Session: Physiology and Endocrinology II

243 - Relationship Among Granulosa Cell Gnrh-i, -II, and Receptor Mrna Abundance and Follicular Fluid Steroid Hormone Concentrations of Bovine Antral Follicles at Specific Stages of Follicular Development

Friday, July 16, 2021

3:00 PM – 3:15 PM EST

Location: Kentucky International Convention Center (KICC), M109 & 110

Presenting Author(s)

Jerica J J Rich, Ph.D.

Assistant Professor of Animal Science
Arkansas State University - College of Agriculture
Jonesboro, Arkansas

PDF Slides and Audio

Author(s)

EN

Emmalee J. Northrop-Albrecht, Ph.D.

Research Technician
Mayo Clinic
Minneapolis, Minnesota
Kaitlin M. Epperson, MS

Graduate Student
Texas A&M University
College Station, Texas
Saulo Menegatti Zoca, PhD Candidate

Graduate Student
South Dakota State University
Brookings, South Dakota
SP

Stephanie D. Perkins

Research Technician
South Dakota State University
Brookings, South Dakota
RD

Russell F. Daly

Professor
South Dakota State University
Brookings, South Dakota
RC

Robert A. Cushman, n/a

Research Physiologist
USDA, ARS, U.S. Meat Animal Research Center
Clay Center, Nebraska
GP

George A. Perry

Texas A&M AgriLife Research, Overton
Overton, Texas

Transcript abundance of two forms of GnRH and its receptor have been characterized in bovine ovaries. The objective was to investigate the relationship of GnRH-1, GnRH-2, GnRH-R, intrafollicular estradiol (E2) and progesterone (P4) during follicular development. Ovaries were collected from beef cows at specific stages of follicular development [pre-selection (PRE, n = 9), post-selection (POST, n = 9), and post-selection 24h after luteal regression (PG, n = 9)]. The largest follicle per stage was aspirated to obtain granulosa cells (GC) and follicular fluid (FF). Total cellular RNA was extracted from GC and RT-PCR was performed for GnRH-1, GnRH-2, GnRH-R and GAPDH. Radioimmunoassays were performed to determine FF concentrations of E2 and P4. Data were analyzed using the MIXED and REG procedures in SAS. There was no difference (P ≥ 0.23) in mRNA abundance of GnRH-2, GnRH-R or FF concentrations of P4 across follicular stages. There was an effect of stage on FF E2 (PRE: 17,925±20,273, POST: 28,458±21,503, and PG: 252,616±21,503 pg/mL; P < 0.01). Stage affected GnRH-1 mRNA abundance (PRE: 2.28±0.55, POST: 0.92±0.55, and PG: 0.11±0.55; P = 0.03). There was no relationship of GnRH-1 and GnRH-2 mRNA abundance or effect of FF P4 on GnRH-R mRNA abundance (P ≥ 0.23). There was no effect of FF P4 on GnRH-1 mRNA abundance (P = 0.68). There was no effect of FF E2 on GnRH-2 mRNA abundance (P = 0.66). As FF E2 increased GnRH-R mRNA abundance tended to increase (P = 0.10;r²=0.13). As FF P4 concentrations increased GnRH-2 mRNA abundance tended to decrease (P = 0.09;r²=0.12). As FF E2 increased GnRH-1 mRNA abundance decreased (P = 0.02;r²=0.20). In conclusion, there were differences in peptide and receptor mRNA abundance of GnRH in relation to FF E2 and P4 at specific stages of follicular development. This is supportive of a regulatory relationship between ovarian GnRH and steroidogenesis. This work is supported by AFRI Grant No.2018-67016-27578 from USDA. USDA is an equal opportunity provider and employer.