Experimentally Induced Hyperinsulinemia Fails to Induce Polycystic Ovary Syndrome-like Traits in Female Rhesus Macaques.

As in women with polycystic ovary syndrome (PCOS), hyperinsulinemia is associated with anovulation in PCOS-like female rhesus monkeys. Insulin sensitizers ameliorate hyperinsulinemia and stimulate ovulatory menstrual cycles in PCOS-like monkeys. To determine whether hyperinsulinemia (>694 pmol/L), alone, induces PCOS-like traits, five PCOS-like female rhesus monkeys with minimal PCOS-like traits, and four control females of similar mid-to-late reproductive years and body mass index, received daily subcutaneous injections of recombinant human insulin or diluent for 6−7 months. A cross-over experimental design enabled use of the same monkeys in each treatment phase. Insulin treatment unexpectedly normalized follicular phase duration in PCOS-like, but not control, females. In response to an intramuscular injection of 200 IU hCG, neither prenatally androgenized nor control females demonstrated ovarian hyperandrogenic responses while receiving insulin. An intravenous GnRH (100 ng/kg) injection also did not reveal evidence of hypergonadotropism. Taken together, these results suggest that experimentally induced adult hyperinsulinemia, alone, is insufficient to induce PCOS-like traits in female rhesus monkeys and to amplify intrinsic PCOS-like pathophysiology.

Fetal programming of adrenal androgen excess: lessons from a nonhuman primate model of polycystic ovary syndrome.

Adrenal androgen excess is found in adult female rhesus monkeys previously exposed to androgen treatment during early gestation. In adulthood, such prenatally androgenized female monkeys exhibit elevated basal circulating levels of dehydroepiandrosterone sulfate (DHEAS), typical of polycystic ovary syndrome (PCOS) women with adrenal androgen excess. Further androgen and glucocorticoid abnormalities in PA female monkeys are revealed by acute ACTH stimulation: DHEA, androstenedione and corticosterone responses are all elevated compared to responses in controls. Pioglitazone treatment, however, diminishes circulating DHEAS responses to ACTH in both prenatally androgenized and control female monkeys, while increasing the 17-hydroxyprogesterone response and reducing the DHEA to 17-hydroxyprogesterone ratio. Since 60-min post-ACTH serum values for 17-hydroxyprogesterone correlate negatively with basal serum insulin levels (all female monkeys on pioglitazone and placebo treatment combined), while similar DHEAS values correlate positively with basal serum insulin levels, circulating insulin levels may preferentially support adrenal androgen biosynthesis in both prenatally androgenized and control female rhesus monkeys. Overall, our findings suggest that differentiation of the monkey adrenal cortex in a hyperandrogenic fetal environment may permanently upregulate adult adrenal androgen biosynthesis through specific elevation of 17,20-lyase activity in the zona fasciculata-reticularis. As adult prenatally androgenized female rhesus monkeys closely emulate PCOS-like symptoms, excess fetal androgen programming may contribute to adult adrenal androgen excess in women with PCOS.

Pioglitazone improves insulin action and normalizes menstrual cycles in a majority of prenatally androgenized female rhesus monkeys.

PURPOSE OF THE STUDY: To determine whether pioglitazone will improve menstrual cyclicity in a fetal programming model for polycystic ovary syndrome. BASIC PROCEDURES: Eight prenatally androgenized (PA) and 5 control female rhesus monkeys of similar age, body weight and body mass index received an oral placebo daily for 6-7 months followed, after at least 90 days, by daily oral dosing with pioglitazone (3mg/kg) for an additional 6-7 months. Blood was sampled thrice weekly to monitor ovulatory function, and a variety of endocrine challenges were performed to quantify changes in ovarian, gonadotropin and glucoregulatory function. MOST IMPORTANT FINDINGS: Pioglitazone normalized menstrual cycles in 5 out of 8 (62%) PA females (pioglitazone responsive; Pio(RESP)). Pioglitazone increased serum 17alpha-hydroxyprogesterone responses to an hCG injection in Pio(RESP) PA females, while diminishing serum progesterone, and increasing DHEA and estradiol responses to hCG in Pio(RESP) PA and all normal females. PRINCIPAL CONCLUSIONS: Insulin resistance plays a mechanistic role in maintaining anovulation in a majority of PA female monkeys.

Adrenal hyperandrogenism is induced by fetal androgen excess in a rhesus monkey model of polycystic ovary syndrome.

