Distribution of Hydrolases among Anterior Pituitary Cell Fractions (Anterior Pituitary Hydrolases)

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Abstract
Anterior pituitary lobes from freshly slaughtered pigs were homogenized in 0.25 M sucrose and separated into subcellu-lar fractions by differential centrifugation. The specific activity of succinic dehydrogenase was highest in the "light mitochondrial" fraction, that for alkaline phosphatase was highest in the microsomes, and acid phosphatase, acid ribonuclease, and acid proteinase showed greatest activity in the "heavy mitochondrial" fraction. Succinic dehydrogenase was almost exclusively localized in mitochondria. Alkaline phosphatase was concentrated in the microsomes, but the acid hydrolases were distributed over several fractions suggesting their association with a particle type possessing considerable variation in size. The acid hydrolases described above have been previously identified with the lysosomal elements in liver fractions. On the basis of the present findings, it appears that hydrolytic enzymes are segregated in distinct particles in other tissues besides liver.