Diurnal Rhythm of Pituitary Gonadotropic Activity of Male Japanese Quail in Relation to Testicular Growth

HASHIGUCHI Mineo, KOGA Osamu, NISHIYAMA Hisayoshi

doi:10.2508/chikusan.48.9_418

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Other Title

雄ウズラにおける下垂体前葉の性腺刺激ホルモン力価の日内変動と精巣の発達との関連
ユウウズラニオケルカスイタイゼンヨウノセイセンシゲキホルモン

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Description

Male Japanese quail were exposed to 14-hr (5:00-19:00) light: 10-hr darkness (14 L:10 D) from 1 day to 28 days of age and exposed to 8L (5:00-13:00) :16D from 29 days to 49 days of age. Thereafter the birds were again transferred to 14L: 10D for photostimulation. Gonadotropic activities of the anterior lobes of the pituitary were measured at various times during the 24-hr period in relation to testicular growth with a bioassay method based on 32P-uptake by one-dayold chick testes. The mean testicular weights increased from the 2nd to 35th day of exposure to 14L: 10D and an abrupt increase was observed between the 7th and 21st day. Thereafter the weight reached a plateau. Under 8L: 16D and on the 1st day of exposure to 14L: 10D, no diurnal changes in the pituitary gonadotropic activity were observed but on the 2nd day the activity showed a peak at 19:00 (14hr after the onset of light). On the 7th and 21st day, two peaks of the activity were found at 8:00 (3hr after the onset of light) and 22:00 (17hr after the onset of light or 3hr after the onset of darkness). However, only one peak was found at 19:00 (14hr after the onset of light) on the 35th and 49th day. These results indicate that the diurnal rhythm of pituitary gonadotropic activity of male quail appears after transfer of the birds from short days to long days, and that the diurnal pattern changes with photoperiodically induced testicular growth.

Journal

Nihon Chikusan Gakkaiho

Nihon Chikusan Gakkaiho 48 (9), 418-423, 1977

Japanese Society of Animal Science