Influence of norepinephrine, growth hormone and fasting on FFA mobilization and glucose metabolism in lean and obese subjects

Abstract

Summary. The influence of norepinephrine (NE), human growth hormone (I-IGH) and fasting on FFA mobilization and carbohydrate metabolism has been studied in 47 obese females and 72 nonobese control subjects (35 females and 37 males). --Weight-related doses of l~E infused for 2 h (0.1 y/kg/min) induced a much greater rise in plasma FFA and blood glucose concentrations in obese than in normal subjects. With a fixed dose (10 y/rain for 2 h), FFA response was still significantly higher in the overweight than in the lean subjects, while glucose reponses were similar in both groups. Among the control subjects, males and females behaved simflarily. --The plasma FFA rise observed in the 4 h following the g.v. injection of HGI-I (10 rag) was not statistically different in obese females, normal males and normal females. --These results suggest that human obese adipose tissue has no impaired sensitivity toward the lipolytic action of NE and HGH. --During fasting, obese, when compared with normal subjects, showed a smaller increase in plasma FFA level together with a smaller decrease in glucose flux. The possible relationship between these 2 anomalies is discussed, considering that glucose deficiency has a major role in regulating FFA mobilization during fasting. Influence de la noradrdnalinc, de ~'hormone de troissauce et du ~e~ne sur la mobitisation des F~FA et sur le m~tabolisme glucidique chez des 8ujets ob~ses et normaux

Ventromedial Hypothalamic Lesions and the Mobilization of Fatty Acids

“…Fastiing is known to increase the conicenltrationi of' FFA (29)(30)(31)(32), and this is conisistent with our findings. In addition to raising FFA, fastinig also increased glycerol and reduced both insulin and glucose in all groups, but the effects were greater in the shamii-operated ainimals than in those with VMH lesions.…”

Influence of body fat distribution on free fatty acid metabolism in obesity.

“…Increased FFA availability is necessary for optimal metabolic function in situations such as fasting (39) and exercise (40). Intravenous epinephrine infusions have been used to test for defects in the ability of obese persons to enhance lipolysis (6)(7)(8), however, conflicting findings have been reported (6)(7)(8). In this study, the lipolytic response to epinephrine was reduced in upper body obese women compared with lower body obese and nonobese women.…”

“…Free fatty acid metabolism in obesity has, therefore, been the subject of many studies over the last thirty years. Unfortunately, conflicting conclusions regarding several aspects of FFA metabolism have appeared, including the antilipolytic effectiveness ofinsulin in obesity (1,2), the relationship of FFA release to the amount of body fat (3)(4)(5), and the lipolytic responsiveness of obese individuals to catecholamines (6)(7)(8). These potential differences in FFA metabolism between lean and obese humans may be of considerable importance in that they reflect either abnormalities of adipose tissue or of the body's ability to hormonally regulate adipose tissue lipolysis.…”

An abnormality of adrenaline, phentolamine stimulated lipolysis in adipose tissue from obese, maturity-onset diabetics

“…The combined effects of these agents in rive does not appear to have been investigated. Adrenaline infusion has been variously reported to produce a raised, normal [29] or diminished [30], increase in plasma FFA in obese individuals. However the effects of adrenaline in vivo are more complex than those in vitro on account of effects of the hormone on the secretion of other hormones with an influence on lipolysis, particularly insulin [31].…”