Age-related changes in glycerolipid formation in lean and obese Zucker rats.

Age-related changes in hepatic and adipose glycerolipid formation have been described in Zucker rats. Glycerolipid formation was measured in vitro in the presence of [14C]glycerol-3-phosphate, palmitate, ATP, CoA, and Mg2+ by using liver and adipose tissue homogenates derived from various age groups of animals. Hepatic glycerolipid formation increased after birth to reach a peak value at 1 day of age. This period was followed by a decline in the rates of glycerolipid formation. Hepatic glycerolipid formation increased again at the time of weaning and continued to rise up to 32 days in lean rats and 42-44 days in obese rats. Obesity in rats was recognizable at the age of 32 days and was associated with increased rates of glycerolipid formation in both liver and adipose tissue. As far as the changes in hepatic glycerolipid formation and triglyceride accumulation are concerned, obese rats showed more resemblance to 1-day-old rats than to lean animals of similar age groups. Glycerolipid formation decreased in liver and increased in adipose tissue with age in both lean and obese rats. These studies suggest that hepatic and adipose tissue glycerolipid formation is significantly influenced by age and obesity in Zucker rats.