Ultrastructural as well as ultracytochemical observations were made On rat hepatic parenchymal cells after glucagon perfusion (200-600μg/50ml of Krebs-Ringer's bicarbonate solution) via portal vein. The irregularly shaped lysosomes, such as rod-shaped, dumbbell-shaped or the ones with tails, were observed even 5 min after glucagon perfusion. The acid phosphatase ctivity was clearly positive in the matrix of these unusual structures. These irregularly shaped lysosomes were considered to be the sheet-like extensions from the original body of the pre-existing lysosomes. In connection with the presence of the irregularly shaped lysosomes an autophagic process was evident and the double-membraned (inner and outer) autophagolysosomes were frequently observed. Results obtained in the present investigation indicate that the autophagolysosomes are formed by the wrapping mechanism of the irregularly shaped lysosomes in the hepatic parenchymal cells of the rat following glucagon administration.
In the present investigation comparison of the activity of oxidoreductases (succinate-ferricyanide reductase, cytochrome c-ferricyanide reductase, NADH-ferricyanide reductase, NADPH-ferricyanide reductase and peroxidase), citrate synthase and alkaline phosphatase in various tissues (cerebrum. cerebellum, cardiac muscle, liver and kidney) was made ultracytochemically between normal male adult rats kept in the ordinary light environment and those kept in the complete dark. It was found that all oxidoreductases examined except peroxidase revealed the higher activity in rats kept in the complete dark in terms of the number of the enzymatically positive mitochondria and the activity of each mitochondrion. This tendency was most evident in the case of the NADPH-ferricyanide reductase; the NADPH-ferricyanide reductase activity was hardly detectable in tissues of rats kept in the ordinary light environment, but it could easily be detected in tissues of rats kept in the complete dark. This increase of the enzymatic activity (diurnal change) was not manifested in rats kept in the dark for 1hr, but began to be manifested 3 to 5 hrs following the onset of keeping rats in the complete dark, when examined with the NADPH-ferricyanide reductase activity. Puromycin (2.5mg/100g of body weight) and actinomycin D (0.06mg/100g of body weight) did not affect the occurrence of this diurnal enzyme change, suggesting that the diurnal enzyme change is the increase in the activity of mitochondrial oxidoreductases rather than the induction of enzymes (new synthesis of enzyme proteins). The diurnal change was not found with alkaline phosphatase and peroxidase, but it was of interest to note that the activity of citrate synthase seemed to be slightly lower in rats kept in the dark for 24hrs.