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Pancreatic and adrenal development and function in an ovine model of polycystic ovary syndrome

Ramaswamy, Seshadri

Authors

Seshadri Ramaswamy



Abstract

Polycystic Ovary Syndrome (PCOS) is a complex disorder encompassing reproductive and metabolic dysfunction. Ovarian hyperandrogenism is an endocrine hallmark of human PCOS. In animal models, PCOS-like abnormalities can be recreated by in utero over-exposure to androgenic steroid hormones.
This thesis investigated pancreatic and adrenal development and function in a unique model of PCOS. Fetal sheep were directly exposed (day 62 and day 82 of gestation) to steroidal excesses - androgen excess (testosterone propionate - TP), estrogen excess (diethylstilbestrol - DES) or glucocorticoid excess (dexamethasone - DEX). At d90 gestation there was elevated expression of genes involved in β-cell development and function: PDX-1 (P<0.001), and INS(P<0.05), INSR(P<0.05) driven by androgenic excess only in the female fetal pancreas. β-cell numbers (P<0.001) and in vitroinsulin secretion (P<0.05) were also elevated in androgen exposed female fetuses. There was a significant increase in insulin secreting β-cell numbers (P<0.001) and in vivo insulin secretion (glucose stimulated) (P<0.01) in adult female offspring, specifically associated with prenatal androgen excess. At d90 gestation, female fetal adrenal gene expression was perturbed by fetal estrogenic exposure. Male fetal adrenal gene expression was altered more dramatically by fetal glucocorticoid exposure. In female adult offspring from androgen exposed pregnancies there was increased adrenal steroidogenic gene expression and in vivotestosterone secretion (P<0.01). This highlights that the adrenal glands may contribute towards excess androgen secretion in PCOS, but such effects might be secondary to other metabolic alterations driven by prenatal androgen exposure, such as excess insulin secretion Thus there may be dialogue between the pancreas and adrenal gland, programmed during early life, with implications for adult health Given both hyperinsulinaemia and hyperandrogenism are common features in PCOS, we suggest that their origins may be at least partially due to altered fetal steroidal environments, specifically excess androgenic stimulation.

Thesis Type Thesis
Deposit Date Apr 11, 2016
Peer Reviewed Not Peer Reviewed
Keywords Polycystic Ovary Syndrome (PCOS); Ovarian hyperandrogenism; reproductive and metabolic dysfunction; steroid hormones;
Public URL http://researchrepository.napier.ac.uk/id/eprint/9826
Contract Date Apr 11, 2016
Award Date 2015-03

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