Streptozotocin-induced diabetes rsulted in a decrease in the cathepsin D activity (free and total) in rat liver, kidney, brain and heart with a concomitant increase in tissue protein content and amino acids pool size. Treatment with insulin brought about the restoration of the cathepsin D activity to normal or greater than normal levels; tissue protein content and amino acids pool size also returned to normal values.

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Insulin-dependent changes in lysosomal cathepsin D activity in rat liver, kidney, brain and heart

The effect of thyroidectomy and subsequent treatment with tri-iodothyronine (T3), as well as that of thyrotoxicosis, was examined on cathepsin D activity in the rat liver, kidney and brain. Thyrotoxicosis resulted in a generalized increase in the enzyme activity in the 3 tissues; the effect of other thyroidal states was diverse and tissue-specific.

Thyroid hormones and cathepsin D activity in the rat liver, kidney and brain.

Some of the biochemical indices relevant to the "free radical theory" of aging have been assessed in mice subjected to chronic low-dose whole-body irradiation Radiation exposure results in enhanced accumulation of the lipofuscins in brain, heart, and intestine In these animals, the degree of lipoperoxidation in liver was greatly increased, as were the free activities of acid phosphatase and cathespin, indicating damage to lysosomal membranes The activity of SOD in brain and liver 20,000g post-mitochondrial supernatants was lower in the irradiated mice All these changes arising from chronic whole-body irradiation are similar to those observed during aging and are effectively prevented by dietary supplementation with BHT These observations lend considerable support to the "free radical theory" of aging

Effects of chronic irradiation on age-related biochemical changes in mice.

Effects of total body γ-irradiation with sub-lethal dose (300 rad) on three lysosomal enzymes namely acid phosphatase, ribonuclease-II and deoxyribonuclease-II have been studied in pigeons. Liver, kidney and spleen were the tissues studied at different intervals like 1-h., 24-h, 48-h, and 72-h of irradiation. The specific activities (‘crude’ fraction) of acid phosphatase and ribonuclease-II increased significantly in spleen and liver at 48-h of irradiation. The activity of deoxyribonuclease-II in liver and spleen was increased only at 72-h post-irradiation. On the other hand, the total activities of three lysosomal enzymes did not show remarkable change throughout 72-h of irradiation.

Effects of sub-lethal dose of gamma-irradiation on lysosomal enzymes in tissue of pigeon.

A polar radiation degradation product (RDP) isolated from β-carotene exposed to gamma rays (1 Mrad) exhibited labilizing action on rat liver lysosomes. This was observed to be concentration dependent as revealed by the proportionate increase in the free activities of acid ribonuclease and aryl sulphatase. When polar products obtained from irradiated vitamin A and β-carotene were compared with respect to their lysosome disrupting properties, it was found that the products of vitamin A accomplished the release of enzymes more readily than the compound derived from β-carotene. The observed differences in the extent of lysosome labilization, Rf value and absorption maximum suggested that the RDP derived from β-carotene is different from its vitamin A counterparts.

Bhushan B

Papers

Influence of vitamin A acetate, alcohol and their radiolytic products on the in vitro labilization of lysosomes and tissue autolysis.

Alterations in liver lysosomes induced by whole-body x-irradiation of rats.

ビタミンA酢酸エステル,ビタミンAアルコール,これらの照射分解産物のin vitroでのリソゾームの不活性化への影響,および組織の自己分解