Cholinergic effect of 2-deoxy-D-glucose on plasma glucagon levels in conscious rats.

The present study was conducted to investigate how the in vivo glucagon secretory response to 2-deoxy-D-glucose relates to control of nervous system. Plasma glucagon levels in the rat were significantly elevated by 2-deoxy-D-glucose administration (40 mg/100 g body weight). That response was suppressed by hexamethonium, a nicotinic ganglionic blocker. By contrast, treatment with atropine (5 mg/100 g body weight), a muscarinic antagonist, had no effect on glucagon secretion due to the same dose of the deoxysugar, whereas the drug totally inhibited the response to a lower concentration of the deoxysugar. Administration of 2-deoxy-D-glucose significantly elevated plasma epinephrine levels, and it was suppressed by hexamethonium. Plasma insulin levels were not so changed despite hyperglycaemia. In conclusion, the present study suggests that 2-deoxy-D-glucose may act on cholinergic nerve system to stimulate the release of glucagon and epinephrine.

Elevation of plasma triglyceride levels due to 2-deoxy-D-glucose in conscious rats.

Hypertriglyceridemia due to 2-deoxy-D-glucose administration was observed in conscious rats. Plasma triglyceride levels were elevated dose-dependently 2 or 3 hrs after administration of 2-deoxy-D-glucose (5-40 mg/100 g body weight). Prior to the rises in triglyceride, plasma epinephrine levels were elevated rapidly, whereas plasma insulin was not increased depspite continuous hyperglycemia. Elevation of plasma triglyceride was suppressed by addition of phentolamine, whereby insulin release was remarkably enhanced. Plasma lipoprotein lipase release by heparin infusion was significantly suppressed 2 hr after 2-deoxy-D-glucose administration. In conclusion, it is suggested that the hypertriglyceridemic effect of 2-deoxy-D-glucose may be mediated by decreased clearance of endogeneous lipoprotein particles (mostly chylomicrons) attributable to a lowered lipoprotein lipase activity.

Maintenance of neonatal endocrine cells of the rat. I. Effects of 2-deoxyglucose and 2-deoxy-2-fluoroglucose.

Pancreatic endocrine cells of the neonatal rat cultured in medium with 5.5 mM glucose for 7 days showed no response to glucose. By contrast, the supplementation of the medium with 1.0 mM 2-deoxyglucose or with 0.1-5.0 mM 2-deoxy-2-fluoroglucose maintained the capacity of glucose-induced insulin release and biosynthesis, and the recovery of insulin in cells at day 7 at levels significantly higher than in basal medium; the highest responses were recorded for 1.0 mM deoxysugars. Moreover, the addition of 1.0 mM deoxysugars caused a selective deletion of fibroblasts and yielded monolayers mostly consisted of endocrine cells at the end of the culture study period. In these monolayer cells, the stimulating level of c-AMP release was significantly higher than the basal. On the other hand, the in vitro function of A cells in culture was also better preserved in media with 1.0 mM deoxysugars.

Effect of D-glucosamine on the functional maturation of cultured B cells of the neonatal rat.

The present study demonstrates the effect of glucosamine on the functional maturation of cultured B cells of the neonatal rat. When B cells had been maintained at a physiological concentration (5.5 mM) of glucose for 7 days, a drop in the stimulatory effect of 16.7 mM glucose on insulin release and biosynthesis was observed together with a reduced insulin content. By contrast, the sensitivity of glucose-induced insulin release was increased after one week of culture with 5.5 mM glucose and 5 mM glucosamine. And both the insulin content and glucose-induced insulin biosynthesis also remained at the same level as observed at the first day of culture with 5.5 mM glucose alone. In summary, it was suggested that glucosamine-supplemented culture may result in the transition of B cells of neonatal rat from a poor glucose sensitivity to adult-type response of insulin release.