocorticotropin-stimulated 17OHPreg levels that were significantly higher than those seen in early pubertal girls. Because 17OHPreg hyperresponsiveness has been described previously in women with hirsutism or polycystic ovarian syndrome, the similar finding in many African-American and Caribbean Hispanic girls with premature adrenarche suggests that the two conditions may share a common mechanism for their hyperandrogenism. Therefore, the hyperandrogenism in certain African-American and Caribbean Hispanic girls with premature adrenarche may not be benign and may be the first presentation of polycystic ovarian syndrome.

Phallic growth after hCG. A clinical index of androgen responsiveness.

Clinical and hormonal responses to a standard three-day human chorionic gonadotropin (hCG)-stimulation test (1,500 IU given intramuscularly for three days) were studied in six neonates with ambiguous genitalia. All patients were eventually determined to be 46,XY genetic males with a microphallus and various other genital abnormalities. None had an enzymatic defect in steroidogenesis or a 5 alpha-reductase deficiency, as determined by standard adrenocorticotropic hormone (ACTH) and hCG testing. All patients demonstrated penile growth (0.25 to 0.75 cm) within five days of hCG administration, with four of six patients achieving a normal penile length (> 2.0 cm) by 48 hours after the last of three daily hCG injections. Androgen responsiveness suggested by phallic growth may help support a male sex assignment in such infants.

Cortisol production rate in childhood and adolescence.

We studied the daily cortisol production rate in 33 normal children and adolescents, using a stable isotope-dilution technique employing high-performance liquid chromatography-mass spectrometry. Two indwelling intravenous catheters were inserted and tracer 9,12,12-2H3-cortisol (deuterated cortisol) was infused continuously for 30 hours. After 6 hours of tracer infusion to allow for equilibration, blood was obtained every 20 minutes for 24 hours. The mean (+/- SD) cortisol production rate was 9.5 +/- 2.5 mg/day (6.8 +/- 1.9 mg/m2/day). Cortisol production rate did not vary with sex or pubertal stage. These results suggest that the cortisol production rate in children and adolescents is significantly lower than previously estimated.

Studies on the mechanism of the inhibition of platelet aggregation and release induced by high levels of arachidonate.

We have previously reported that arachidonic acid induced a biphasic pattern of platelet aggregation and the release of both dense and alpha-granule components. Low levels of arachidonate (0.025--0.1 mM) specifically induced aggregation and release, while high concentrations (0.15--0.35 mM) caused a progressive inhibition of these platelet responses in human gel-filtered platelets (GFP). We now report studies of the mechanism(s) responsible for this arachidonate-induced turn-off of platelet function. Electron micrographic studies demonstrated that there was no gross damage to the platelets during the turn-off. Active synthesis of malondialdehyde and thromboxane A2 was seen at the high arachidonate levels, despite the inhibition of aggregation. Furthermore, GFP inhibited by 0.25 mM arachidonate were capable of undergoing aggregation and serotonin release in response to other stimuli, such as collagen or thrombin. Thus, GFP appeared to be metabolically intact and functional during the inhibiton by high arachidonate levels. Thin-layer chromatographic studies revealed that prostaglandin metabolism was not changed at the high arachidonate levels. In addition, indomethacin (20 microM) did not abolish the arachidonate-induced inhibition of platelet function. Therefore, the inhibitory effect of high arachidonate did not depend on its conversion to other prostaglandin products. Platelet cyclic AMP levels increased twofold at the high arachidonate concentrations (1.3 +/- 0.3 pmole/10(8) platelets at peak aggregation, compared with 2.9 +/- 0.4 pmole/10(8) platelets at inhibition by 0.25 mM arachidonate, p less than 0.001). Prostaglandin-D2, a platelet inhibitor known to increase cyclic AMP, generated a similar rise (to 2.4 +/- 0.2 pmole/10(8) platelets). Thus, the magnitude of the arachidonate-induced increase in platelet cyclic AMP levels can account for the inhibition of aggregation and release.

Release of platelet-derived growth factor from human platelets by arachidonic acid.

Platelet alpha-granules contain a factor that stimulates the proliferation of arterial smooth muscle cells and may play a role in atherogenesis. We have studied the role of arachidonic acid in mediating the release of the platelet-derived growth factor (PDGF) from human platelets. PDGF was assayed by stimulating of [(3)H]thymidine incorporation into DNA of mouse 3T3 cells. Platelet aggregation and the release of platelet factor 4,beta-thromboglobulin, and serotonin were also studied. A biphasic response pattern was observed when gel-filtered platelets were incubated with arachidonate over the concentration range 0.01-0.4 mM. At low arachidonate levels (approximately 0.025-0.1 mM), specific concentration-dependent aggregation and release of PDGF and of the other components were observed. This effect was not seen with any of five other fatty acids tested and was suppressed by indomethacin (25 muM). At higher arachidonate concentrations (approximately 0.15-0.35 mM), a concentration-dependent turn-off of both aggregation and release occurred. At these concentrations the platelets remained functional, and no release of lactate dehydrogenase was observed. A similar biphasic pattern of arachidonate-induced aggregation and release was observed with platelet-rich plasma, over a similar range of arachidonate to albumin mole ratios. These studies demonstrate that PDGF and other alpha-granule constituents can be released from platelets specifically by arachidonate via an indomethacin-sensitive pathway, most probably involving the platelet cyclooxygenase and conversion of arachidonate to prostaglandin metabolities. The mechanisms responsible for the turn-off of the specific arachidonate-mediated responses at higher arachidonate concentrations remain to be defined.