Secretory dynamics of bioactive and immunoreactive prolactin in polycystic ovary syndrome

To further investigate prolactin (PRL) secretion in polycystic ovary syndrome (PCO), the authors evaluated immunoreactive (immuno) and bioactive (bio) PRL levels in the basal state and in response to provocative testing with intravenous dopamine (DA), metoclopramide (MCP), and gonadotropin-releasing hormone (GnRH), before and after disulfiram. Basal measurements of immuno-PRL, bio-PRL, and the ratio of bio/immuno-PRL were similar in PCO and controls. The immuno-PRL decrement after DA was greater than that of bio-PRL in both groups (P less than 0.05). After MCP, immuno-PRL increased more than bio-PRL in PCO (P less than 0.01), and this immuno-PRL increment was greater than that of controls (P less than 0.05). Bio-PRL and immuno-PRL increased after GnRH in PCO, but not controls, and these responses were inhibited by disulfiram. These data confirm PRL hypersecretion in some women with PCO, which is better expressed by immunoreactivity than bioactivity. Given the assay systems and patients studied, bioactivity