Quantitative high resolution light and EM autoradiography of fluorophosphate-esterase in developing mouse liver
The distribution and concentration of fluorophosphate reactive (FPR) esterases in the liver of developing and adult mice was determined quantitatively from light and electron microscope autoradiograms of liver reacted with 3H - diisopropylfluorophosphate (3H-DFP) an irreversible inhibitor of carboxylesterases.The majority of labeled cells in the liver of 2, 8, 14 and 28- day-old mice and in adult mice (60-180 days old) were hepatocytes, but in the liver from 2-day-old mice and to a lesser extent 8-day-old mice, the autoradiographic silver grains were also concentrated over granulocytes of the intrahepatic hemopoietic population.Quantitative measurements of grain density (developed silver grains/unit area) in light microscope autoradiograms revealed an increase in the predominantly cytoplasmic concentration of FPR esterase sites in hepatocytes from 137o of the adult concentration in 2-day-old mice, to 497, and 78% of the adult concentration in 8- and 14-day-old animals, respectively.