Abstract
Summary
A daily rhythm of serum corti-costerone persists in 31 day old immature female rats in which pseudopregnancy has been induced by means of 25 IU pregnant mare's serum gonadotrophin (PMS) given at 26 days of age. There is, in addition, a daily rhythm of progesterone in 31-day old controls with a rise during the day and a fall during the dark portion of the photoperiod. PMS-injected rats had a much higher level of progesterone but no rhythm.
Supported by NSF Grant No GB 35730.
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