Developmental Programming: Prenatal and Postnatal Androgen Antagonist and Insulin Sensitizer Interventions Prevent Advancement of Puberty and Improve LH Surge Dynamics in Prenatal Testosterone-Treated Sheep

Abstract

Prenatal T excess induces maternal hyperinsulinemia, early puberty, and reproductive/metabolic defects in the female similar to those seen in women with polycystic ovary syndrome. This study addressed the organizational/activational role of androgens and insulin in programming pubertal advancement and periovulatory LH surge defects. Treatment groups included the following: 1) control; 2) prenatal T; 3) prenatal T plus prenatal androgen antagonist, flutamide; 4) prenatal T plus prenatal insulin sensitizer, rosiglitazone; 5) prenatal T and postnatal flutamide; 6) prenatal T and postnatal rosiglitazone; and 7) prenatal T and postnatal metformin. Prenatal treatments spanned 30-90 days of gestation and postnatal treatments began at approximately 8 weeks of age and continued throughout. Blood samples were taken twice weekly, beginning at approximately 12 weeks of age to time puberty. Two-hour samples after the synchronization with prostaglandin F2α were taken for 120 hours to characterize LH surge dynamics at 7 and 19 months of age. Prenatal T females entered puberty earlier than controls, and all interventions prevented this advancement. Prenatal T reduced the percentage of animals having LH surge, and females that presented LH surge exhibited delayed timing and dampened amplitude of the LH surge. Prenatal androgen antagonist, but not other interventions, restored LH surges without normalizing the timing of the surge. Normalization of pubertal timing with prenatal/postnatal androgen antagonist and insulin sensitizer interventions suggests that pubertal advancement is programmed by androgenic actions of T involving insulin as a mediary. Restoration of LH surges by cotreatment with androgen antagonist supports androgenic programming at the organizational level.

Developmental programming: postnatal estradiol modulation of prenatally organized reproductive neuroendocrine function in sheep

“…Comparison of the effects of prenatal T plus postnatal E-treatment with prenatal T-treatment alone found postnatal E-treatment does not amplify the effects of prenatal T-treatment in reducing responsiveness to E negative feedback and advancing puberty, a finding consistent with our previous studies (Sarma et al 2005, Veiga-Lopez et al 2009, Padmanabhan et al 2015). Instead, postnatal E-treatment delayed puberty relative to controls, while failing to reduce gonadotropin levels in response to the E negative feedback challenge.…”

“…One possibility for this discrepancy is that not sufficient fetal E concentrations were achieved. Alternatively, these findings, in concert with previous findings of partial restoration of preovulatory LH surges in animals co-treated with T and androgen antagonist (Padmanabhan et al 2015), raise the possibility that both androgens and estrogens synergize in programming the prenatal T-induced disruptions in E feedback and periovulatory hormonal dynamics.…”

“…The number of pulses was assessed over a 6h period. For both E-positive feedback and periovulatory hormonal characterization, the LH and FSH surges were defined based on the circulating gonadotropin concentrations being above the baseline plus two times the assay sensitivity and remaining high for at least 8h (Padmanabhan et al 2015). For synchronization of the estrous cycle following PGF 2α injection, daily P concentrations had to fall below 0.5ng/ml.…”

“…In view of the large number of comparisons that reduces power, the magnitude of treatment effects on age at puberty was also examined by effect size analysis (Cohen 1992, Nakagawa & Cuthill 2007, Padmanabhan et al 2015). This analysis allows comparison of the means between two treatments with respect to the magnitude of difference between them.…”

Effect of maternal PCOS and PCOS-like phenotype on the offspring's health

“…Furthermore, postnatal treatment with flutamide, an androgen antagonist, increased the total LH secreted in response to the estradiol positive feedback challenge in prenatal testosterone treated sheep, indicating that postnatal androgens play a role in determining the magnitude of the LH surge (Abi Salloum et al, 2012). Postnatal treatment with flutamide also prevented the advancement of puberty seen in prenatal testosterone treated sheep, suggesting that activation of the androgenic pathway during postnatal development is required for unmasking/amplifying potential alterations programmed by prenatal exposure to excess testosterone (Padmanabhan et al, 2015). While women with PCOS have been reported to present normal preovulatory LH surge in response to estradiol administration (Baird et al, 1977), the inhibitory effects of estradiol and progesterone on LH pulsatile secretion appear to be compromised in these individuals (Eagleson et al, 2000).…”