Radiolabeled Colloid Uptake Distribution and Pulmonary Contents and Localization of Lysosomal Enzymes in Cholestatic Rats

Studies of the activity uptake of radiolabeled 99mTC2S7 colloid in different tissues showed a moderately increased uptake in the lung 1 week and a greatly increased uptake 3 weeks after permanent bile duct occlusion. Three weeks after bile duct occlusion the activity uptake was also slightly increased in the spleen and moderately reduced in the liver. In pulmonary tissue of cholestatic rats, the levels of alkaline and acid phosphatase, β-glucuronidase, and β-hexosaminidase were determined after 6 weeks. The pulmonary contents of β-glucuronidase was increased tenfold, and that of β-hexosaminidase was increased fourfold in cholestasis. Histochemical investigation showed that the lysosomal enzymes were located in the macrophages, which in cholestasis were abundant in alveolar walls and inside alveoli. Macrophages were also frequently seen to engorge pulmonary veins.