Influence of short-term lithium carbonate administration on stimulated insulin secretion in normal man

We have studied the effects of short-term treatment with lithium carbonate (900-1,200 mg/day for 4 days) on insulin secretion and blood glucose levels of 28 healthy volunteers (8 females and 20 males, aged 23-29 years) who underwent the following stimulations: two intravenous glucose loads of 25 and 5 g (IVGTT25; IVGTT5); arginine infusion (25 g over 30 min); tolbutamide test (0.25 g i.v.). Seven subjects for each group were tested. A placebo treatment was also performed. Short-term lithium treatment significantly reduced the insulin response to IVGTT25, arginine and tolbutamide. No differences were observed in blood glucose levels during all stimuli. Serum electrolyte levels and thyroid function were not affected by the treatment. In conclusion, these findings suggest, in healthy subjects, a good peripheral glucose utilization after brief-term lithium administration, in spite of impaired insulin response to various stimuli.