Effects of nicotine administration on elemental concentrations in mouse granulosa cells, maturing oocytes and oviduct...

A normal maturation of the oocytes is dependent upon, among other things, normally functioning granulosa and corona radiata cells. Analyses performed during human in vitro fertilization programs have revealed that, in smokers, ovarian functions are affected and that smokers have a decreased fertilization rate. Further, animal studies have indicated that nicotine can reach the genital tractus, and that nicotine administration interferes with oocyte maturation, fertilization and early pregnancy. We applied X-ray microanalysis to monitor whether nicotine administration changed the ionic balance of cells in the reproductive tract (granulosa cells, oocytes and oviduct epithelial cells). The animals were given nicotine in the drinking water at a concentration of 108 mumol/l. After 15 days the animals were superovulated, ovaries and oviducts were frozen, and thick cryosections were prepared for energy-dispersive X-ray microanalysis. In the granulosa cells, the concentrations of Na and Cl increased after nicotine treatment, while the K concentrations decreased resulting in an increased Na/K ratio. The treated oocytes had a higher K concentration and a decreased Na/K ratio compared to the controls. In the epithelial cells of the oviduct, the concentrations of Na and K decreased after nicotine treatment without any changes in the Na/K ratio. Thus, heavy nicotine administration to mice causes significant changes in the ionic composition of the granulosa cells, the ovarian oocytes and the oviduct epithelium.