Comparison of Lipogenic Responses to Dietary Glucose in Selected Mouse Adipose Tissues

Abstract

Rates of fatty acid synthesis from glucose-carbon (glucose-C) and all other 2-carbon (2-C) units were measured in three white adipose tissue sites of fasted and fed mice, which were given a test meal containing [U-¹⁴C]glucose. Total fatty acid synthesis was measured in all mice by intraperitoneal injection of ³H₂O. In fasted-refed mice the rates of lipogenesis from glucose-C and all 2-C sources were much faster in popliteal than in epididymal fat. Most of the newly synthesized fatty acids were derived from glucose-C. However, in fed-refed mice these differences between the sites were minimal, and all the absolute rates were much higher than those found in fasted-refed mice. This suggested that the adipose tissue in the three sites did not have different physiological roles. Variability in the actual rates of lipogenesis, from one experiment to another, in fasted-refed mice could be attributed to small differences in the periods of fasting, before the mice were given the test meal.

The Aging Fat Cell

“…The varied locations and cellular composition of adipose tissues make them respond differently to nutrient absorption, lipid mobilization, and hormonal or neural stimulation; these differences are noted as well in developmental and aging changes 49–56 . In humans, the anatomy of adipose tissue appears to be rather specific among nondomestic terrestrial mammals 57 ; superficial adipose tissue forms an almost continuous layer of variable thickness over much of the body.…”