OBJECTIVE: The aim of this study was to compare the changes in plasma levels of hormones involved in modulation of the immune system function after exposure to stress in two rat strains with different susceptibility to immunoantigens. METHODS: Adult rat males of Lewis (LEW) and Fischer 344 (FIS) strains were exposed to restrain stress for 2 hours and blood samples were collected during stress exposure. Other groups of animals were exposed to restrain stress for 2 hours and sacrificed 3 hours later for blood and organ collection. Corticosterone, testosterone, dehydroepiandrosterone, 17beta-estradiol and progesterone were estimated by radioimmunoassay, epinephrine and norepinephrine levels were determined by radioenzymatic method. RESULTS: The levels of plasma corticosterone and catecholamines were significantly higher during stress exposure in FIS as compared to LEW rats. Greater decrease of testosterone levels and higher levels of estradiol were noted after exposure to stress in LEW rats. Higher values of progesterone plasma levels were noted in FIS rats after stress. CONCLUSIONS: These results demonstrated the differences in the response of catecholamines, adrenal and gonadal steroids after exposure to stress in LEW and FIS rats with lower levels of hormones with anti-inflammatory action in LEW rats.
OBJECTIVE: The aim of this study was to compare the changes in plasma levels of hormones involved in modulation of the immune system function after exposure to stress in two rat strains with different susceptibility to immunoantigens. METHODS: Adult rat males of Lewis (LEW) and Fischer 344 (FIS) strains were exposed to restrain stress for 2 hours and blood samples were collected during stress exposure. Other groups of animals were exposed to restrain stress for 2 hours and sacrificed 3 hours later for blood and organ collection. Corticosterone, testosterone, dehydroepiandrosterone, 17beta-estradiol and progesterone were estimated by radioimmunoassay, epinephrine and norepinephrine levels were determined by radioenzymatic method. RESULTS: The levels of plasma corticosterone and catecholamines were significantly higher during stress exposure in FIS as compared to LEW rats. Greater decrease of testosterone levels and higher levels of estradiol were noted after exposure to stress in LEW rats. Higher values of progesterone plasma levels were noted in FIS rats after stress. CONCLUSIONS: These results demonstrated the differences in the response of catecholamines, adrenal and gonadal steroids after exposure to stress in LEW and FIS rats with lower levels of hormones with anti-inflammatory action in LEW rats.