Photoperiodic regulation of the hamster testis: dependence on circadian rhythms.
The testes of hamsters exposed to short days (10 hr of light per day) regress within 13 weeks. Administration of 7.5% deuterium oxide to hamsters lengthens the period of free running circadian activity rhythms by 2.2% and prevents testicular regression during short-day exposure. This consistent with predictions derived from an external coincidence model for photoperiodic time measurement: Deuterium oxide changes phase relationships between the light-dark cycle and the circadian system, the hamster's daily photosensitive phase is stimulated with light during short days, and the testes remain large. Conservation of the period of circadian rhythms within narrow limits has adaptive significance for hamster photoperiodism and for the occurrence and phasing of the annual reproductive cycle.
D000818:Animals; D002940:Circadian Rhythm; D006224:Cricetinae; D003903:Deuterium / Q000494:pharmacology; D008027:Light; D008297:Male; D009043:Motor Activity; D013737:Testis / Q000502:physiology*; D013997:Time Factors
D003903:Deuterium
Psychoneuroendocrinology. 1977;2(1):73-98
333494
Proc Natl Acad Sci U S A. 1977 Mar;74(3):1295-9
265574
Biol Reprod. 1977 Nov;17(4):493-8
562682
Science. 1977 Apr 15;196(4287):305-7
557840
Fed Proc. 1976 Oct;35(12):2339-46
964387
Biol Reprod. 1976 Oct;15(3):366-74
963161
J Exp Zool. 1975 Jan;191(1):111-20
1110345
C R Seances Soc Biol Fil. 1968 Jul;162(1):113-6
4235991
Annu Rev Physiol. 1973;35:305-28
4575164
Proc Natl Acad Sci U S A. 1972 Sep;69(9):2734-7
4506793
Endocrinology. 1974 Jul;95(1):195-205
4835879
J Neurovisc Relat. 1972;32(14):355-67
5025767
Science. 1967 Nov 17;158(3803):925-8
6054164