REGULATION OF GONADOTROPINS AND PARATHYROID-HORMONE BY NITRIC-OXIDE

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