Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/1998
Publication Date: N/A
Citation: Interpretive Summary: Follicle stimulating hormone (FSH) plays a primary role in regulation of sperm production. The objective of the current research was to define in greater detail factors that control FSH secretion in boars. Anterior pituitary glands were obtained from two groups of mature boars that differed in their blood concentrations of FSH. Gene expression for FSH-beta asubunit, activin beta-B subunit, calmodulin, follistatin and receptors for gonadotropin releasing hormone was quantified. From these evaluations we determined that gene expression of both FSH-beta subunit and activin beta-B subunit was significantly greater in boars with high blood concentrations of FSH, and gene expression of these two subunits was positively correlated with pituitary concentration of FSH. No differences in expression of the three other genes were related to blood FSH concentrations. We conclude that activin beta-B produced from the anterior rpituitary gland is at least partially responsible for the differences in F secretion that existed between these two groups of boars. These observations are important in the design of subsequent studies as scientists seek better technology to maximize sperm production of boars.
Technical Abstract: This study tested our previous hypothesis, developed from comparison of Meishan (MS) to White Composite (WC) boars, that inhibin/activin (I/A) betaB-subunit gene expression in the anterior pituitary gland relates positively to plasma FSH concentrations. Mature crossbred boars (n = 12) were selected for divergence in plasma FSH concentrations, and their anterior pituitary glands were evaluated for expression of the follicle-stimulating hormone-beta (FSH-beta), inhibin/activin betaB (I/A betaB), follistatin (FS), calmodulin and gonadotropin-releasing hormone receptor (GnRH-R) genes by semi-quantitative RT-PCR and/or RNase protection assays (RPA). Expression of the I/A B-subunit gene was positively correlated to that of the FSH-beta gene (RT-PCR: r = 0.96; P < 0.01; RPA: r = 0.68; P < 0.05). In contrast, expression of the FS, GnRH-R and calmodulin genes was not correlated significantly (P > 0.10) with that of the FSH- gene (FS: r = 0.43; GnRH-R: r = 0.46; calmodulin: r = 0.19). Additionally, expression of the FSH-beta gene was correlated positively with pituitary and plasma FSH concentrations (r = 0.69 and 0.88, respectively; P < 0.05). These results support the hypothesis that activin B is partially responsible for elevated FSH concentrations in boars; plus the expression difference of the calmodulin gene previously observed between MS and WC boars represents a breed difference unrelated to FSH.