Semester

Summer

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

School of Medicine

Department

Exercise Physiology

Committee Chair

Mark Olfert

Committee Co-Chair

Randall Bryner

Committee Member

Mark Olfert

Committee Member

Linda Vona-Davis

Abstract

Reducing vascular endothelial growth factor (VEGF) in adipose tissue alters adipose vascularity and metabolic homeostasis. We hypothesized that this would also affect metabolic responses during exercise-induced stress, and that adipocyte-specific VEGF deficient (adipoVEGF-/-) mice would have impaired endurance capacity. Endurance exercise capacity in adipoVEGF-/- (n=10) and littermate control (n=11) mice was evaluated every 4 weeks between 6 & 24 weeks of age using a submaximal endurance run to exhaustion at 20 m/min, 10-degree incline. Maximal running speed, using incremental increases in speed at 30-second intervals, was tested at 25 weeks of age. Beginning at 6 weeks, and continuing with all time points, endurance run time to exhaustion was 30% lower in adipoVEGF-/- compared to controls (p<0.001). The age-associated rate of decline in endurance capacity was similar in adipoVEGF-/- vs. control mice and there was no difference in maximal running speed between the groups. Following 1 hour of running at 50% maximum running speed, adipoVEGF-/- mice displayed decreased circulating insulin, (p<0.001), glycerol (p<0.05), and a tendency for decreased glucose (p=0.06) compared to controls. These data suggest that deficits in adipose tissue vasculature are mediated by adipose VEGF and that deficiency of VEGF blunts the availability of lipid-derived substrates during endurance exercise and affects insulin secretion and glucose metabolism.

Share

COinS