PhD Oral Exam - Lauren Buynack, Psychology

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Progestogens are important for cognition and are implicated in neuropsychiatric disorders. Sex differences may be explained, in part, by sex hormones. Most of the research on progesterone receptors has focused on nuclear progesterone receptors. Membrane progesterone receptors (mPRs) are located on the cell membrane and their effects in the brain are virtually unknown. Two mPRs have been identified in the nervous system; mPRβ and mPRδ. In these studies, 18 ovariectomized Long Evans female rats received one of three hormone treatments; low E2 (17β-estradiol; 5% E2 in cholesterol capsule), high E2 (10 μg/kg; 5% E2 capsule), and high E2 (10 μg/kg; 5% E2 capsule) plus progesterone (500 μg/kg). Anti-mPRβ and anti-mPRδ immunoreactivity were analyzed in the hippocampus (chapter 1), striatum (chapter 2), and medial prefrontal cortex (chapter 3). Results show that the mPR density did not differ by hormonal condition for any brain region. Though they are richly found throughout the hippocampus, striatum, and medial prefrontal cortex. The lack of differences between hormone conditions in mPR levels suggests that sex difference occur as a function of the amount of hormone activating them. The activation of mPRs may explain the sex differences observed in cognition and neurodegenerative disorders.