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. (8th October 2021)

• Record Type: Journal Article
• Authors: Rich, Jerica J; Northrop-Albrecht, Emmalee J; Epperson, Kaitlin M; Zoca, Saulo Menegatti; Perkins, Stephanie D; Daly, Russell F; Cushman, Robert A; Perry, George A
• Is Part Of: Journal of animal science. Volume 99(2021)Supplement 3
• Page Start: 126
• Page End: 127
• Publication Date: 2021-10-08
• Subjects: GnRH -- Ovary -- follicular fluid; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/skab235.230
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: 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;r 2 =0.13). As FF P4 concentrations increased GnRH-2 mRNA abundance tended to decrease (P = 0.09;r 2 =0.12). As FF E2 increased GnRH-1 mRNA abundance decreased (P = 0.02;r 2 =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.