[The postnatal ontogenetic characteristics of adrenal function in female water voles Arvicola terrestris with different fur colors].

Studies have been made of the effect of colour mutation on the development of the adrenals in female aquatic voles. Colour mutation in homozygote results in retarded growth rate of the whole body and the adrenals, as well as in postnatal changes in the dynamics of corticosteron content in the blood. Obviously, the effect of colour mutation on plasma concentrations of corticosteron is realised mainly via extra-adrenal mechanisms since no differences were found in corticosteron production by the adrenals and in the adrenal reaction to ACTH (5 U/g of the adrenals) in vitro in growing aquatic voles. During postnatal life, mutant black females exhibited lower sensitivity of the adrenals to the inhibitory influence of estradiol (40 ng/100 mg of the adrenals) as compared to wild phenotype animals.