THE ROLE OF GENETIC-VARIABILITY IN THE HORMONAL ADAPTATIVE MECHANISM .1. THE EFFECT OF VARIOUS HOMOZYGOSITY LEVEL ON THE ADRENAL-CORTEX HORMONE CONCENTRATIONS (CORTICOSTERONE AND ALDOSTERONE) IN THE BLOOD-SERUM OF RATS EXPOSED TO 2 TYPES OF STRESS

In rats of various inbred level (%): 0, 37, 50 and 91 exposed to physical stress (3 d starvation and 3 h swimming) adrenal cortex hormone concentrations: aldosterone (ALD) and corticosterone (Cort), were studied by RIA method in blood serum. The initial, parental population (0% inbred) was F1 hybrids between wild Norway rats (Rattus norvegicus Erxleben) and albino outbred Ipf:RIZ rats. A significant relationship between inbreeding coefficient of an animal and ALD and Cort concentrations was found, and it was expressed by significant (p less-than-or-equal-to 0,01) concentration decrease in both hormones as the homozygosity was increasing: ALD followed a quadratic function, Cort a cubic function. Effect of stress was inverse of that of inbreeding, on significant (p less-than-or-equal-to 0,01) corticosteroids increased. Sex determined ALD and Cort concentrations as well. ALD concentration was significantly higher (p less-than-or-equal-to 0,01) in males in comparison with females. Cort concentration was inversely dependent; being significantly (p less-than-or-equal-to 0,01) higher in females than in males. Interaction between the factors studied (inbred, sex, stress) also influenced ALD and Cort concentrations.