Expression of Follistatin and Inhibin/Activin Subunit Genes in Porcine Follicles

Authors

M.D. Li, USDA-ARS
L.V. DePaolo, Whittier Institute for Diabetes and Endocrinology
J.J. Ford, USDA-ARS

Document Type

Article

Date of this Version

1997

Comments

Published in BIOLOGY OF REPRODUCTION 57, 112-118 (1997).

Abstract

Expression of the follistatin (FS) and inhibin/activin (I/A) α, β_A, and β_B subunit genes in porcine ovarian follicles was evaluated by reverse transcriptase polymerase chain reaction and/or RNase protection procedures to establish changes during the final stages of follicular development. For the I/A α and β_A subunits, expression increased (p < 0.05) as follicles progressed to the mid-stage of the follicular phase. The β_B, subunit was expressed in lower concentrations, and all three I/A subunits showed a marked reduction (p < 0.01) in expression by the late stage of follicular development. In contrast to this pattern, FS gene expression decreased (p < 0.05) as follicles developed from the early (low estradiol) to the mid stage (high estradiol) and continued to decline in advanced follicles (after estrus). The predominant mRNA encoded for FS-315, and the ratio of mRNA for FS-315 to mRNA for FS-288 did not differ significantly during the three stages. Within an animal, concentration of FS mRNAs was related more to stage of the follicular phase than to follicular size. Follicular fluid concentration of FS changed in a manner similar to that observed for expression of its gene. We conclude that expression of the FS gene and translation of its mRNA decrease as follicles approach ovulatory status.