K L Jorgenson

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The electrophysiological effects of histamine on neurons of the hypothalamic arcuate nucleus of the female rat were tested with extracellular single unit recordings in an in vitro slice preparation. Histamine increased the spontaneous neuronal firing rate in 63% of the arcuate cells tested. An inhibitory response to histamine was seen in only one of the 117(More)
The purpose of these experiments was to determine whether daily gonadotropin surges that occur in intact or ovariectomized hamsters kept in short days (less than 12 h of light/day) are manifest because of extremely low levels of steroids. Hamsters were ovariectomized and placed in 16L:8D or 10L:14D. After 10-13 weeks, animals in each photoperiod were(More)
Anestrous hamsters exhibit daily afternoon gonadotropin and progesterone surges, but little estrogen secretion. In the first experiment, short day anestrous females were transferred to long days to detect hormonal changes associated with recovery of cyclicity. Morning and afternoon blood samples were taken at increasing durations in long days. Females(More)
Female golden hamsters exposed to short photoperiods become anestrous and exhibit daily surges of gonadotropins and progesterone. Since little is known about the transition between the cycling and anovulatory states, the following experiments were done to determine whether there are hormonal changes that precede cessation of estrous cyclicity. Females(More)
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