الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The present study was carried out to explicate the influence of heat and cold stress on the reproductive endocrine behavior by determining the levels of serum (FSH, LH, estrogen, progesterone and testosterone) hormones of albino rats (Rattus-rattus). Cortisol hormone was also estimated. The change in temperature may also be responsible for a variety of physiological stress responses in organisms, which are often associated with enhanced generation of reactive oxygen species (ROS) leading to oxidative damage. In the present study, we revealed the effect of heat and cold stress on activity of some antioxidant enzymes including superoxide dismutase (SOD) and catalase (CAT) and also reduced glutathione (GSH). Hyperthermia and hypothermia were investigated in adult sixty male and female albino rats (thirty male and thirty female rats) divided into five groups (n=6); 12 (6 male and 6 female rats) were subjected to high temperature (35 ± 1°C) for 30 successive days,12(6 male and 6 female rats) were maintained under normal environmental conditions (25±1°C) for 20 days then transfered into another room where they were subjected to extreme high temperature (40±1°C),12 (6 male and 6 female rats) were subjected to low temperature (10±1°C) for 30 successive days,12 (6 male and 6 female rats) were maintained under normal environmental conditions (25±1°C) for 20 days then transfered into another room where they were subjected to extreme low temperature (7±1°C). while rats of the control group were maintained under normal environmental conditions (25±1°C) for 30 days. Sexual endocrine response to heat and cold exposure was assessed by determining the levels of serum (FSH, LH, estrogen, progesterone and testosterone hormone) and cortisol hormone was also evaluated by Vitek Immunodiagnostic System Assay (VIDAS). The results revealed a significant (P<0.05) effects of heat stress on the sexual hormones concentrations There was an elevation in FSH, LH, progesterone and testosterone hormone levels in both males and females under heat stress either chronic or acute, a decline in estrogen in females and cortisol hormone level in both male and female rats under chronic and acute heat stress, while the estrogen hormone levels remains without significant difference in male rats. The results also showed that the activities of CAT and SOD were significantly elevated, increment; GSH there were a significant increase in females but a significant decrease in males under heat stress. In conclusion : This study showed that heat and cold stress had been implicated in changes in sexual and endocrine system; then reproductive retardation, heat and cold stress also causes alterations in antioxidant defense system. .