Studies on the localization and the distribution of glucose-6-phosphatase in the liver cells of rats with several kinds of treatment

Abstract

The localization and the distribution of G-6-Pase activity in the liver cells of rats which received several kinds of treatment such as alloxan, cortisone, anabolic steroid or CCI4 were observed biochemically and by electron microscopic cytochemical technique. G-6-Pase activity in the liver cell of normal untreated rats was concentrated in R-ER, S-ER and inside of nuclear envelope. Increase in G-6-Pase activity as shown by deposit was especially pronounced on the increased S-ER at a stage of marked rise of blood sugar in the alloxan diabetic rats, while increase in size and number of the deposits was observed on the increased R-ER at a stage of normal level of blood sugar in the cortisone-treated rats. Based on such result, increase in G-6-Pase activity of the liver cell treated with alloxan was different from that treated with cortisone in distribution and localization. These findings suggest that G-6-Pase may be synthesized in R-ER and it may be related to carbohydrate metabolism in S-ER. In the liver cells of the rats treated with anabolic steroid, G-6-Pase was found in the increased R-ER and the deposit was increased in cristae mitochondriales 24 hours after treatment. Presence of mitochondrial G-6-Pase in agreement with the cristae might indicate that they are not the result of diffusion from microsome. However, metabolic significance of mitochondrial G-6-Pase remains entirely unknown. In the liver cell injured by CCI4, G-6-Pase activity was loccalized on the S-ER which increased locally with reticular formation. This phenomenon seems favorable to maintaining the metabolism in the injured hepatocyte.