Phenogenetic analysis of prenatal development of the glucocorticoid function of the adrenals in silver foxes after long-term selection for domesticated behavior

The level of cortisol in serum and adrenals and its production by adrenals in vitro was studied by the radioimmune method in male and female silver fox embryos, starting from day 30 of pregnancy every five days. Pregnant females from a commercial population and an experimental population, which had been selected for domestic behavior, was used. It was shown that, at the end of the prenatal developmental stage, all investigated parameters of the glucocorticoid function of adrenals were significantly lower in embryos from selected mothers as compared to the unselected control group. The addition of adrenocorticotropic hormone into the incubation medium increased cortisol biosynthesis at all embryogenesis stages, but in the selected population the increase was less than that in the control group.