Influence of Hypothalamus on Glucose Utilization by Adipose Tissue of Normal Rats

Summary

This study was designed to investigate whether Ventro-Medial and Ventro-Lateral Hypothalamus exert a direct effect upon the glucose uptake by rat adipose tissue.

VMH, VLH and pieces of cortex as controls were removed from normal rats fasted for either 6 h (Exp. A), or 14 h (Exp. B), or made hyperglycemic by i.p. injection of glucose (Exp. C). The tissue pieces were then incubated for 30 minutes at 37°C in Gey-Gey buffer. Aliquots of these incubates were then added to flasks containing epididimal fat pads of rats fasted 6 h, U-¹⁴C-glucose and unlabeled glucose to a final concentration of 1 mg/ml and incubated for additional 3 h at 37°C.

In exp. A the glucose utilization by adipose tissue was not affected by the addition of either VMH or VLH incubation media, when compared to controls. In exp. B a significant increase of glucose utilization was elicited by the addition of VLH incubates, while in exp. C the addition of VLH incubation media produced a significant decrease of glucose uptake by adipose tissue. The addition of VMH incubates had no significant effect in any of these experimental conditions.

These results support the hypothesis that a hypothalamic factor may have a direct action upon glucose utilization by the adipose tissue, independently of the control exerted by hypothalamus on insulin and glucagon release.

Key-Words

Ventro-Lateral Hypothalamus (VLH) - Ventro-medial Hypothalamus (VMH) - Adipose Tissue - Glucose Uptake - Incubation Media