PRL and obesity due to melanocortin 4 receptor deficiency: Patient weight and BMI did not significantly differ across the study, FT4 was normal at all time points, testosterone was not different between patients with normal weight and those with overweight and obesity and none of female patients, in the fertile age, was on estrogen therapy. By contrast, the reduction of prolactin levels was significantly higher in the overweight/obese patients compared to those with normal weight.