After PRL normalization, HCT and Hb levels significantly improved in men with microprolactinoma (median HCT 42.3 [1.8] vs. 44.0 [1.6] % and median Hb 14.5 [0.6] vs. 15.1 [0.7] g/dl, both p < 0.05) as well as in those with macroprolactinoma (median HCT 40.2 [3.7] vs. 43.9 [2.2] % and median Hb 13.9 [2.0] vs. 15.1 [1.5] g/dl, both p < 0.001) (Table 4). This evidence concerns the gene GSTM1 and Microprolactinoma.