THE BRAIN HISTAMINE (HA) AND PITUITARY LUTEINIZING-HORMONE (LH) LEVELS IN FEMALE RATS ANESTHETIZED WITH ETHER ON PROESTRUS

Levels of brain histamine (HA) and pituitary luteinizing hormone (LH) were determined in female rats anesthetized with ether in the afternoo n of proestrus. The rats after 6-hr ether anesthesia had an average HA concentration higher than that of nonanesthetized rats in the hypotha lamus, but not in the cortex or diencephalon. Ether-anesthetized rats also showed a higher LH level in the pituitary than that of nonanesthe tized rats, These findings agree well with our previous observation of an inhibited ovulation associated with a decrease in serum LH in fema le rats anesthetized with ether in the afternoon of proestrus. Further more, it is suggested that the release of pituitary LH into the circul ating blood is regulated by the level of HA in the hypothalamus.