Macroprolactinoma and metabolic involvement

Prolactinomas are the most frequent functioning tumors of the pituitary gland. Hyperprolactinemia is associated with systemic effects like weight gain, metabolic syndrome, insulin resistance, and chronic low-grade inflammation. Some studies showed improvement in BMI, LDL and HOMA-IR after prolactin normalizing treatment. We conducted an analytical cross-sectional study involving forty patients followed for confirmed prolactinoma. Clinical and biological data related to metabolic syndrome were collected retrospectively from the files. Overweight or obesity was noted in 22 patients over 40 (55%). A positive correlation was detected between BMI and the size of the tumor ( r = 0.11) but not statistically significant ( P = 0.4). Six cases of prediabetes and one case of “de novo” diabetes were diagnosed on the biological assessment. For euthyroid patients, there were 4 cases of hypercholesterolemia and 3 cases of hypertriglyceridemia. For those with hypothyroidism, seven had hypercholesterolemia and 7 others had hypertriglyceridemia. There is a relationship between obesity and the activity of lactotropic tumor cells. This being explained by the reduction in the availability of brain dopamine receptors and therefore dopamine which having a satietogenic effect and stimulating metabolism. Other hypotheses are mentioned like the reduction of adiponectin levels, leptin resistance and hypogonadism [1] . Excess of prolactin is also related to carbohydrate intolerance and hyperinsulinism leading to insulin resistance independently of BMI [2] , [3] .