Insulin resistance and androgen levels in eugonadic and hypogonadic women with prolactinoma

Hyperprolactinemia is the most common endocrinologic disorder in causing menstrual irregularities. Although the correlation between hyperprolactinemia and menstrual dysfunction is widely known, the etiology of menstrual cycle disorders is not profoundly understood in patients with prolactinoma. We aimed to investigate the correlation between prolactin levels and insulin resistance and hyperandrogenism in patients with prolactinoma.

Sixty-four patients with microprolactinoma and 33 healthy women were enrolled. Thirty-six of these patients with prolactinoma (group 1) had an estradiol (E2) level under 30 pg/mL, and 28 (group 2) had an E2 level greater than 30 pg/mL. Blood samples were drawn to measure the levels of the following hormones: Follicle stimulating hormone (FSH), luteinizing hormone (LH), E2, prolactin (PRL), total testosterone (TT), androstenedione (AS) and dehydroepiandrostenedione sulphate (DHEAS). Body Mass Index (BMI of ≥30 kg/m2) was excluded from the study. Insulin resistance (IR) was calculated by the HOMA-IR.

BMI was higher in patients with prolactinoma than the control group (P=0.02, P=0.025, respectively). IR and glucose intolerance existence were higher in patients with prolactinoma (P=0.007, P=0.097, respectively) than the healthy women, but these differences did not exist between eugonadic and hypogonadic women with prolactinoma (P=0.020, P=0.032, respectively, Bonferroni correction). TT and AS were higher in eugonadic women with prolactinoma than the control group (P=0.004, P=0.003, Bonferroni correction, respectively).

Our study revealed that the relationship between hyperprolactinemia and IR/glucose intolerance is irrespective of gonadal status in women with prolactinoma. Also, the study concluded that hyperandrogenism may be a cause of menstrual dysfunction in eugonadic women with prolactinoma.