EFFECTS OF STREPTOZOTOCIN-INDUCED DIABETES, PHYSICAL-TRAINING AND THEIR COMBINATION ON COLLAGEN BIOSYNTHESIS IN RAT SKELETAL-MUSCLE

The effects of streptozotocin-induced diabetes, physical training and their combination on the activities of prolyl 4-hydroxylase (PH) and g alactosylhydroxylysyl glucosyltransferase (GGT), both marker enzymes o f collagen biosynthesis, and on the concentration of hydroxyproline (H yp) were studied in vastus lateralis, rectus femoris and gastrocnemius muscles in rats. The experimental period was 12-16 weeks. Diabetes ha d an overall decreasing effect on specific PH activity in all muscles studied, whereas specific GGT activity remained at control level. Tota l PH and GGT activities decreased in all three muscles in the diabetic animals (P < 0.001). Training caused an increase in PH and GGT activi ties in gastrocnemius in non-diabetic rats, whereas training in combin ation with diabetes did not change specific PH or GGT activity. Diabet es increased specific Hyp concentration in vastus lateralis and gastro cnemius in trained diabetic rats (P < 0.05), whereas training decrease d Hyp level significantly (P < 0.05) in vastus lateralis in non-diabet ic rats, but not in diabetic animals. The results suggest that in stre ptozotocin-induced diabetes the decrease in collagen synthesis rare ex ceeds the negative total protein balance in the muscle. Although physi cal training may have an increasing effect on muscular collagen synthe sis in non-diabetic rats, it is unable to prevent the decreasing effec t of diabetes on collagen synthesis.