QUANTITATIVE CRYOIMMUNOGOLD ELECTRON-MICROSCOPIC STUDIES ON INDUCTIONOF SERINE-PYRUVATE AMINOTRANSFERASE IN RAT-LIVER MITOCHONDRIA BY ADMINISTRATION OF GLUCAGON

Induction of mitochondrial serine : pyruvate aminotransferase (SPT) in rat liver by administration of glucagon was studied quantitatively by immunoblot analysis and cryoimmunogold electron microscopy. Immunoblo t analysis revealed that two daily injections of glucagon produced mar ked increase of SPT protein mass to a level as much as 18 times that o f the untreated rat. Cryoimmunogold electron microscopic analysis show ed that the labeling density of the mitochondria increased in a parall el manner. Thus the induction of SPT analyzed by two methods showed an excellent correlation with a relative correlation coefficient of 0.98 , indicating that the induction of SPT can be analyzed quantitatively by immunogold electron microscopy on cryoultrathin sections.