Effect of cabergoline on metabolism in prolactinomas

Hyperprolactinemia has been implicated in the pathogenesis of obesity and glucose intolerance and is reportedly associated with an impaired metabolic profile. The current study aimed at investigating the effects of 12- and 60-month treatment with cabergoline (CAB) on metabolic syndrome (MetS) in patients with prolactinomas.

61 patients with prolactinomas (13 men, 48 women, 41 with microadenoma, 20 with macroadenoma), aged 34.4 ± 10.3 years, entered the study. In all patients, prolactin (PRL) and metabolic parameters were assessed at diagnosis and after 12 and 60 months of continuous CAB treatment. MetS was diagnosed according to NCEP-ATP III criteria.

Compared to baseline, CAB induced a significant decrease in PRL with complete normalization in 93% of patients after the 60-month treatment. At baseline, MetS prevalence was significantly higher in patients with PRL above (34.5%) than in those with PRL lower (12.5%) than the median (129 μg/l, p = 0.03). MetS prevalence significantly decreased after 12 (11.5%, p = 0.039) and 60 (5.0%, p = 0.001) months compared to baseline (28.0%). At both evaluations the lipid profile significantly improved compared to baseline. Fasting insulin and homeostatic model assessment of insulin resistance significantly decreased after 1 year of CAB (p = 0.012 and p = 0.002, respectively) and further improved after 60 months (p = 0.000). The visceral adiposity index significantly decreased after the 60-month treatment (p = 0.000) compared to baseline. At the 5-year evaluation CAB dose was the best predictor of percent decrease in fasting insulin (t = 2.35, p = 0.022).

CAB significantly reduces MetS prevalence and improves the adipose tissue dysfunction index. The improvement in PRL, insulin sensitivity and other metabolic parameters might reflect the direct effect of CAB.