The hyperprolactinemic polycystic ovary syndrome may not be an distinct entity.

Thirteen women with hyperprolactinemia and clinical stigmata of the polycystic ovary syndrome (PCO) had their serum prolactin (PRL) response to thyrotropin-releasing hormon (TRH) compared with two other groups of PCO. One PCO group had an elevated ratio of basal luteinizing hormone (LH) to follicle-stimulating hormone (FSH), and another had a normal ratio of basal LH to FSH. The PRL response to TRH was similar in hyperprolactinemic PCO and elevated LH PCO, and both were significantly greater than normal LH PCO and normal women. This suggests the hyperprolactinemic polycystic ovary (HPCO) is probably produced by similar central and/or peripheral mechanisms that result in the production of an elevated serum LH. These two features are probably associated in a common pathophysiologic mechanism. The HPCO syndrome does not appear to be a distinct entity but clinically must be differentiated from other causes of mild hyperprolactinemia.