A quantitative cytochemical study of acid phosphatases in hepatocytes of different ploidy classes from aging rats

A quantitative cytochemical study of isolated hepatocytes from young, middle-aged and old adult rats has shown a doubling of acid naphthol AS-BI phosphatase activity as the hepatocytes shift from the diploid to the tetraploid state, and an overall increase in activity in cells from old animals. There was a complete inhibition of all acid phosphatase activity with 10(-2)M sodium molybdate, but only a 90% inhibition in hepatocytes from livers of rats of 12-25 months-old animals with 10(-2)M sodium fluoride, the resistant activity possibly representing adenyl cyclase activity. In contrast, 10(-2)M ouabain inhibited 70-80% of the activity in hepatocytes from 12-15-months-old animals, this level of inhibition decreasing with increasing age, and implying a decrease in transport ATPase activity and an increased lysosomal phosphatase activity with increasing age of the rats.