Nutritional regulation of lipid metabolism in human adipose tissue

Abstract

Pfeiffer and colleagues years ago pointed out that different distributions and amounts of adipose tissue are associated with abnormalities of lipolysis and lipoprotein metabolism. Adipose tissue has several crucial roles including (i) mobilization from stores of fatty acids as an energy source, (ii) catabolism of lipoproteins such as very-low-density lipoprotein and (iii) synthesis and release of hormonal signals such as leptin and interleukin-6. These adipose tissue actions are crucially regulated by nutrition. The review considers the existence of metabolic pathways and modes of regulation within adipose tissue, and how such metabolic activity can be quantitated in humans. Nutrition can influence adipose tissue at several 'levels'. Firstly the level of obesity or malnutrition has important effects on many aspects of adipose tissue metabolism. Secondly short-term overfeeding, underfeeding and exercise have major impacts on adipose tissue behaviour. Lastly, specific nutrients are capable of regulating adipose tissue metabolism. Recently there have been considerable advances in understanding adipose tissue metabolism and in particular its regulation. This review discusses the behaviour of adipose tissue under various nutritional conditions. There is then a review of recent work examining the ways in which nutritional influences act via intra-cellular mechanisms, insulin and the sympathetic innervation of adipose tissue.

Tissue‐specific insulin signaling in the regulation of metabolism and aging

“…Insulin stimulates the uptake of glucose into adipocytes where it converts into lipids as a more efficient form of energy storage (adipogenesis) (45). Although adipose tissue accounts for a relatively small proportion (<10%) of the peripheral glucose utilization in response to insulin (46), it is not a passive repository for excess energy over the research in the past decades (47,48). Adipose tissue is the primary site for triacylglycerol storage (49), whereas the enhancement of glucose uptake increases triacylglycerol and FA synthesis in adipose tissues and might lead to obesity (50).…”

Genetic variation at the perilipin locus is associated with changes in serum free fatty acids and abdominal fat following mild weight loss

“…2 These effects cannot be entirely accounted by alterations in the action of the major lipolysis-regulating hormones, insulin and catecholamines. [2][3][4] Lipolysis occurs at the surface of the intracellular lipid droplet, where perilipins (PLINs), a family of phosphoproteins, are located. 5,6 Perilipins are found primarily in adipocytes and are required to activate lipolysis in stimulated states such as fasting or exercise, as well as to protect cellular triglycerides against hydrolysis in the basal state.…”

Effects of free fatty acids on ACTH and cortisol secretion in anorexia nervosa

“…Hyperactivity of CRH-and/or arginine vasopressin-secreting neurons as well as derangement in the hypothalamic and/or supra-hypothalamic mechanisms of negative glucocorticoid feedback action should be considered in this context (25,31,32). Lipid metabolism is altered in anorexia nervosa besides many other malnutrition disorders in which lipolysis is generally hyperactivated (20,40). Lipids, namely FFAs, are also known to play a major role also in controlling hypothalamus -pituitary function, which applies to somatotroph and gonadal axis control but also to the HPA axis (2, 3, 7, 41 -43).…”