Assessment by D-[H-3]mannoheptulose uptake of B-cell density in isolated pancreatic islets from Goto-Kakizaki rats

The uptake of D-[H-3]mannoheptulose by isolated pancreatic islets was recen tly proposed as a tool to assess the relative contribution of insulin-produ cing cells to the total mass of the islets. In the present study, the uptak e of the tritiated heptose over 60 min incubation at 37 degreesC was about 21% lower in islets from hereditarily diabetic rats (GK rats) than in islet s from control animals, this decrease being virtually identical to that doc umented previously by morphometric analysis of islets From the same type of rats. The intracellular (HOH)-H-3 space and extracellular [U-C-14]sucrose space were not significantly different in control and diabetic rats, at lea st when the comparison was restricted to animals of the same sex. There was a trend, however, towards a somewhat lower D-[5-H-3]-glucose intracellular distribution space in islets from GK rats, as compared to control animals. These findings provide further support to the validity of D-[H-3]mannohept ulose uptake as a tool to assess the density of insulin-producing cells in isolated islets.