Nicotine given intracerebroventricularly does not inhibit the preovulatory surge of LH and PRL secretion in female rats.

To determine the effect of nicotine on LH and PRL secretion, nicotine bitartrate (nicotine) dissolved in saline was administered at 1400 h, just before the critical period for the preovulatory surge of LH and PRL secretion, either intracerebroventricularly (icv) or intravenously (iv) in female rats in proestrus. Nicotine neither at a dose of 5 microg nor at a dose of 10 microg injected icv at 1400 h caused significant changes in the surge of LH and PRL secretion. When nicotine was given iv at a dose of 100 microg, a significant decrease in LH and PRL concentrations occurred immediately, lasting for 2 h.