Studies of pituitary-adrenal-testis interaction in sheep. III. The effects of repeated injections of adrenocorticotrophic hormone in recently castrated rams.
Twice daily for 5.5 d, 0.5 ug of long-acting adrenocorticotrophic hormone (ACTH, Synacthen-Depot) was administered to four rams castrated 17 d earlier. There was a progressive diminution in basal plasma follicle stimulating hormone (FSH) during and after treatment. ACTH also suppressed basal plasma luteinizing hormone (LH) concentrations and the maximum LH values reached and the quantity of LH released in response to the injection of 5 ug of gonadotrophin releasing hormone (GnRH). There was, however, evidence that the LH concentrations returned to pretreatment levels after ACTH treatment ceased. This experiment demonstrated that the effects of ACTH on LH are modulated by castration, but throughout this series of experiments ACTH always depressed LH activity. In contrast, FSH is affected by ACTH in different ways, depending on the season and the presence or absence of a testis.
Cox
J E
JE
Division of Equine Studies with Farm Animal Surgery Department of Veterinary Clinical Science University of Liverpool Veterinary Field Station Leahurst, Neston, South Wirral, L64 7TE, U.K.
Mohamed
F H
FH