Effect of Nonsuckling Interval in the Ether-Induced Release of Immunoprecipitable Prolactin into the Plasma of the Lactating Rat

Abstract

Summary

The concentration of prolactin in the plasma of lactating rats increased from 24 to 74 ng/ml following acute ether stress as the length of the preceding period of nonsuckling diminished from 12 to 8 hr. In a second experiment the prolactin concentration increased from 24 to 79 to 104 ng/ml as the frequency of 10-min sucklings during a 12-hr period was altered from once at the end of the twelfth hr to once every 6 hr to once every 4 hr and the mothers then exposed to ether 12 hr after the last suckling. These results indicate that more frequent activation of the prolactin-releasing mechanism facilitates the subsequent release of prolactin in response to ether stress.

We are grateful to the NIAMDD Rat Pituitary Hormone Distribution Program for the rat prolactin radioimmunoassay kit, and to Mrs. Tanya McGee for technical assistance.