Nutrition-aging influence of catecholamine-promoted lipolysis

Abstract

Male SPF Fischer 344 rats were fed ad lib. (group A) or 60% ad lib. intake (group R) from 6 wk of age. The group R rats had a markedly increased median length of life. Starting at 6 mo of age, rats were periodically killed and free adipocytes prepared from the epididymal and perirenal depots. The free adipocytes were used for the in vitro study of the effects of age on the promotion of lipolysis by catecholamines. At 6 mo of age, the response of the adipocytes from group A and group R rats was similar when the data are expressed as μmole glycerol released/10 6 adipocytes. With increasing age, however, this lipolytic response to catecholamines of group A rats markedly declined. The catecholamine-stimulated lipolysis/10 6 adipocytes from group R rats changed little between 6 and 18 mo of age, and the decline noted after 18 mo of age was less marked than that occurring in adipocytes from group A rats. The data based on rates of lipolysis/10 6 adipocytes indicate that it is the lifelong nutritional history of a rat population that determines the age-related changes in responsiveness of adipocytes to catecholamines. However, if the data are expressed per sq mm of adipocyte surface, a somewhat different picture emerges. These data are presented and their relevance is discussed.