Evaluation of Seasonal Serum Level of Estradiol and Progesterone Hormones in Iranian Female Caucasian Viper

Steroids hormones have a basic role in animals' reproductive activity and their secretion amounts are changed during the year with animal physiological conditions. There is no study reporting Iranian female snake's hormones controlling reproductive activity. In this study the estradiol (E2) and progesterone (P4) hormones level in serum samples of 26 female Caucasian vipers were examined by electrochemiluminescence (ECL). The results show the average concentration of estradiol (E2) hormone in the autumn (157.2±47.53 nmol/ Lt) is less than the early winter (December-January), 318.33±156nmol/l (p≤0.1) and again the concentration of this hormone reduced in the summer, 188.94±33.57 nmol/Lt (p≤0.78). The average concentration of P4 hormone in the autumn was 0.45±0.14nmol/Lt and in winter was 0.96±0.57 nmol/Lt, that show increasing process (p≤0.22). The average concentration of this hormone is decreasing in the summer, 0.82±0.23 nmol/Lt as compared to the winter (p≤0.78). In the fertile snacks the amount of serums estradiol is increased during the vitellogenesis and progesterone is increased during pregnancy and the amount of these hormones is low throughout the year in unfertile snacks. According to these hormones changing during the seasons it seems that the Iranian Caucasian viper from Lar area in Tehran province, during the winter season is in the vitellogenesis phase and summer is the pregnancy time and the autumn is the time of postpartum. Although the maximum amount of progesterone is inconsistent with the winter but like this case is reported before.