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Title: BREED DIFFERENCES IN EXPRESSION OF INHIBIN/ACTIVIN SUBUNITS IN PORCINE ANTERIOR PITUITARY GLANDS: RELATIVE TO EXPRESSION IN OVARIAN FOLLICLES

Author
item Li, Ming
item MACDONALD, GORDON - UMDNJ, PISCATAWAY, NJ
item Ford, Johny

Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/22/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The Chinese pig breeds are well known for their prolificacy and Meishan is one the most highly prolific breeds in the world. Previously, we demonstrated that Chinese Meishan boars have higher plasma FSH concentrations than contemporary White composite boars, but this difference does not occur in females of these breeds. We studied expression differences of known regulatory genes of FSH synthesis and secretion; follistatin, alpha-, betaA- and betaB-subunit genes of inhibin/activin, in anterior pituitary glands of these two breeds using semi-quantitative reverse transcription-polymerase chain reaction technique. It was found that the expression of the betaB-subunit gene is about two-fold higher in pituitaries of Meishan boars than in those of White composites, but not in their female pituitaries. No expression differences were detected for other genes screened in this study except that the expression of the alpha-subunit could not be detected in pituitaries of either breed. Subsequently RNase protection assays confirmed the expression difference of the betaB-subunit gene between boar pituitaries of these two breeds. In contrast to observations in pituitaries, alpha-subunit was highly expressed in follicles. Expression of the betaB-subunit gene decreased in concert with alpha- and betaA-subunit genes as follicles approached ovulation. From these observations, we conclude that the expression of the betaA-subunit gene predominates in porcine ovarian follicles; whereas the expression of the betaB-subunit is more abundant in anterior pituitary glands. We predict that activin, a dimer of betaB subunit and a stimulator of FSH secretion, may partially be responsible for elevated pituitary and plasma FSH concentrations in Meishan boars.