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Inhibitory effect of calcium on serum prolactin
Insights
Calcium infusions significantly lowered serum prolactin (Prl) in most subjects, regardless of calcium metabolism disorders. This suggests a potential role for dopamine release in the hypothalamus, influencing Prl levels.
Area of Science:
- Endocrinology
- Neuroendocrinology
- Calcium Metabolism
Background:
- Serum prolactin (Prl) regulation involves complex hormonal and neural pathways.
- Calcium (Ca) plays a crucial role in various physiological processes, including neurotransmitter secretion.
- Disorders of calcium metabolism can impact endocrine function.
Purpose of the Study:
- To investigate the effect of calcium infusions on serum prolactin levels in children.
- To explore the relationship between calcium metabolism and prolactin secretion.
- To elucidate the potential mechanisms underlying observed changes in prolactin.
Main Methods:
- Administered calcium infusions to normal controls and children with various calcium metabolism disorders.
- Measured serum prolactin (Prl) levels before and after calcium infusion.
- Monitored related hormones including calcitonin (CT) and parathyroid hormone (PTH).
Main Results:
- Calcium infusion induced a significant decrease in serum prolactin in the majority of subjects studied.
- The observed prolactin decline was not directly attributable to concurrent changes in calcitonin or PTH levels.
- Subjects included those with secondary hyperparathyroidism, idiopathic hypoparathyroidism, and anticonvulsant-induced hypocalcitoninism.
Conclusions:
- Calcium administration appears to inhibit serum prolactin secretion in humans.
- The findings suggest a potential role for calcium in modulating hypothalamic dopamine release, which may mediate the prolactin suppression.
- Further research is warranted to confirm the dopaminergic link and its clinical implications.
Abstract:
The effect of calcium (Ca) infusions on serum prolactin (Prl) was studied in normal controls and children with disorders of Ca metabolism: Three patients with secondary hyperparathyroidism (vitamin D deficiency rickets), 2 children with idiopathic hypoparathyroidism, 13 epileptic patients with anticonvulsant drug induced inhibition of calcitonin (CT) secretion and 1 patient with vitamin D resistant rickets with normal CP and low PTH secretion. Ca induced a significant decline of serum Prl in most subjects which could not be explained by the associated increase of CT or decrease of iPTH. The important role of Ca for the in vitro secretion of dopamine has been established for a long time. It is speculated that the inhibitory effect of Ca infusion or serum Prl may be due to dopamine release from nerve tracts in the hypothalamus.