# REGULATION OF OVARIAN FOLLICULAR STEROID PRODUCTION

> **NIH NIH R01** · CORNELL UNIVERSITY · 1994 · $167,318

## Abstract

During the follicular phase the capacity of preovulatory follicles to
produce androgens and estradiol increases greatly, whereas progesterone
secretion remains low.  In vivo the LH/FSH surge triggers several
dramatic and important changes, including the follicular/luteal phase
shift in steroidogenesis.  During this transition, follicular production
of estradiol and androgen decrease greatly and theca and granulosa cells
shift to primarily progesterone production - i.e., the transformation of
follicle cells to luteal cells is initiated.  Despite the critical
importance of this phase of follicular development to successful
reproduction, little is known about the mechanisms by which the
follicular/luteal phase shift is accomplished, perhaps because the
changes are so rapid.  Oxytocin (OT) is produced by granulosa cells from
humans and a number of other mammalian species, including cattle.
Experiments conducted during the current grant period suggest that in
cattle OT is involved in the mechanism by which the LH surge induces the
initial stages of luteinization.  Cattle offer unique  advantages as a
model for studying regulation of the follicular/luteal phase shift in
mammals because: they can be induced experimentally to initiate luteal
regression and a new follicular phase; large numbers of granulosa and
theca cells can be obtained from a single follicle; and behavioral
estrus serves as marker for the time of the LH/FSH surge.  Therefore
cattle will be used to determine mechanisms of the follicular/luteal
phase shift, to gain insight into this important developmental
transition and to explore the role of a proposed novel regulator, OT.

Aim 1 is to determine the relationship between gonadotropins and OT in
increasing progesterone secretion by bovine granulosa cells, to test the
hypothesis that at least part of the mechanism by which the
gonadotropins "luteinize" granulosa cells is via an increase in OT
production.  Aim 2 is to determine how luteinization is accomplished in
vivo and in vitro in terms of expression of the genes for OT and
specific steroidogenic enzymes.  Experiments in Aim 3 will be focused on
spontaneous luteinization iv vitro to examine mechanisms by which
gonadotropins and OT "luteinize" cells in vitro. In Aim 4 the role of
estradiol as a regulator of luteinization will be evaluated.  The
exciting new technique of follicular microdialysis will be used in Aim
5 to test hypotheses about the roles of LH and OT in the
follicular/luteal phase shift in vivo.

Together these experiments will provide new insight into the regulation
of this transitional stage in follicular development that is so critical
for fertility.

## Key facts

- **NIH application ID:** 2197118
- **Project number:** 5R01HD014584-14
- **Recipient organization:** CORNELL UNIVERSITY
- **SAM.gov UEI:** G56PUALJ3KT5
- **Principal Investigator:** JOANNE E. FORTUNE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $167,318
- **Award type:** 5
- **Project period:** 1980-09-01 → 1996-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197118

## Citation

> US National Institutes of Health, RePORTER application 2197118, REGULATION OF OVARIAN FOLLICULAR STEROID PRODUCTION (5R01HD014584-14). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197118. Licensed CC0.

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