Zinc may have a physiological role in regulating pituitary prolactin secretion.

We studied the in vitro influence of physiologically relevant zinc concentrations on the pituitary synthesis and secretion of prolactin (Prl). Zinc in concentrations between 1 and 10 microM reduced Prl secretion and, to a milder extent, synthesis, but not basal or stimulated growth hormone (GH) or LH release. At a supraphysiological concentration of 100 microM, zinc markedly decreased Prl synthesis and secretion, but increased LH secretion. The ability of a physiological zinc concentration to influence Prl secretion suggests that this trace element may have a role in the in vivo regulation of Prl release.