Growth hormone and prolactin secretion in water-deprived chickens.

The deprivation of water for 12 or 24 hr increased the prolactin concentration in the plasma of immature chickens but had no effect on the circulating growth hormone (GH) level. The increase in plasma prolactin level reflected an increase in the basal rate of prolactin release from incubated hemipituitary glands and an increase in the responsiveness of the pituitary gland to hypothalamic releasing factors. The deprivation of water had no effect on basal level of pituitary GH release in vitro but abolished the stimulatory effect of the hypothalamus on in vitro GH secretion.