Exercise training increases the number of glucose transporters in rat adipose cells.
We studied the mechanism for the increase in glucose transport activity that occurs in adipose cells of exercise-trained rats. Glucose transport activity, glucose metabolism, and the subcellular distribution of glucose transporters were measured in adipose cells from rats raised in wheel cages for 6 wk (mean total exercise 350 km/rat), age-matched sedentary controls, and young sedentary controls matched for adipose cell size. Basal rates of glucose transport and metabolism were greater in cells from exercise-trained rats compared with young controls, and insulin-stimulated rates were greater in the exercise-trained rats compared with both age-matched and young controls. The numbers of plasma membrane glucose transporters were not different among groups in the basal state; however, with insulin stimulation, cells from exercise-trained animals had significantly more plasma membrane transporters than young controls or age-matched controls. Exercise-trained rats also had more low-density microsomal transporters than control rats in the basal state. When the total number of glucose transporters/cell was calculated, the exercise-trained rats had 42% more transporters than did either control group. These studies demonstrate that the increased glucose transport and metabolism observed in insulin-stimulated adipose cells from exercise-trained rats is due, primarily, to an increase in the number of plasma membrane glucose transporters translocated from an enlarged intracellular pool.
Hirshman
M F
MF
Department of Medicine, University of Vermont College of Medicine, Burlington 05405.
Wardzala
L J
LJ
Goodyear
L J
LJ
Fuller
S P
SP
Horton
E D
ED
Horton
E S
ES
D000273:Adipose Tissue / Q000378:metabolism* / Q000502:physiology; D000375:Aging; D000818:Animals; D001835:Body Weight; D005247:Feeding Behavior; D005260:Female; D005947:Glucose / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009929:Organ Size; D010805:Physical Conditioning, Animal; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013347:Subcellular Fractions / Q000378:metabolism; D014280:Triglycerides / Q000096:biosynthesis
D009004:Monosaccharide Transport Proteins; D011506:Proteins; D014280:Triglycerides; D005947:Glucose