Prolactin is frequently increased in sarcoidosis, between 3% and 32% of cases have hyperprolactinemia  this frequently leads to amenorrhea , galactorrhea , or nonpuerperal mastitis in women. It also frequently causes an increase in 1,25-dihydroxy vitamin D, the active metabolite of vitamin D , which is usually hydroxylated within the kidney, but in sarcoidosis patients hydroxylation of vitamin D can occur outside the kidneys, namely inside the immune cells found in the granulomas the condition produces. 1,25-dihydroxy vitamin D is the main cause for hypercalcemia in sarcoidosis and overproduced by sarcoid granulomata. Gamma-interferon produced by activated lymphocytes and macrophages plays a major role in the synthesis of 1 alpha, 25(OH)2D3.  Hypercalciuria (excessive secretion of calcium in one's urine) and hypercalcemia (an excessively high amount of calcium in the blood) are seen in <10% of individuals and likely results from the increased 1,25-dihydroxy vitamin D production.