Showing papers by "Michael Menaker published in 1967"
TL;DR: The response of the testes of juvenile and adult hamsters to various photoperiods was examined and one of the few demonstrations of a response suitable for study in investigations of thePhotoperiodic control of testicular function in a laboratory mammal is demonstrated.
Abstract: The response of the testes of juvenile and adult hamsters to various photoperiods was examined. The testes of juvenile animals reached maturity regardless of the light cycle on which the animals were raised. However, the testes of adult hamsters required at least 12.5 hours of light per day to maintain spermatogenesis and prevent degeneration. This is one of the few demonstrations of a response suitable for study in investigations of the photoperiodic control of testicular function in a laboratory mammal.
338 citations
TL;DR: It has been shown that a 75-minute pulse of light per day is sufficient to produce a response normally produced only by long days in the sparrow Passer domesticus, and offers strong confirmation of B�nning's hypothesis concerning the mechanism of photoperiodic time measurement.
Abstract: A technique has been developed for effectively separating the direct inductive effect of a light signal from its effect on the phase of the rhythm of sensitivity to photoperiodic induction. With this technique it has been shown that a 75-minute pulse of light per day, when appropriately positioned with respect to the circadian activity cycle of the sparrow Passer domesticus, is sufficient to produce a response normally produced only by long days. The results cannot be interpreted in terms of a requirement of an absolute amount of either darkness or light and offer strong confirmation of Bunning's hypothesis concerning the mechanism of photoperiodic time measurement.
58 citations