Thyrotropin-releasing hormone (TRH) and vasopressin and oxytocin release: in vitro as well as in vivo studies

Rats euhydrated and dehydrated for two or four days were given intracerebroventricularly (i.c.v.) thyrotropin-releasing hormone (TRH) in a daily dose of 200 ng dissolved in 10 μl of 0.9 % sodium chloride.) A single dose of TRH administered to euhydrated animals was followed by a significant increase of the vasopressin content in the neurohypophysis and hypothalamus as well as of the hypothalamic oxytocin content. On the contrary, a single dose of TRH decreased the oxytocin content in the neurohypophysis. Under conditions of dehydration TRH distinctly restrained the decrease of vasopressin and oxytocin in the hypothalamus