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United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
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Developmental Changes In Spermatogenesis, Testicular Carnitine Acetyltransferase Activity And Serum Testosterone In The Ram, B. D. Schanbacher, W. R. Gomes, N. L. Vandemark
Developmental Changes In Spermatogenesis, Testicular Carnitine Acetyltransferase Activity And Serum Testosterone In The Ram, B. D. Schanbacher, W. R. Gomes, N. L. Vandemark
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Total of 73 crossbred rams was used to determine spermatogenic and steroidogenic changes in the testis of the growing animal. Testicular weight increased slowly until 80 days of age, then increased tenfold during the following 3 months. Spermatogenesis began in rams at 60 to 70 days of age and was qualitatively complete by 120 days. Although testicular levels of the enzyme carnitine acetyltransferase (CAT) increased in growing rams, CAT did not appear to be uniquely associated with any particular cell type. Therefore, this enzyme was judged to be unsatisfactory as a cell "marker" in studying spermatogenesis in this species. Serum …
Diurnal Rhythm In Serum Testosterone Levels And Thymidine Uptake By Testes In The Domestic Fowl, B. D. Schanbacher, W. R. Gomes, N. L. Vandemark
Diurnal Rhythm In Serum Testosterone Levels And Thymidine Uptake By Testes In The Domestic Fowl, B. D. Schanbacher, W. R. Gomes, N. L. Vandemark
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Serum testosterone levels were measured by radioimmunoassay at 3-hr. intervals in a total of 80 mature Dwarf Leghorn cocks, and incorporation of thymidine-3H in testes was measured by radioautography in an additional 24 birds. Serum testosterone was higher at night (P< 0.02), averaging 7.14 ± 0.55 ng/ml during light hours (0900-1800 hr.), and 9.42 ± 0.73 ng/ml (P < 0.02) during darkness (2100-0600 hr.). In a second experiment to determine the rate of incorporation of thymidine into testes, birds were inadvertently subject to continuous artificial light during the 24-hr. study period; uptake of thyrnidine-3H did not differ between day and nighttime periods, averaging 174 ± 5 and 177 ± 4 tritium-labeled cells per mm2, respectively. These data suggest that, during the Ohio spring season, testosterone production is favored at night. Spermatogenic DNA production may not vary diurnally, but the unusual lighting scheme involved may have altered the …