Regulation of Secretion of Adrenotropic and Thyrotropic Hormones After Stalk Section

Abstract

Following section of the pituitary stalk in 61 rats, the hypophyseal-portal blood vessels did not regenerate. There was not only histological evidence of infarction and hypofunction of the pituitary gland, but the adrenals, thyroids and gonads were atrophic, indicating a subnormal release of pituitary tropic hormones. However, thiouracil feeding and exposure to cold, caused a small but definite increase in output of thyrotropic and adrenotropic hormones in operated animals. The data appears to indicate that the pituitary gland is capable of responding after stalk section, albeit less than normal, despite the absence of direct neural or neurovascular connections with the central nervous system and suggests that the circulating titer of peripheral hormones plays a major role in the regulation of pituitary tropic activity.