Changes in metabolic rate and brown adipose tissue composition during nutritional rehabilitation of postnatally undernourished rats.
Rats previously undernourished (PU) during the first 3 postnatal weeks gained less weight than controls during the subsequent rehabilitation period, in spite of similar levels of food intake per body weight 0.75. Resting oxygen consumption (ml/min/kg0.75) was significantly elevated (15-22%) in the PU group after 36 days of age but this difference was almost completely abolished by beta-adrenergic blockade with propranolol. PU rats also showed a greater thermogenic activity after noradrenaline (25 micrograms/100 g b.wt.) than controls. The mass of brown adipose tissue (BAT, mg/100 g b.wt.) was reduced by undernutrition but during rehabilitation BAT increased in PU rats to a value greater than that of controls. These results indicate that the low weight gain of PU rats may result partly from a high metabolic rate due to sympathetic activation of BAT.
D002001:Adipose Tissue, Brown / Q000032:analysis*; D000375:Aging; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects; D001835:Body Weight; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D009748:Nutrition Disorders / Q000178:diet therapy / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains
D009638:Norepinephrine