Developmental changes of serum thymosin alpha 1 and beta 4 in male and male castrated pigs: modulation by testosterone and human chorionic gonadotropin.
Thymic secretory peptides thymosin beta 4 and alpha 1 have possible endocrine roles in both immune and reproductive systems; thus, they should respond to endocrine feedback control mechanisms consistent with gonadal function. In an initial experiment, male pigs (boars; n = 90; 10/time) were bled at 1, 3, 6, 12, 18, 24, 30, 36, and 96 wk of age before and 24 h after hCG stimulation. Thymosin beta 4 concentrations were significantly depressed 24 h after hCG challenge. Testosterone concentrations increased with age up to 36 wk and were further increased with hCG stimulation (p less than 0.01). In a subsequent experiment, boars (n = 12) and barrows (males castrated shortly after birth; n = 12) were blood-sampled, administered hCG, and sampled again 24 h later at 1, 3, 6, 12, 18, and 24 wk of age. Barrows (n = 12) were administered testosterone with the same protocol. Testosterone concentrations increased in boars with maturity and were further increased from the hCG stimulation (p less than 0.01). Thymosin beta 4 concentrations decreased with age in boars and barrows (p less than 0.01), and hCG challenge depressed thymosin alpha 1 and beta 4 concentrations in boars and thymosin beta 4 in barrows (p less than 0.01). Testosterone treatment of barrows also depressed thymosin beta 4 and alpha 1 in barrows (p less than 0.01). The depression of thymosins by hCG treatment points to a role for gonadotropins in altering circulating thymosin concentrations independent of, but in conjunction with, the effect of gonadal steroids.
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USDA, ARS, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166.
D000818:Animals; D002369:Castration; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003864:Depression, Chemical; D006801:Humans; D008297:Male; D013552:Swine; D013737:Testis / Q000187:drug effects / Q000502:physiology; D013739:Testosterone / Q000097:blood / Q000494:pharmacology*; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000097:blood; D000099201:Thymosin beta(4)
D006063:Chorionic Gonadotropin; D013739:Testosterone; D000077596:Thymalfasin; D013947:Thymosin; D000099201:Thymosin beta(4)