Effects of Nicotine on Human Luteal Cells In Vitro: A Possible Role on Reproductive Outcome for Smoking Women

We investigated the effect of nicotine and its methylated metabolite, N-methyl-nicotine (M-nicotine), on human luteal cells by measuring progesterone and prostaglandins (PGs) release from cultured cells and by testing Vascular Endothelial Growth Factor (VEGF)gene expression, an angiogenic factor strictlyinvolved in luteal pathophysiology. Primary cultures of human luteal cells were treated for 24 hours (h) with nicotine and M-nicotine (from 10(-6) to 10(-11) M) alone or combined with hCG 25 ng/ml; progesterone and PGs were assayed in the culture medium. In another group of experiments luteal cells were treated for 24 h with nicotine and M-nicotine (10(-7) M) in order to perform Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) on VEGF mRNA. Nicotine and M-nicotine negatively affected basal luteal steroidogenesis at all tested
concentrations while none of them was able to affect hCG-induced progesterone release. Both substances were able to significantly increase PGF2alpha release from luteal cells with a dose-related efficacy for M-nicotine. On the contrary, PGE2 release was significantly inhibited from both nicotine and its metabolite. Finally, nicotine was able to significantly increase VEGF mRNA expression, while M-nicotine was not. In conclusion nicotine and M-nicotine can induce a sort of luteal insufficiency by inhibiting progesterone release probably through the modulation of PGs system.