American Journal of Clinical Nutrition, Vol 8, 719-727, Copyright © 1960 by The American Society for Clinical Nutrition, Inc.

The Obese Hyperglycemic Syndrome in Mice

Metabolism of Isolated Adipose Tissue In Vitro

¹ From the Department of Medicine, Harvard Medical School; the Baker Clinic Research Laboratory, New England Deaconess Hospital; and the Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts

The metabolic activity of epididymal adipose tissue from obese hyperglycemic mice was compared with that of adipose tissue from their non-obese siblings. Three main differences were noted. (1) Adipose tissue from obese animals contained more nitrogen, suggesting an increased cytoplasmic mass. (2) Glucose utilization and metabolism by adipose tissue from obese hyperglycemic mice were persistently less than that of control tissues, when the comparision was carried out on the basis of nitrogen content or wet weight. This was especially true for tissue fromrm the most obese mice. (3) Incorporation of acetate carbon into fatty acids was five to ten times greater than normal in tissue from obese animals, whereas acetate oxidation to CO₂ was essentially the same as in tissue from non-obese control animals.

Tissues from obese and non-obese animals did not differ qualitatively in their response to insulin or growth hormone, and studies with specifically labeled glucose did not suggest the presence of abnormal pathways of glucose metabolism in the obese tissue.

These findings suggest that adipose tissue from obese hyperglycemic mice metabolizes an excessive amount of available substrate carbon to fatty acids, and that fatty acid synthesis in this tissue is less dependent upon the simultaneous occurrence of accelerated glucose metabolism than is true for normal adipose tissue from mice or rats.