Skip to main content
ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #370522
Research Project: Improving Livestock Production by Developing Reproductive and Precision Management Technologies

Location: Livestock Bio-Systems

Title: Relationship among GnRH-R mRNA abundance and GnRH-I, GnRH-II, and intrafollicular steroid hormone concentrations in granulosa cells of bovine antral follicles at specific stages of follicular development

Author
item RICH, JERICA - South Dakota State University
item NORTHROP, EMMALEE - South Dakota State University
item EPPERSON, KAITLIN - South Dakota State University
item MENEGATTI ZOCA, SAULO - South Dakota State University
item PERKINS, STEPHANIE - South Dakota State University
item DALY, RUSSELL - South Dakota State University
item Cushman, Robert - Bob
item PERRY, GEORGE - South Dakota State University

Submitted to: International Congress on Animal Reproduction
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Transcript abundance of two forms of GnRH and the peptide receptor (GnRH-R) have been characterized in bovine ovaries in separate studies. Further, an inverse relationship was reported for granulosa cell (GC) GnRH-1 and GnRH-2 mRNA abundance and intrafollicular estradiol-17ß (E2). The objective of this study was to investigate the relationship of GnRH-1, GnRH-2, GnRH-R, and intrafollicular 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 present per stage was aspirated to obtain 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 P4 across follicular stages. There was an effect of stage on FF E2 (17,925±20,273, 28,458±21,503, and 252,616±21,503 pg/mL for PRE, POST, and PG, respectively; P<0.01). There was an effect of stage on GnRH-1 mRNA abundance (2.28±0.55, 0.92±0.55, and 0.11±0.55 for PRE, POST, and PG, respectively; P=0.03). There was no relationship of GnRH-1 and GnRH-2 mRNA abundance or FF P4 on GnRH-R mRNA abundance (P=0.23). As FF E2 increased there was a tendency for GnRH-R mRNA abundance to increase (P=0.10; r2=0.13). In agreement with previous reports, as FF E2 increased GnRH-1 mRNA abundance decreased (P=0.02; r2=0.20). There was no effect of FF P4 on GnRH-1 mRNA abundance (P=0.68). There was no effect (P=0.66) of FF E2 on GnRH-2 mRNA abundance. As FF P4 concentrations increased there was a tendency for GnRH-2 mRNA abundance to decrease (P=0.09; r2=0.12). 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 the potential regulatory relationship between ovarian GnRH and steroidogenesis. This work is supported by AFRI Grant No. 2018-67016-27578 from USDA.