Impact of complete isletectomy on plasma glucose in the southern hemisphere lamprey Geotria australis.

The adult southern hemisphere lamprey Geotria australis is the only known vertebrate in which it is possible to remove all of the pancreatic islet tissue without damaging other organs. In the 24 hr after isletectomy, the plasma glucose of adult G. australis rose sharply from 5.0 to 11.6 mmol.liter-1 and remained at a similar elevated level throughout the subsequent 5 days of the experiment. The marked hyperglycemia that follows complete isletectomy parallels the results obtained after removal of the majority of the islet tissue from northern hemisphere lampreys and after pancreatectomy in mammals, but contrasts with observations recorded for some other groups of vertebrates.