Developmental Programming: Effect of Prenatal Steroid Excess on Intraovarian Components of Insulin Signaling Pathway and Related Proteins in Sheep1

Abstract

Prenatal testosterone (T) excess increases ovarian follicular recruitment, follicular persistence, insulin resistance, and compensatory hyperinsulinemia. Considering the importance of insulin in ovarian physiology, in this study, using prenatal T- and dihydrotestosterone (DHT, a nonaromatizable androgen)-treated female sheep, we tested the hypothesis that prenatal androgen excess alters the intraovarian insulin signaling cascade and metabolic mediators that have an impact on insulin signaling. Changes in ovarian insulin receptor (INSRB), insulin receptor substrate 1 (IRS1), mammalian target of rapamycin (MTOR), phosphatidylinositol 3-kinase (PIK3), peroxisome proliferator-activated receptor-gamma (PPARG), and adiponectin proteins were determined at fetal (Days 90 and 140), postpubertal (10 mo), and adult (21 mo) ages by immunohistochemistry. Results indicated that these proteins were expressed in granulosa, theca, and stromal compartments, with INSRB, IRS1, PPARG, and adiponectin increasing in parallel with advanced follicular differentiation. Importantly, prenatal T excess induced age-specific changes in PPARG and adiponectin expression, with increased PPARG expression evident during fetal life and decreased antral follicular adiponectin expression during adult life. Comparison of developmental changes in prenatal T and DHT-treated females found that the effects on PPARG were programmed by androgenic actions of T, whereas the effects on adiponectin were likely by its estrogenic action. These results suggest a role for PPARG in the programming of ovarian disruptions by prenatal T excess, including a decrease in antral follicular adiponectin expression and a contributory role for adiponectin in follicular persistence and ovulatory failure.

Developmental Programming: Impact of Prenatal Testosterone Excess on Insulin Sensitivity, Adiposity, and Free Fatty Acid Profile in Postpubertal Female Sheep

“…Developmental changes in insulin sensitivity across the life span discussed above (Figure 4) emphasize the need for considering homogeneity of the study population and importantly the age of testing in addressing the controversy in this field. Furthermore, the positive correlation found between serum and follicular fluid FFAs, specifically palmitic and stearic, and the reduced in vitro fertilization outcomes with increased FFAs in women with PCOS (72), suggest that the disruption in ovarian (73,74) and reproductive function (75) evidenced in prenatal T-treated females, may be mediated in part via disruption in FFA metabolism evidenced in this study.…”

Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions

“…However, gestational T increases AR in these follicles supporting functional hyperandrogenism [39]. The reduced adiponectin in granulosa cells of prenatal T sheep may affect follicular insulin sensitivity and compromise growth [99]. Findings that prenatal T-treatment reduces anti-apoptotic protein BCL2 and the apoptosis effector protein caspase-3 in granulosa cells of antral follicles [81] support a shift in the balance of the pro- versus anti-apoptotic genes that likely arrest the follicle from undergoing atresia or developing further.…”

Altered Expression of Pro-inflammatory Cytokines in Ovarian Follicles of Cows with Cystic Ovarian Disease

“…the brown label). The positive controls were used as interassay controls to maximize the levels of accuracy and robustness of the method (Ranefall et al, 1998;Ortega et al, 2010). The methodological details of image analysis as a valid method to quantify protein expression have been described previously Ortega et al, 2010).…”