Comparison of the modifying effects of somatostatin and propranolol on morphine-induced changes in glucose, glucagon and insulin levels in fed rats.
Twenty-eight rats in four different groups were used. Catheters were implanted in the carotid artery and jugular vein one week before the experiments were performed. The rats were trained to the experimental situation daily, and allowed food and water ad libitum. One group of rats was used to establish control values; a second was injected with morphine (10 mg/ml, 1 ml/kg); a third group got morphine injection (10 mg/ml, 1 ml/kg) combined with somatostatin infusion (0.01 mg/ml, 1 ml/h); and the fourth group was injected with morphine (10 mg/ml, 1 ml/kg) combined with propranolol (0.4 ml, 1 mg/ml). Blood samples for venous glucose and arterial insulin and glucagon were drawn 15 min after start of stimulation. Glucose, insulin and glucagon levels were significantly higher in morphine treated than in control rats. When morphine was combined with somatostatin, the increase in glucose, insulin and glucagon was significantly reduced. However, after the morphine and propranolol stimulation the increase in glucose and glucagon was significantly reduced, whereas the insulin levels were as high as when morphine was given alone. The combined reduction of both glucagon and glucose after somatostatin or propranolol treatment in morphine exposed rats, points to glucagon as a potential link between opioid stimulation and hyperglycemia. Beta-receptor stimulation seems to contribute to the glucagon but not to the insulin release after morphine.
Johansen
O
O
Department of Orthopaedics, Tromsø University Hospital.
Jorde
R
R
Tønnesen
T
T
Burhol
P G
PG
Tveita
T
T
Reikerås
O
O
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D004357:Drug Synergism; D005502:Food; D005934:Glucagon / Q000097:blood*; D007328:Insulin / Q000097:blood*; D009020:Morphine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D013004:Somatostatin; D009020:Morphine; D005934:Glucagon; D011433:Propranolol