Adipose tissue stores

When adipose tissue stores triglyceride arriving from the liver or intestine, glycolysis must also occur in the adipocyte. Which of the following products or intermediates of glycolysis is required for fat storage ... 

Adipose Tissue Stores and Supplies Fatty Acids... 

Caldironi, H.A. and Bazan, N.G. 1982. Effect of antioxidants on malonaldehyde production and fatty acid composition in pieces of bovine muscle and adipose tissue stored fresh and frozen. J. Food Sci. 47 1329-1332, 1337. 

In the Nurses Health Study (Hu et ah, 1997), the dietary intake of short- and medium-chained saturated fatty acids (4 0-10 0) was not significantly associated with CHD (but other saturated fatty acids were). In an intervention study a higher intake of medium-chained triglycerides was found to significantly decrease total adipose tissue, subcutaneous adipose tissue, and upper-body adipose tissue stores in men compared to longer chained triglyceride consumption (St-Onge, 2005). 

Adipose Tissue stores fats as triacylglycerol and releases fatty acids as needed for energy. 

Release of Lipid from Adipose Tissue Stores... 

Mixedmarasmus/kwashiorkor is a form of severe protein-calorie malnutrition that develops in chronically ill, starved patients during periods of hypermetabolic stress. There is reduced visceral protein synthesis superimposed on wasting of somatic protein and energy (adipose tissue) stores. Immunocompetence is lowered, increasing the incidence of infection, and wound healing is compromised. 

The source of the fatty acids can be dietary fat, fatty acids synthesized in the liver, or fatty acids released from adipose tissue stores. Adipose tissue lipolysis increases after ethanol consumption, possibly because of a release of epinephrine. 

Rashef and Shapiro (1960) reported that pretreatment of adrenalecto-mizc d rats with either epinephrine or eortisone inereased the depressed rate of free fatty acid release by their mesenteric adipose tissue in vitro however, maximal effects were, obtained only when both were given. It was further pointed out that epinephrine alone was highly effective in restorii the depressed rate of free fatty acid release by tissue from adrenal demedul-lated rats. Reshef and Shapiro (1960) also observed that pretreatment of starved intact rats with cortisone had little effect on the release of free fatty acid by mesenteric adipose tissue. Such treatment, however, inereased and prolonged the response of tissue removed from rats injected with epinephrine (sec Section VI, A). These results may reflect in part the effects of glucocorticoid administration on the adipose tissue stores of the intact animal, but the interesting relation between the effects of epinephrine and adrenocortical steroids on the release of free fatty acids deserves further study. 

Adults normally contain appreciable stores of essential fatty acids in their tissues and, even when none are supplied in the diet, it takes some time for deficiency symptoms to appear (Collins et al, 1971 Riella et al, 1975). On a high intake of polyunsaturated fat, the fatty acid composition of adipose tissue stores will gradually come to resemble that of the dietary fat, but again, this is a relatively slow process (Hirsch et al, 1960). Thus, in adults perhaps more so than in children, the requirements for dietary essential fatty acids may be considered in terms of long-term trends. 

By contrast, if the intake of metabolic fuels is greater than is required to meet energy expenditure, the body will spend more time in the fed state than the fasting state there will be more accumulation of nutrient reserves than utilization. The result of this is an increase in body size, and especially an increase in adipose tissue stores. If continued for long enough, this will result in overweight or obesity, with potentially serious health consequences — see Chapter 6. 

The concentration of free fatty acids in plasma is controlled by glucagon (which stimulates) and insulin (which inhibits) breakdown of triacylglycerols in adipose tissue stores (section 4.6.3). Once the fatty acids enter cells they can be degraded to acetyl-CoA or used for lipid synthesis. The relative rates of these two pathways depends on the nutritional state of the animal, particularly on the availability of carbohydrate. 

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