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Title: PITUITARY RELATIONSHIP OF GONADOTROPINS AND MESSENGER RIBONUCLEIC ACID FOR GONADOTROPIN SUBUNITS IN WHITE COMPOSITE AND MEISHAN BOARS

Author
item ZANELLA, ERALDO - UNIVERSITY OF NEBRASKA
item Ford, Johny
item Wise, Thomas
item HAMERNIK, DEBORA - UNIVERSITY OF NEBRASKA

Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Follicle stimulating hormone (FSH) is required for growth and development of ovarian follicles, and secretion of FSH is greater in Meishan boars than in boars of other breeds of swine. We are interested in regulation of reproduction in Meishan swine because ovulation rate is greater in this breed than in other breeds available to U.S. swine producers. We determined that messenger RNA for the two proteins that combine to form FS was greater in the anterior pituitary glands of Meishan boars than in white crossbred boars. These observations will assist in the design of subsequent studies relating to improvement of litter size in swine.

Technical Abstract: Two experiments were conducted to compare amounts of mRNAs for gonadotropin subunits in two breeds of pigs that are genetically distinct for litter size: the Chinese Meishan and white composite (a composite of four European White breeds: Yorkshire, Landrace, Large White, and Chester White). In experiment 1, pituitaries were collected from mature Meishan and white composite boars. In experiment 2, boars were assigned to three groups according to peripheral concentrations of follicle stimulating hormone (FSH): white composite (~100 ng/ml), Meishan with low FSH (< 500 ng/ml) and Meishan with high FSH (> 750 ng/ml). In experiment 1, pituitary weight, content and concentration of FSH were greater (p<.05) in Meishan than white composite boars. Sizes of gonadotropin subunit mRNA were similar in pigs and cattle. Amounts of mRNA for alpha subunit and LH-beta subunit were not different (p=.14 and .08, respectively) between breeds. Meishan boars, however, had greater (p<.01) amounts of mRNA for FSH-beta subunit compared to white composite boars. In experiment 2, Meishan males with high FSH had greater (p<.05) amounts of mRNA for all three gonadotropin subunits compared to white composite males. From these results we suggest that greater levels of gonadotropins in circulation of Meishan boars result, in part, from increased amounts of mRNA for gonadotropin subunits when compared with white composite breed of boars.