The influence of calcium infusion on serum prolactin in hyperprolactinemic women.

This study investigated the influence of calcium on serum prolactin (PRL) in hyperprolactinemic and healthy women. Previous studies have shown an inhibitory effect of Ca2+ on serum PRL, related to the degree of hypercalcemia. Serum PRL levels were measured by immunoradiometric assay (IRMA) in subjects before and one hour after 1375 mg Ca2+ injection. Serum PRL level was significantly decreased by calcium injection in hyperprolactinemic women (89.2 +/- 29.1 and 63.3 +/- 35.8 ng/ml; p < 0.01) while it was not significant (p > 0.05) in women with normal PRL levels (12.6 +/- 5.1 ng/ml and 11.3 +/- 4.0 ng/ml). These results indicate that acute alterations in serum calcium levels affect PRL secretion in hyperprolactinemic women.