Distribution of Acid Phosphatase in Other Tissues

Intracellular Distribution of Acid Phosphatase in Other Tissues 

Most of our knowledge of lysosomes arises from studies of these particles in rat liver. These studies have also supplied considerable evidence that, by virtue of its more than a dozen hydrolytic enzymes, the lysosome can play a role in digesting material foreign to the cell, its own cell, or that its enzymes may be discharged outside the cell to produce lytic effects. It is also possible, as has been shown for rat liver (Rl), that lysosomes may be heterogeneous in terms of their enzyme contents. We shall now examine the extent to which acid phosphatase is distributed intracellularly in tissues other than the liver and in species other than the rat. 

With this understanding in mind, the values of Shibko et al. (S17) may be presented. For livers of various species the total acid phosphatase activity, expressed as nanomoles of substrate hydrolyzed per milligram 

The centrifugal method of separation employed by Van Lancker and Holtzer (V2) was among the earlier ones in the field, and there was probably considerable cross contamination of the fractions. Nonetheless, the distribution seems more disperse than that obtained by de Duve et al. (DIO) for rat liver with a comparable method. For example, in the case of the mouse pancreas the small mitochondrial fractions, c, d, and e, obtained by centrifugation between 17 X 10 and 263 X 10 gr-min contained 27% of the acid phosphatase and the succeeding microsomal fractions, f and g, obtained by centrifugations between 263 X 10 g-min and 3170 X 10 g-min, contained 24% of the acid phosphatase (V2). For rat liver, comparable fractions, obtained by centrifugation between 33 X 10 to 250 X 10 g-min and 250 X 10 to 3000 X 10 g-min contained 41 and 20%, respectively (DIO). 

In man and in other mammalian species, the major mass of the prostate, usually consisting of the right and left lateral and the middle lobes, is composed of alveoli lined with columnar epithelium embedded in a thick fibromuscular stroma. These alveoli constantly secrete a fluid which is drained off by a system of branching ducts that empty into the floor and lateral surfaces of the posterior urethra. The normal secretion is dependent upon the degree of androgenic stimulation and amounts to about 0.5-2 ml per day. The prostatic secretion, which is characterized by very high acid phosphatase activity, is a milky fluid which contains citric acid, choline, cephalin, cholesterol, proteins, and electrolytes similar to those found in the plasma. 

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