Reduction of glycemic potentiation. Sensitive indicator of beta-cell loss in partially pancreatectomized dogs.
To determine which test of islet function is the most sensitive indicator of subclinical beta-cell loss, we studied six conscious dogs before and 1 and 6 wk after removal of the splenic and uncinate lobes [64 +/- 2% pancreatectomy (PX)]. To assess hyperglycemic potentiation, acute insulin secretory responses (AIR) to 5 g i.v. arginine were measured at the fasting plasma glucose (FPG) level after PG was clamped at approximately 250 mg/dl and after PG was clamped at a maximally potentiating level of 550-650 mg/dl. FPG levels were unaffected by PX (112 +/- 4 mg/dl pre-PX vs. 115 +/- 5 mg/dl 6 wk after PX, P NS). Similarly, basal insulin levels remained constant after PX (11 +/- 2 microU/ml pre-PX vs. 11 +/- 1 microU/ml 6 wk after PX, P NS). The AIR to 300 mg/kg i.v. glucose decreased slightly from 42 +/- 9 microU/ml pre-PX to 32 +/- 5 microU/ml 6 wk after PX (P NS), and thus the beta-cell loss was underestimated. In contrast, insulin responses to arginine declined markedly after PX. The AIR to arginine obtained at FPG levels declined from 23 +/- 3 microU/ml pre-PX to 13 +/- 2 microU/ml 6 wk after PX (P = .04). The AIR to arginine obtained at PG levels of approximately 250 mg/dl declined even more, from a pre-PX value of 56 +/- 7 microU/ml to 21 +/- 4 microU/ml 6 wk after PX (P = .02).(ABSTRACT TRUNCATED AT 250 WORDS)
Ward
W K
WK
Department of Medicine, University of Washington, Seattle.
Wallum
B J
BJ
Beard
J C
JC
Taborsky
G J
GJ
Porte
D
D
D000818:Animals; D001120:Arginine; D001786:Blood Glucose / Q000378:metabolism*; D002395:Catecholamines / Q000097:blood; D004285:Dogs; D005934:Glucagon / Q000378:metabolism; D005947:Glucose; D007328:Insulin / Q000097:blood / Q000378:metabolism / Q000502:physiology; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D010180:Pancreatectomy
D001786:Blood Glucose; D002395:Catecholamines; D007328:Insulin; D005934:Glucagon; D001120:Arginine; D005947:Glucose