Levels of glucose and insulin during twenty-four hours in hyperprolactinemic women with pituitary microadenoma.

Excursions of plasma glucose and insulin throughout the 24-hour metabolic clock were evaluated in hyperprolactinemic women with pituitary microadenoma. The glucose response to food intake and 24-hour excursion of plasma glucose were not altered in hyperprolactinemic women compared to normal women. Premeal and 24-hour insulin levels were significantly increased in hyperprolactinemic women, though fasting insulin levels were not. Postprandial insulin increments appeared to be more sustained in these patients compared to normal women, though the difference was not statistically significant. And therefore the increased 24-hour concentration of insulin in hyperprolactinemic women appears to be due to the sustained insulin response to meals and increased premeal insulin levels. A slight resistance to insulin was observed in hyperprolactinemic women. That the 24-hour excursion of plasma glucose is not altered in hyperprolactinemic women in the face of decreased sensitivity to insulin may be accounted for by the increased insulin secretion.