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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #360871
Research Project: Improving Livestock Production by Developing Reproductive and Precision Management Technologies

Location: Livestock Bio-Systems

Title: Differences in relative abundance of GnRH-I and GnRH-II 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: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2019
Publication Date: 6/1/2019
Citation: Rich, J.J., Northrop, E.J., Epperson, K.M., Menegatti Zoca, S., Perkins, S.D., Daly, R.F., Cushman, R.A., Perry, G.A. 2019. Differences in relative abundance of GnRH-I and GnRH-II in granulosa cells of bovine antral follicles at specific stages of follicular development [abstract]. Society for the Study of Reproduction Annual Meeting. Abstract Program, p. 95-96. Available: https://community.ssr.org/news-events/past-meetings/annual-meeting575

Interpretive Summary:

Technical Abstract: A previous study reported that bovine follicles with greater follicular fluid concentrations of estradiol had decreased expression of GnRH-I and GnRH-II in granulosa cells (GC). The objective of this study was to characterize relative abundance of GnRH-I and -II mRNA within GC of follicles at specific stages of development. Beef cows were synchronized, and ovaries were collected at specific stages of follicular development [pre-selection (PRE), post-selection (POST), and post-selection 24 h after luteal regression (POST-PG)]. All surface follicles were classified as small (<5mm), medium (5-8mm), or large (>8mm) and aspirated to collect GC. The large follicles from each animal were kept separate and all other follicles were pooled by size within animal (n=27, 27, and 18 for small, medium, and large). Total cellular RNA was extracted, and RT-PCR was performed for GnRH-I, GnRH-II, and GAPDH. Data were analyzed using the MIXED procedure of SAS. Across all follicles, GnRH-I and GnRH-II were not influenced by stage (P=0.27) but were influenced by size (P<0.01). Small follicles (4.55±0.39 and 3.91±0.44, respectively) had greater expression (P=0.01) compared to medium (0.83±0.39 and 1.41±0.44, respectively) and large (0.52±0.47 and 2.12±0.54, respectively) follicles. There was also a stage by size interaction (P<0.01). POST (P<0.01) and POST-PG (P=0.08) small follicles had or tended to have increased expression compared to PRE small follicles, but PRE medium follicles had increased expression (P<0.03) compared to POST-PG medium follicles. When only the largest follicle for each animal was evaluated, stage of development influenced expression of GnRH-I (P=0.03) but not GnRH-II (P=0.91). For GnRH-I, PRE tended (P=0.09; 2.29±0.55) to have increased expression compared to POST (0.92±0.55) and did have greater expression compared to POST-PG (P=0.01; 0.11±0.55). Thus, GnRH within bovine antral follicles may be a key regulator of the follicle’s ability to produce estradiol.