Microcalorimetric and biochemical investigations of thermogenesis and metabolic pathways in human white adipocytes.
OBJECTIVE
Validation of a novel culture technique for human white adipocytes, facilitating direct microcalorimetry and simultaneously performed biochemistry for 3 days.


METHODS
Subcutaneous adipocytes were cultured in a 3-dimensional matrix of agarose gel. Biochemical measures were obtained every 24 h, while thermogenesis was continuously monitored for 72 h. DNA content of the cultures served as reference.


METHODS
73 men and women undergoing uncomplicated surgery.


METHODS
Cell viability (LDH release), total cellular thermogenesis, oxygen consumption, glycolysis, lipolysis (basal, catecholamin-stimulated) triglyceride/free fatty acid substrate cycle, adenine nucleotides, insulin-induced thermogenesis.


RESULTS
LDH release was 0.4% of total LDH per hour. Cellular ATP, ADP and AMP (3.77, 0.39 and 0.06 nmol/microgramDNA, resp.) were constant. The rates of glucose consumption, lactate and pyruvate production and basal glycerol release (56.4, 43.1, 2.7 and 28.1 nmol/microgramDNA.h, resp.) were stable during 72 h. Isoprenaline (1 microM) enhanced lipolytic rate by the same extent at any time of the study (glycerol release 67.8 nmol/microgramDNA.h). FFA release (initially 26.0 nmol/ microgramDNA.h) declined during the experiment, due to an increase of reesterfication rate. Unstimulated heat production was 6.5 microW/microgramDNA, 68% of which were of oxidative origin. Insulin (0.1 microM) induced thermogenesis was 8.8 microW/ microgramDNA.


CONCLUSIONS
The results were in accordance with data from human white adipocytes in suspensions. However, in contrast to fat cell suspensions, gel cultured adipocytes were viable for 3 days without metabolic alterations.
Böttcher
H
H
Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, FRG.
Fürst
P
P
D017667:Adipocytes / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001833:Body Temperature Regulation; D002151:Calorimetry; D002470:Cell Survival; D002478:Cells, Cultured; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D019289:Pyruvic Acid / Q000378:metabolism
D005230:Fatty Acids, Nonesterified; D019344:Lactic Acid; D019289:Pyruvic Acid; D007770:L-Lactate Dehydrogenase; D005947:Glucose; D007545:Isoproterenol; D005990:Glycerol