Eric L. Bittman

TL;DR: This chapter discusses the strategy of seasonal breeding, the role of photoperiod in timing the annual reproductive cycle, the hypothalamo-pituitary mechanisms that mediatePhotoperiodic regulation of estrous cyclicity, and the photoperperiodic pathway to luteinizing hormone (LH) pulse generator.

TL;DR: It is shown that implantations of brain grafts containing the fetal SCN reestablish circadian rhythms of locomotor activity in adult hamsters previously made arrhythmic by SCN lesions.

TL;DR: It is the collective view that the TIP has played, and will continue to play, a pivotal role in elucidation of the function of MEL in the photoperiodic control of seasonal mammalian responses and that the duration of the MEL signal is the critical parameter of the nocturnal secretion profile of the hormone for the phot operable control of several seasonally adaptive responses in mammalian species as diverse as hamsters and sheep.

TL;DR: It is concluded that the pineal mediates the reproductive response of the ewe to inductive photoperiods through its daily rhythm of melatonin secretion.

TL;DR: Even though circadian rhythms of locomotor activity are restored by SCN transplants, circadian endocrine rhythms are not reestablished and pineal melatonin concentration rose sharply during the late subjective night in control hamsters, but not in SCN-lesioned animals bearing behaviorally effective transplants.