Effects of Prolonged Glucagon Administration in the Cat and Dog

Abstract

It has been postulated that glucagon, the hyperglycemic factor of the pancreatic a-cells, plays an important role in the pathogenesis of diabetes mellitus in man. 1 ' 2 This hypothesis suggests that an excessive secretion of glucagon in relation to insulin results in the diabetic state and is based on the finding of an increased a/P-cell ratio in the pancreatic islets of diabetic patients. One reason that the concept remains controversial is that efforts to induce permanent diabetes in the rat and the rabbit with glucagon have been unsuccessful. 3 ' 7 However, these experiments may be considered inconclusive for the following reasons: The rat and the rabbit are relatively insensitive to the hyperglycemic action of glucagon; 8 they also respond poorly to some diabetogenic agents; 9 and the experimental conditions used were perhaps not ideal. 610 The purpose of this study was to determine the effects of prolonged glucagon administration by various routes (including the portal vein) in the two species (cat and dog) most sensitive to glucagon 8 and to certain known diabetogenic agents. 9 METHODS Experiments were carried out in six cats and seven dogs, all adult animals. Five different glucagon preparations were used: ( i ) No. 225-20-255* (20 per cent puret); (2) No. 208-108B-234* (20 per cent pure);(3) No. 208-158B-197* (50 per cent pure); (4) crystalline glucagont (100 per cent pure); and (5) crystalline Zn-glucagon § (100 per cent pure). Only animals From the Radioisotope Service of the Veterans Administra-

Retrospective evaluation of the use of glucagon infusion as adjunctive therapy for hypoglycemia in dogs: 9 cases (2005–2014)

“…These animals experienced hyperglycemia for 1–3 hours following each single glucagon injection, and sustained hyperglycemia if receiving a CRI. All animals returned to baseline serum glucose concentrations following discontinuation of the glucagon, and there were no toxic effects, weight loss, or prolonged hyperglycemia noted with long‐term administration of glucagon . A more recent study comparing glucagon administration by subcutaneous and intravenous injection found significant increases in glucose concentrations 10, 20, and 30 minutes following administration .…”

“…discontinuation of the glucagon, and there were no toxic effects, weight loss, or prolonged hyperglycemia noted with long-term administration of glucagon. 13 A more recent study comparing glucagon administration by subcutaneous and intravenous injection found significant increases in glucose concentrations 10, 20, and 30 minutes following administration. 11 Significantly higher BG values were noted following intravenous administration compared to subcutaneous.…”

“…11,13 One study evaluated the effects of longer term administration of glucagon in healthy dogs and cats using several concentrations of glucagon, ranging from 0.4 to 18 mg/24 hours, with various routes of administration including intramuscular, intravascular, and intraperitoneal. 13 The duration of glucagon administration varied from 5 to 108 days. These animals experienced hyperglycemia for 1-3 hours following each single glucagon injection, and sustained hyperglycemia if receiving a CRI.…”

“…Although glucagon has been recommended for treatment of hypoglycemia in both people and animals, there is only 1 canine case report and limited studies in healthy small animals . One study evaluated the effects of longer term administration of glucagon in healthy dogs and cats using several concentrations of glucagon, ranging from 0.4 to 18 mg/24 hours, with various routes of administration including intramuscular, intravascular, and intraperitoneal . The duration of glucagon administration varied from 5 to 108 days.…”