Influence of a gonadotropin-releasing hormone agonist on circulating concentrations of luteinizing hormone and testosterone and tissue concentrations of compounds associated with boar taint.
Twenty-four Yorkshire boars and six barrows approximately 8 mo of age were used to evaluate the effects of a GnRH agonist (GnRH-A) on circulating concentrations of LH and testosterone (T), concentrations of skatole in fat, and concentrations of 16-androstene steroids in fat and salivary glands. Pigs were assigned to five groups of six pigs each: L200, boars injected with 200 micrograms of GnRH-A/kg BW; L50, boars injected with 50 micrograms of GnRH-A/kg BW; Boar, boars treated with vehicle; Castrate, males castrated on the same day that Groups 1 to 3 received injections; and Barrow, males castrated as neonates. Pigs in L200, L50, and Boar were only given one injection. Blood samples were taken twice daily from d -2 to 28 for determinations of T and LH concentrations and at 15-min intervals for 6 h on d -1, 1, 7, 14, 21, and 28 for characterization of pulsatile LH release. Pigs were slaughtered on d 30, and samples of backfat and salivary glands were collected for quantification of skatole and 16-androstene steroid concentrations. The LH concentrations increased immediately following GnRH-A injection in L200 and L50 (P < .001) and then declined to pretreatment values by approximately 29 h after treatment. Serum T concentrations in L200 and L50 increased after GnRH-A treatment (P < .0001) and then decreased to less than pretreatment concentrations by d 5 in L200 (P < .001) and by d 8 in L50 (P < .01). Concentrations of 16-androstene steroids in fat were less (P < .05) in L200 and Barrow than in Boar.(ABSTRACT TRUNCATED AT 250 WORDS)
Xue
J L
JL
Department of Clinical and Population Sciences, University of Minnesota, St. Paul 55108.
Dial
G D
GD
Bartsh
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Kerkaert
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Squires
E J
EJ
Marsh
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Ferre
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D000273:Adipose Tissue / Q000737:chemistry*; D000736:Androstenes / Q000032:analysis; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D009929:Organ Size / Q000187:drug effects; D012469:Salivary Glands / Q000737:chemistry; D012862:Skatole / Q000032:analysis; D013552:Swine / Q000097:blood / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000254:growth & development; D013739:Testosterone / Q000097:blood*
D000736:Androstenes; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D012862:Skatole