Hyperglucagonemia after removal of lower bowel in rats

Abstract

Surgical removal of the jejunum, ileum, and colon from rats (LBX) results in greatly elevated levels of plasma immunoreactive glucagon (pIRG) 24 h after surgery (0.98 +/- 0.07 ng/ml, n = 51 vs. 0.20 +/- 0.02 ng/ml, n = 34 in sham-operated controls). Such elevations in pIRG were not noted after gut transection or the removal of ileum, jejunum, or colon alone, ileum plus jejunum, or stomach plus duodenum. Coupled with the failure of adrenal demedullation, adrenalectomy or ganglionic blockade to lower pIRG in LBX animals, these findings suggest that surgical stress alone is an unlikely cause for LBX-induced hyperglucagonemia. It was also shown that alpha-cells in LBX animals retained their responsiveness to both the inhibitory effects of somatostatin and glucose infusion as well as the stimulatory effects of arginine infusion. Chromatography revealed a normal pattern of IRG in the plasma of LBX animals. It is postulated that LBX-induced hyperglucagonemia may result from the removal of an inhibitory factor present in the lower bowel.