Endocrine Abstracts

Introduction: The effects of hyperprolactinemia on metabolic parameters are not conclusive and a few data evaluating adiponectin levels in prolactinoma and idiopathic hyperprolactinemia exist. The aim of this study is to evaluate effects of hyperprolactinemia on body weight, insulin resistance, β cell function, leptin and adiponectin levels in premenopausal women with hyperprolactinemia.

Methods and design: Forty premenopausal women with prolactinoma or idiopathic hyperprolactinemia were compared to 41 age-matched healthy premenopausal women with regard to body weight, BMI, waist and hip circumferences, waist to hip ratio, fasting plasma glucose, insulin, insulin resistance measured by homeostasis model assessment-insulin resistance index (HOMA-IR), β cell function measured by homeostasis model assessment-β index (HOMA-β), leptin and adiponectin levels.

Results: Plasma insulin levels, HOMA-IR and HOMA-β were significantly higher in hyperprolactinemic women than the control group (P=0.012, 0.01 and 0.005, respectively). The other parameters were not significantly different from the control group. There was a positive correlation between prolactin levels and fasting plasma glucose (P=0.025, r=0.354).

Conclusions: The results of the study showed that high prolactin levels may be associated with hyperinsulinemia and insulin resistance in premenopausal women. This effect seems to be independent from body weight, leptin and adiponectin levels. High prolactin levels may directly stimulate insulin secretion from pancreas and directly cause hepatic and whole-body insulin resistance. Correlation between prolactin and fasting plasma glucose suggests an increased hepatic glucose output by prolactin and thus may indicate an increased hepatic insulin resistance.