Progesterone stimulates energy-dependent contraction of swollen heart mitochondria

Summary Progesterone stimulates the rate and efficiency of respiration-dependent contraction of heart mitochondria in nitrate salts at alkaline pH. Ion extrusion under these conditions is normally slow and inefficient due to the elevated permeability of the membrane to monovalent cations through a putative uniport pathway. Progesterone also inhibits passive swelling under these conditions and appears to act by restricting cation influx through the uniport pathway.This study was supported in part by United States Public Health Service grant No. HL09364.