Regulation of gonadotropins and parathyroid hormone by nitric oxide

Nitric oxide has been recently recognized as an intra- and inter-cellular messenger. Animal studies have suggested a role for nitric oxide in the regulation of gonadotropin secretion. In this study of 14 healthy, young males, nitroglycerine administered sublingually was demonstrated to inhibit GnRH stimulated LH secretion from the pituitary (p < 0.05). There was no significant effect on GnRH stimulated FSH secretion. Nitroglycerine increased basal PTH levels (< 0.02), but had no significant effect on basal LH, FSH, TSH, cortisol, calcium, or prolactin levels. This study presents evidence that nitric oxide modulates LH and PTH secretion in humans.