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ARS Home » Research » Publications at this Location » Publication #65955
Title: EXPRESSION OF FOLLISTATIN AND INHIBIN/ACTIVIN SUBUNIT GENES IN PORCINE FOLLICLES

Author
item Li, Ming
item DEPAOLO, L - WHITTIER INSTITUTE, CA
item Ford, Johny

Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Differences in ovulation rate result from differences in the number of follicles that are selected to participate in the final stages of follicular development. Thus, an increase in follicular selection would increase litter size. We investigated expression of the follistatin gene in porcine ovarian follicles and observed that expression of this gene decreased as females approached the time of ovulation. Within a female, concentration of follistatin mRNA was similar in antral follicles of all sizes; thus, we conclude that expression of this gene is not associated with selection for ovulation. These results are required for design of subsequent studies.

Technical Abstract: Expression of follistatin (FS), an activin-binding protein, was evaluated during the follicular phase of the porcine estrous cycle by Northern, RT-PC gene expression decreased (P < 0.05) as follicles developed from an early stage (low estradiol) to mid-stage (high estradiol), and continued to decline in advanced follicles (24 h after onset of estrus). The predominant mRNA encoded for the FS-315, and the ratio of mRNA for FS-315 and FS-288 remained constant at 2.5 throughout antral follicular development. Within an animal, concentration of mRNA was related more to stage of the follicular phase than to follicle size. Immunoreactive follistatin decreased (P < 0.01) in follicular fluid with advancing stages of the follicular phase. Follistatin gene expression and translation decreased as follicles approached ovulatory status. Potentially, this change may allow greater access of activin to highly differentiated granulosa cells resulting in decreased steroidogenesis after the ovulatory release of LH.