In 7 patients aged from 21 to 33 years (average age 24.6 years) with hyperprolactinemic galactorrhea a stimulation test with GnRH-TRH or arginine-GnRH-TRH was performed. The serum levels of LH, FSH, PRL, HGH, TSH and total thyroxine (T4) were determined by RIA, the thyroxine binding capacity (TBC) by radio agent assay. The free thyroxine index (FT4-I) was calculated. An adenoma of the pituitary gland was diagnosed in 3 patients by X-ray of sella turcica. In all patients there were disturbances of the menstrual cycle. Independent of the existence of an adenoma of the pituitary gland in all patients with high basal levels. PRL could not have been shown stimulated by TRH. On the other hand it could be shown that despite of high basal PRL-levels in serum there was a normal stimulation of the gonadotrophs in 5 patients. Out of one patient the stimulation of the thyreotropic cells of pituitary by TRH was normal, too, whereas there was no or an inadaquate stimulation of HGH by arginine in all patients.--T4, TBC and FT4-I showed no deviation from the normal range.