Effect of Nicotine Administration on Estrous Cycle in Female Albino Rats

Although it has been emphasized that cigarette smoking is not always synonymous with nicotine administration, the toxic effect of cigarette has often been associated with the nicotine content in cigarette. Cigarette is known to contain toxic, carcinogenic, mutagenic, growth retardative and immunosuppressive compounds. Epidemiologic studies have clearly indicated that women who smoke suffer a lowering of fertility. Is this due to the nicotine in cigarette? The effect of nicotine administration on fertility in female albino rats was investigated. Using estrus cycle and ovulation as parameters of fertility, the effect of daily 0.5mg/kg nicotine administration and equal amount of 0.9% Normal Saline, on the phases, length of the cycle and number of ova released were determined. The possible mode of action was also determined using ovulatory blocking doses of Nembutal and varying doses of ovine leutinizing hormone oLH (12.5, 25 and 50 mg/kg). Nicotine (0.5mg/kg) increased the length of estrous cycle with the introduction of a new phase -“subestrous”. Ovulation was delayed and the number of ova released reduced as in women smokers. This study suggests a likely direct action of nicotine on the ovary. Keywords: Nicotine administration, estrus cycle, ovulationNigerian Journal of Health and Biomedical Sciences Vol. 6 (2) 2007: pp. 21-2