Manganese action on pancreatic protein synthesis in normal and diabetic rats.
The effects of manganese on [3H]phenylalanine incorporation into protein were studied in pancreatic acini prepared from normal and streptozotocin-induced diabetic rats. In the absence of added Ca2+ manganese exerted a biphasic effect on [3H]phenylalanine incorporation in both groups of acini. Significant stimulation occurred at 3 X 10(-5) M manganese. At higher concentrations manganese inhibited incorporation. The magnitude of stimulation was similar in all acini, whereas the magnitude of inhibition was greater in acini from normal rats. Addition of Ca2+ to incubation media abolished the stimulatory effect of manganese in normal rat acini and greatly enhanced it in diabetic rat acini, significant stimulation now occurring at 10(-5) M manganese. The magnitude of inhibition was again greater in acini from normal rats. Insulin in vivo partially reversed the diabetes-induced alterations in acinar cell responsiveness to manganese. The present findings suggest that streptozotocin-induced diabetes is associated with postreceptor alterations in the pancreatic acinar cells.
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D011506:Proteins / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains
D011506:Proteins; D008345:Manganese; D010649:Phenylalanine