A study of the first eight hours in the stabilization of plasma testosterone concentration in the hemicastrated rat.
Plasma levels of testosterone fell within 4 h after hemicastration in the mature male rat, and recovered within 8 h, without a compensatory rise in plasma LH from 5 to 480 min after surgery. Pulsatile release of LH was not observed in any group, suggesting the possibility that its alteration was not stimulating the single testis. Luteinizing hormone releasing hormone (LH-RH) stimulated plasma LH concentration equally in both control and hemicastrated rats, rising more sharply only in sham-hemicastrated rats treated with a low dose of LH-RH. Plasma LH rose significantly at the same time (6h after surgery) in both castrated (in one step) and hemicastrated rats which were castrated (in two steps). Bilateral denervation of the testis did not affect the response of plasma testosterone after hemicastration. There was a remarkably similar response in both plasma LH and testosterone levels to handling, blood collection, anaesthesia, sham-surgery and hemicastration separately or in combination. It was concluded that the response of testosterone to hemicastration was neither related to early changes in plasma LH levels nor to alterations in the hypothalamo-hypophysial axis.
D000818:Animals; D002369:Castration; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000378:metabolism* / Q000502:physiology; D013739:Testosterone / Q000096:biosynthesis* / Q000097:blood / Q000378:metabolism; D013997:Time Factors
D013739:Testosterone; D007986:Luteinizing Hormone