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Diurnal variation in gonadotropic potency of the adenohypophysis of Japanese quail (Coturnix coturnix japonica)

1966; Elsevier BV; Volume: 6; Issue: 1 Linguagem: Inglês

10.1016/0016-6480(66)90105-5

1095-6840

Katuhide TANAKA, Wilbor O. Wilson, Fred Mather, L.Z. McFarland,

Livestock and Poultry Management

Japanese quail (Coturnix coturnix japonica) were raised from hatch under one of the following light regimens: continuous light, repeated cycles of 16 hours light and 8 hours darkness (16L:8D), 14L:10D, 6L:6D, and 8L:16D. The gonadotropic potencies of the acetone-dried adenohypophysis were determined for groups of 4-week-old males killed after exposure to various periods of light and of dark. The potencies were estimated by bioassay in which the weight increase in the testes of 2-week-old male coturnix that were reared under 8L:16D was used. In quail exposed to continuous light, gonadotropic potency of the adenohypophysis did not differ significantly among birds killed at 8-hour intervals. In birds subjected to 16L:8D, 14L:10D or 6L:6D, the potency was higher at the end of the light period than at 3 or 4 hours after beginning of darkness. No significant difference was observed in potencies during darkness. The results indicate that gonadotropin content in the adenohypophyses from immature male coturnix reared under certain light regimens changes with the daily light-dark rhythms.