Twenty-four hour secretory pattern of growth hormone in hyperprolactinemic women with pituitary microadenoma.

The 24-h secretory pattern of GH was evaluated in normal women (n = 4) and hyperprolactinemic-amenorrheic women with pituitary microadenoma (n=6). Serum GH concentrations significantly differed according to the time of day, and there were nocturnal rises in normal women and hyperprolactinemic women. However, episodic fluctuations in serum GH levels were almost absent during the day time in hyperprolactinemic women, and the mean 24-h GH concentration was significantly lower in these women than in normal women. Thus, GH secretion was diminished in hyperprolactinemic women with pituitary microadenoma, though a nocturnal increase in GH secretion continued.