Age-dependent regulation of lipogenesis in human and rat adipocytes.
The regulation of adipocyte metabolism is of importance for adipose tissue growth and therefore also for the development of obesity. This study was designed to investigate the regulation of basal and insulin-induced lipogenesis, glucose transport, and glucose transporter protein expression in human and rat adipocytes from different age groups. The study included 21 infants, 21 children, nine adults, and 80 male weaned and 20 male adult Fischer rats. The lipogenesis experiments were performed under conditions at which glucose transport is rate limiting. Basal lipogenesis was approximately three times higher in infants and children than in adults, whereas insulin-induced lipogenesis was two times higher in infants than in children and adults. In rats, basal lipogenesis, insulin-induced lipogenesis, and insulin sensitivity were two times higher in weaned than in adult animals. Moreover, basal and insulin-induced glucose transport were two times higher in weaned than in adult rats. No differences were detected in GLUT1 or GLUT4 content between any of the age groups in human or in rat adipocytes. In conclusion, basal and insulin-stimulated lipogenesis are increased in adipocytes early in life. This may promote adipose tissue growth in early age. The data indicate that age-dependent variation in basal and insulin-stimulated lipogenesis is differently regulated.
Kamel
Ashraf F
AF
Department of Pediatrics, National Childhood Obesity Centre, Children's Hospital, Huddinge University Hospital, Karolinska Institute, S-141 86 Huddinge, Sweden.
Norgren
Svante
S
Strigård
Karin
K
Thörne
Anders
A
Fakhrai-Rad
Hossein
H
Galli
Joakim
J
Marcus
Claude
C
D017667:Adipocytes / Q000378:metabolism*; D000328:Adult; D000367:Age Factors; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D008055:Lipids / Q000096:biosynthesis*; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000032:analysis; D009124:Muscle Proteins; D051381:Rats
D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D008055:Lipids; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495677:SLC2A1 protein, human; C495692:SLC2A4 protein, human; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat; D005947:Glucose