1. The effect of insulin-induced hypoglycaemia on gastro-jejunal motility was studied in five, healthy, male subjects using tethered, pressure sensitive, radiotelemetry capsules.
2. Thirty minutes after the intravenous injection of soluble insulin (0.15 unit/kg body weight), a significant reduction in blood glucose concentration (control: 5.26 ± 0.19 sem mmol/l; insulin: 1.48 ± 0.44 mmol/l; P < 0.001) was associated with a rise in heart rate (mean peak rise 29 ± 8 beats/min, P < 0.05), systolic arterial blood pressure (mean peak rise 28 ± 4 mmHg, P < 0.01) and plasma pancreatic polypeptide concentration (control: 20 ± 7 pmol/l; insulin: 287 ± 66 pmol/l; P < 0.01). These events coincided with a short period of jejunal motor activity, which was not associated with gastric motor activity nor with raised plasma motilin concentrations.
3. During the control study, there were no changes in blood glucose concentration, heart rate, arterial blood pressure or plasma pancreatic polypeptide concentrations, and there was no jejunal motor activity.
4. The interval between successive gastric migrating motor complexes (MMC) was not significantly different in the insulin and control studies (control: median interval 110 min, range 108–148 min; insulin: median interval 124 min, range 115–125 min), suggesting that the fasting gastro-jejunal MMC and jejunal motor activity arose independently.
5. Insulin-induced hypoglycaemia is accompanied by jejunal motor activity, which may underlie the abdominal symptoms associated with hypoglycaemia.