Paradoxical response of plasma beta-endorphin to combined administration of TRH and GnRH in adrenal disorders.

The combined intravenous injection of TRH and GnRH elicited paradoxical responses of plasma beta-endorphin in active and successfully treated pituitary dependent Cushing's disease as well as in ectopic ACTH syndrome and in congenital adrenal hyperplasia. No response was observed in Cushing's syndrome due to adrenal tumours. It is concluded that an abnormal response to inappropriate releasing hormones cannot verify the existence of a pituitary corticotrophic microadenoma.