U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version



Published in J. Anim. Sci. (1990) 68: 1044-1048


Relationships of implanted testosterone, dihydrotestosterone and estradiol-17β to collagen degradation and intramuscular collagen concentration and stability were determined. Intramuscular collagen content, solubility and shrinkage temperature and serum hydroxyproline were analyzed in groups of six rams, wethers, and wethers implanted with various levels of testosterone or dihydrotestosterone (Exp. 1) and groups of 10 rams, wethers and wethers implanted with estradiol-17β, dihydrotestosterone or a combination of these two steroids (Exp. 2). Intramuscular collagen content in both experiments was higher (P < .05) in muscles of rams than in muscles of wethers. Administration of the highest level of testosterone to wethers raised (P < .05) total and insoluble intramuscular collagen to concentrations noted in rams. Administration of the testosterone metabolite, dihydrotestosterone, to wethers had no effect on intramuscular collagen. Administration of estradiol-17β to wethers tended to raise concentrations of intramuscular collagen so that they were no longer lower (P < .05) than those in rams. Collagen stability as measured by solubility and thermal shrinkage temperature did not differ among rams, wethers or implanted wethers (P > .05). Increases in collagen accretion due to hormone administration were observed to be the result of increases in the insoluble portion of the intramuscular collagen (P < .05).