The effects of corticosterone, cold exposure and overfeeding with sucrose on brown adipose tissue of obese Zucker rats (fa/fa)

Abstract

1. GDP binding to brown-adipose-tissue mitochondria was decreased in obese Zucker rats. 2. Adrenalectomy restored both GDP binding and serum triiodothyronine of obese rats to values observed in lean rats. 3. The effects of adrenalectomy on GDP binding and serum tri-iodothyronine were reversed by corticosterone. 4. Decreasing food intake had no effect on brown-adipose-tissue GDP binding in obese rats. 5. Young (5-week-old) obese rats showed a normal increase in brown-adipose-tissue mitochondrial GDP binding after housing at 4°C for 7 days, but this response was attenuated in 10-week-old obese rats. 6. Overfeeding with sucrose increased brown-adipose-tissue thermogeneis in lean, but not in obese, rats. 7. After adrenalectomy, overfeeding with sucrose enhanced brown-adipose-tissue mitochondrial GDP binding in obese rats.