Glucoregulation during rest and exercise in depancreatized dogs: role of the acute presence of insulin.
To determine the effects of the presence of insulin in poorly controlled diabetes, depancreatized (PX) dogs (n = 5) were studied during rest and 150 min of exercise in paired experiments in which saline alone was infused (IDEF) and in which insulin was replaced intraportally (200 microU.kg-1.min-1) with glucose clamped at the levels in IDEF (IR+G). PX dogs (n = 4) were also studied with insulin, but glucose was allowed to fall (IR). Insulin was not detectable, 6 +/- 1 and 6 +/- 2 microU/ml in IDEF, IR+G, and IR. Plasma glucose was 470 +/- 47, 480 +/- 48, and 372 +/- 35 mg/dl at rest in IDEF, IR+G, and IR, respectively. Levels were unchanged with exercise in IDEF and IR+G, but fell by 139 +/- 13 mg/dl in IR. Basal glucose rate of appearance (Ra) was 7.0 +/- 0.9, 1.3 +/- 1.1, and 6.0 +/- 0.7 mg.kg-1.min-1 in IDEF, IR+G, and IR, respectively. Exercise elicited a rise in Ra in only IDEF. The rises in Rd and metabolic clearance rate in IDEF were reduced (delta 2.6 +/- 0.7 and delta 0.8 +/- 0.3 ml.kg-1.min-1 at 150 min) compared with IR+G (delta 5.3 +/- 1.9 and delta 1.7 +/- 0.2 ml.kg-1.min-1 at 150 min) and IR (delta 3.7 +/- 1.2 and delta 2.4 +/- 0.8 ml.kg-1.min-1). The insulin sensitivity of glucose utilization (Rd) was elevated by approximately 75% at 150 min. Basal glycerol was similar in IDEF and IR but was reduced by approximately 70% in IR+G. Glycerol rose similarly with exercise in IDEF and IR.(ABSTRACT TRUNCATED AT 250 WORDS)
Wasserman
D H
DH
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Bupp
J L
JL
Johnson
J L
JL
Bracy
D
D
Lacy
D B
DB
D000818:Animals; D001158:Arteries; D001786:Blood Glucose / Q000032:analysis; D002395:Catecholamines / Q000097:blood; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000097:blood; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007700:Kinetics; D010180:Pancreatectomy; D005082:Physical Exertion; D012146:Rest
D001786:Blood Glucose; D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D005934:Glucagon; D005947:Glucose; D005990:Glycerol; D006854:Hydrocortisone