INTRAMUSCULAR COLLAGEN AND SERUM HYDROXYPROLINE AS RELATED TO IMPLANTED TESTOSTERONE, DIHYDROTESTOSTERONE AND ESTRADIOL-17β IN GROWING WETHERS

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 \u3c .05) in muscles of rams than in muscles of wethers. Administration of the highest level of testosterone to wethers raised (P \u3c .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 \u3c .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 \u3e .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 \u3c .05)

INTRAMUSCULAR COLLAGEN AND SERUM HYDROXYPROLINE AS RELATED TO IMPLANTED TESTOSTERONE, DIHYDROTESTOSTERONE AND ESTRADIOL-17β IN GROWING WETHERS

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 \u3c .05) in muscles of rams than in muscles of wethers. Administration of the highest level of testosterone to wethers raised (P \u3c .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 \u3c .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 \u3e .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 \u3c .05)

IN VITRO TESTOSTERONE SECRETION BY TESTICULAR TISSUE FROM YOUNG BULLS AND THE EFFECTS OF CHRONIC AND ACUTE EXPOSURE TO ESTRADIOL- 17β

The possibility that estradiol-17/3 may directly influence testicular steroidogenesis in bulls was investigated in vitro. Testicular tissues were incubated for 4 h and regression coefficients (b, ng·ml-1·h-1) based on the increase in testosterone in the medium were used to describe testosterone secretion rates. In the first experiment, testicular tissues from control bulls and bulls chronically implanted with estradiol were incubated in the absence (basal conditions) or presence of 10 mlU/ml human chorionic gonadotropin (hCG). Under basal conditions, testosterone secretion rates were similar for tissues from control (b = 24.1 ± 6.0) and implanted (b = 34.7 ± 6.0) bulls. Testosterone secretion rates were increased approximately fourfold during incubation with hCG; tissues from implanted animals secreted testosterone at a higher rate (

Follicle Stimulating Hormone, Luteinizing Hormone and Testicular Leydig Cell Responses to Estradiol Immunization in Ile-de-France Rams

Active immunization of Ile-de-France rams against estradiol (E2) resulted in the production of E2-neutralizing antibodies and an elevation in the plasma concentrations of FSH, LH, and testosterone. The presence of E2 antibodies did not affect the testosterone metabolic clearance rate, indicating that the immunization-mediated 10-fold increase in plasma testosterone was the result of a 10-fold increase in testicular testosterone production. Testis weights, as well as nuclear and cytoplasmic volumes of individual peritubular and perivascular Leydig cells, were greater in E2-immunized rams than in albuminimmunized controls. Leydig cell numbers were not affected by treatment. The E2 antibodies were capable not only of neutralizing the inhibitory effects of endogenous E2 on gonadotropin levels in intact rams, but were able to block the effects of exogenously administered E2 on their FSH and Lii secretory response to castration. It is concluded that circulating E2 in the ram is involved in pituitary-testicular endocrine homeostasis and that E2 immunoneutralization can be employed to enhance testosterone secretion in this species

LIPOGENESIS IN ADIPOSE TISSUE FROM OVARIECTOMIZED AND INTACT HEIFERS IMMUNIZED AGAINST ESTRADIOL AND(OR) IMPLANTED WITH TRENBOLONE ACETATE

Forty-two heifers were allotted randomly to six treatment groups: 1) intact controls, 2) intact heifers implanted with trenbolone acetate, 3) ovariectomized heifers, 4) ovariectomized heifers implanted with trenbolone acetate, 5) intact heifers immunized against estradiol and 6) intact heifers immunized against estradiol and implanted with trenbolone acetate. Blood titers of estradiol-17β were increased over lO0-fold in heifers immunized against estradiol in Freund\u27s complete adjuvant or saline:squalene/arlacel containing Mycobacterium. Lipogenic enzyme activities and acetate incorporation into fatty acids were increased in subcutaneous adipose tissue obtained at slaughter from heifers receiving immunization or the combination of immunization and trenbolone acetate. The increased lipogenic capacity was not reflected in either cell diameter or cells per gram adipose tissue. Ovariectomy in combination with trenbolone acetate caused the lowest activities for all enzymes measured. This treatments also caused the greatest decrease in cell diameter, which resulted in the largest number of cells per gram of adipose tissue. Trenbotone acetate alone had no detectable effect on lipogenesis in the intact heifer, but the combination of ovariectomy and trenbolone acetate caused substantial decreases in enzyme activities, in most cases a significant decrease as compared with ovariectomized heifers. The data suggest that trenbolone acetate is able to depress lipogenesis only when not competing with the effects of circulating estradiol

LIPOGENESIS IN ADIPOSE TISSUE FROM OVARIECTOMIZED AND INTACT HEIFERS IMMUNIZED AGAINST ESTRADIOL AND(OR) IMPLANTED WITH TRENBOLONE ACETATE

Forty-two heifers were allotted randomly to six treatment groups: 1) intact controls, 2) intact heifers implanted with trenbolone acetate, 3) ovariectomized heifers, 4) ovariectomized heifers implanted with trenbolone acetate, 5) intact heifers immunized against estradiol and 6) intact heifers immunized against estradiol and implanted with trenbolone acetate. Blood titers of estradiol-17β were increased over lO0-fold in heifers immunized against estradiol in Freund\u27s complete adjuvant or saline:squalene/arlacel containing Mycobacterium. Lipogenic enzyme activities and acetate incorporation into fatty acids were increased in subcutaneous adipose tissue obtained at slaughter from heifers receiving immunization or the combination of immunization and trenbolone acetate. The increased lipogenic capacity was not reflected in either cell diameter or cells per gram adipose tissue. Ovariectomy in combination with trenbolone acetate caused the lowest activities for all enzymes measured. This treatments also caused the greatest decrease in cell diameter, which resulted in the largest number of cells per gram of adipose tissue. Trenbotone acetate alone had no detectable effect on lipogenesis in the intact heifer, but the combination of ovariectomy and trenbolone acetate caused substantial decreases in enzyme activities, in most cases a significant decrease as compared with ovariectomized heifers. The data suggest that trenbolone acetate is able to depress lipogenesis only when not competing with the effects of circulating estradiol