Effects of some steroid hormones on Ca2+ transport and oxidative metabolism of isolated mitochondria

Effects of prednisolone, estradiol, and testosterone on the transport of Ca²⁺ and the respiration induced by it in the heart and liver mitochondria of rats were studied. Prednisolone and testosterone were found to reduce the Ca-accumulating capacity of the mitochondria, the rates of ion entry and exit, and the rate of Ca²⁺-induced respiration. Estradiol, while inhibiting Ca²⁺ transport across mitochondrial membrane, did not influence the respiration in the phase of Ca²⁺ absorption, but accelerated it in the phase of ion exit. These data suggest that due to their lipophilic properties, the steroids become incorporated in the mitochondrial membrane, thereby changing its viscosity and permeability and limiting the mobility of transmitter proteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 616–618, December, 1994