Maintenance of testicular function in Turkish hamsters: interaction of photoperiod and the pineal gland.
Adult male Turkish hamsters maintained testicular function when exposed to photoperiods of 15, 16, or 17 h of light per day. Photoperiods of less than 15 or greater than 17 h of light per day induced a rapid and complete testicular regression. As pinealectomy had been shown by others to induce testicular regression in long-day Turkish hamsters, we thought that regression on 18 or more h of light might be based on the inability of the pineal to generate a daily rhythm of melatonin in production and release. This proved not to be the case. Animals exposed to 14-18 and 20 h of light per day had a robust nocturnal melatonin rhythm.
S M
SM
Hong
M D
MD
Rollag
M H
MH
Stetson
D000818:Animals; D002940:Circadian Rhythm; D006224:Cricetinae / Q000502:physiology*; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D009929:Organ Size; D010507:Periodicity; D010870:Pineal Gland / Q000502:physiology*; D013737:Testis / Q000033:anatomy & histology / Q000502:physiology*
D008550:Melatonin