Estrogen Accelerates Gonadal Recrudescence in Photo-Regressed Male Siberian Hamsters
نویسندگان
چکیده
منابع مشابه
Long-term persistence of male copulatory behavior in castrated and photo-inhibited Siberian hamsters.
Gonadal steroids are essential for the long-term maintenance of the full repertoire of sexual behavior in male rodents. Typically, all individuals of several species cease to display the ejaculatory reflex within a few weeks of castration. The present study documents the persistence of the ejaculatory reflex 19 weeks after orchidectomy in 40% of male Siberian hamsters maintained in long or shor...
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Short days induce multiple changes in reproductive and immune function in Siberian hamsters. Short-day reproductive inhibition in this species is regulated by an endogenous timing mechanism; after approximately 20 weeks in short days, neuroendocrine refractoriness to short-day patterns of melatonin develops, triggering spontaneous recrudescence of the reproductive system. It is unknown whether ...
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Mounting a sickness response is an energetically expensive task and requires precise balancing of energy allocation to ensure pathogen clearance while avoiding compromising energy reserves. Sickness intensity has previously been shown to be modulated by food restriction, body mass, and hormonal signals of energy. In the current study, we tested the hypothesis that sickness intensity is modulate...
متن کاملPhotoperiodic Influences on Ultradian Rhythms of Male Siberian Hamsters
Seasonal changes in mammalian physiology and behavior are proximately controlled by the annual variation in day length. Long summer and short winter day lengths markedly alter the amplitude of endogenous circadian rhythms and may affect ultradian oscillations, but the threshold photoperiods for inducing these changes are not known. We assessed the effects of short and intermediate day lengths a...
متن کاملGonadal hormone-dependent and -independent regulation of immune function by photoperiod in Siberian hamsters.
Siberian hamsters (Phodopus sungorus) exhibit changes in reproductive and immune function in response to seasonal variations in day length. Exposure to short days induces gonadal regression and inhibits testosterone secretion. In parallel, short days enhance immune function: increasing leukocyte numbers and attenuating cytokine and behavioral responses to infection. We examined whether photoper...
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ژورنال
عنوان ژورنال: Endocrinology
سال: 2002
ISSN: 0013-7227,1945-7170
DOI: 10.1210/en.2002-220569