AJP - Endocrinology and Metabolism, Vol 247, Issue 5 675-E680, Copyright © 1984 by American Physiological Society
Prolactin stimulation of parathyroid hormone secretion in bovine parathyroid cells
L. Magliola and L. R. Forte
Previous studies have suggested that prolactin (PRL) may affect calcium
(Ca) homeostasis by an action on vitamin D metabolism. In this study, the
effects of PRL on parathyroid hormone (PTH) secretion were investigated in
dispersed bovine parathyroid cells (PTC). PRL (0.013-1.3 microM) caused
concentration-dependent increases in PTH secretion. PRL-stimulated PTH
release was apparent as early as 1 h and was progressive thereafter for up
to 3 h. PRL enhanced PTH release over a wide range of ambient Ca
concentrations (0.5-2.0 microM). Ovine and rat PRL were more effective than
bovine PRL in stimulating PTH secretion. This effect was apparently
specific for PRL because neither ovine nor bovine growth hormone stimulated
PTH secretion. PRL-stimulated PTH release was not mediated through the
beta-adrenergic or dopaminergic receptor systems of PTC and was not
associated with increased adenosine 3',5'-cyclic monophosphate (cAMP)
levels. This study demonstrated a direct effect of PRL to stimulate PTH
secretion in vitro. Although these data do not provide evidence for an
effect of PRL in vivo, we suggest a mechanism by which PRL may influence
parathyroid function and Ca homeostasis in the bovine species.