CONTEXT: Adrenal androgen excess is found in approximately 25-60% of women with polycystic ovary syndrome (PCOS), but the mechanisms underlying PCOS-related adrenal androgen excess are unclear. OBJECTIVE: The objective of this study was to determine whether adrenal androgen excess is manifest in a nonhuman primate model for PCOS. PARTICIPANTS: Six prenatally androgenized (PA) and six control female rhesus monkeys of similar age, body weight, and body mass index were studied during d 2-6 of two menstrual cycles or anovulatory 30-d periods. INTERVENTIONS: Predexamethasone adrenal steroid levels were assessed in the first cycle (cycle 1). In a subsequent cycle (cycle 2), occurring one to three cycles after cycle 1, adrenal steroids were determined 14.5-16.0 h after an i.m. injection of 0.5 mg/kg dexamethasone (postdexamethasone levels) and after an i.v. injection of 50 microg ACTH-(1-39). RESULTS: Both before and after dexamethasone, serum levels of dehydroepiandrosterone (DHEA) in PA females exceeded those in controls. After ACTH injection, PA females exhibited higher circulating levels of DHEA, androstenedione, and corticosterone but comparable levels of 17alpha-hydroxyprogesterone, cortisol, the sulfoconjugate of DHEA, and testosterone compared with controls. CONCLUSION: Enhanced basal and ACTH-stimulated adrenal androgen levels in PA female monkeys may reflect up-regulation of 17,20 lyase activity in the adrenal zona reticularis, causing adrenal androgen excess comparable with that found in PCOS women with adrenal androgen excess. These findings open the possibility that PCOS adrenal hyperandrogenism may have its origins in fetal androgen excess reprogramming of adrenocortical function.

Reduced intrafollicular androstenedione and estradiol levels in early-treated prenatally androgenized female rhesus monkeys receiving follicle-stimulating hormone therapy for in vitro fertilization.

Five early-treated and four late-treated prenatally androgenized and five normal female rhesus monkeys were studied to determine whether prenatal testosterone propionate exposure beginning Gestational Days 40-44 (early-treated) or 100-115 (late-treated) affects follicular steroidogenesis during recombinant human FSH (rhFSH) treatment. All monkeys underwent rhFSH injections, without human chorionic gonadotropin administration, followed by oocyte retrieval. Serum FSH, LH, estradiol (E2), progesterone (P), 17alpha-hydroxyprogesterone (17 OHP), androstenedione (A4), testosterone, and dihydrotestosterone were measured basally during rhFSH therapy and at oocyte retrieval. Follicle fluid (FF) sex steroids, oocyte fertilization, and embryo development were analyzed. Circulating FSH, E2, 17 OHP, A4, and dihydrotestosterone levels increased similarly in all females. Serum LH levels decreased from basal levels in normal and late-treated prenatally androgenized females but were unchanged in early-treated prenatally androgenized females. Serum P levels at oocyte retrieval were comparable with those before FSH treatment in all females. All prenatally androgenized females showed reduced FF levels of A4 and E2 but not P or dihydrotestosterone. Intrafollicular T concentrations also were significantly lower in late-treated compared with early-treated prenatally androgenized females or normal females. In early-treated prenatally androgenized females, but not the other female groups, intrafollicular A4 and E2 levels were reduced in follicles containing oocytes that failed fertilization or produced zygotes with cleavage arrest before or at the five- to eight-cell embryo stage. Therefore, in monkeys receiving rhFSH therapy alone without human chorionic gonadotropin administration, early prenatal androgenization reduced FF concentrations of E2 and A4 in association with abnormal oocyte development, without having an effect on P, testosterone, or dihydrotestosterone concentrations.

Impaired developmental competence of oocytes in adult prenatally androgenized female rhesus monkeys undergoing gonadotropin stimulation for in vitro fertilization.

To determine whether prenatal T propionate exposure beginning gestational d 40-44 (early-treated) or 100-115 (late-treated) affects oocyte competence, five early-treated and five late-treated prenatally androgenized and five normal monkeys underwent recombinant human FSH injections with oocyte-retrieval after hCG administration. Serum FSH, LH, estradiol (E(2)), progesterone (P(4)), androstenedione (A(4)), T, and dihydrotestosterone were measured basally, during gonadotropin stimulation and at oocyte-retrieval; fasting serum glucose and insulin also were determined basally and at oocyte-retrieval. Follicle fluid sex steroids were analyzed. Oocyte number, nuclear maturity, and fertilization were comparable among female groups, but the percentage of zygotes developing into blastocysts was reduced in early-treated prenatally androgenized females. The intrafollicular P(4)/E(2) ratio was significantly elevated in early-treated prenatally androgenized females, whereas intrafollicular P(4)/A(4) and T/A(4) ratios were significantly increased in all prenatally androgenized females. Early-treated prenatally androgenized females demonstrated persistent LH hypersecretion. They also were unable to suppress circulating insulin levels during gonadotropin stimulation. Circulating sex steroid levels and serum P(4)/E(2), P(4)/A(4), and E(2)/androgen ratios were similar in all females. Early prenatal androgenization in monkeys receiving gonadotropins impairs oocyte developmental competence and seems to induce premature follicle differentiation in the presence of LH hypersecretion and relative insulin excess.