THE OXYTOCIN SECRETORY RESPONSE DURING SUCKLING IN THE HYPOOSMOLAR LACTATING RAT

Secretion of oxytocin into the peripheral circulation of rats is stimu lated by suckling and inhibited by hypoosmolality. We compared the oxy tocin secretory response to suckling in 1 week post partum lactating r ats rendered hyponatremic for 48 h to matched lactating normonatremic cohorts. Pituitary content of oxytocin and peripheral oxytocin secreto ry responses to suckling were equivalent in normonatremic and hyponatr emic animals. We conclude that induction of sustained hyponatremia for 48 h does not inhibit suckling-induced oxytocin release in lactating rats.