Lipids interrelationship

Coles, B.L. and MacDonald, I. The influence of dietary protein on dietary carbohydrate lipid interrelationships... 

An unusual approach to the study of dietary carbohydrate lipid interrelationships is the estimation in tissue culture of intracellular lipid disposition in human aortic cells grown in the serum from men subjected to various dietary procedures (Rutstein et al., 1964). It was found that carbohydrate ingestion was followed by a suppression of intracellular lipid deposition and that this occurred in the absence of any changes in the concentration of glycerides, phospholipids, or cholesterol in the serum. 

Thus the alpha and the omega of dietary carbohydrate and its eifect on lipid metabolism are to some extent known. The intermediate stages are obscure and would involve consideration of the metabolic role of fructose, the physical and biochemical aspects of absorption, the influence of dietary carbohydrates on gut microflora and in tmn their effect on lipid metabolism, and the possibility that metabolic pathways show some adaptation to dietary carbohydrates. The lipid responses to dietary carbohydrates reflect differences in the type of carbohydrate eaten, in the sex and age of the individual eating it, in the amount consumed, and in the nature of the accompanying dietary lipid. There are many variables and the disclosure of the intermediate stages of the dietary carbohydrate Lipid interrelationships will therefore need careful and precise study. 

Saz, H.J. and Lescure, O.L. (1966) Interrelationships between the carbohydrate and lipid metabolism of Ascaris lumbricoides egg and adult stages. Comparative Biochemistry and Physiology 18, 845-857. 

Generally, to produce a biological response, a drug molecule must first cross at least one biological membrane. The biological membrane acts as a lipid barrier to most drugs and permits the absorption of lipid-soluble substances by passive diffusion while lipid-insoluble substances can diffuse if at all across the barrier only with considerable difficulty. The interrelationship of the dissociation constant, lipid solubility, and pH at the absorption site and absorption characteristics of various drugs are the basis of the pH-partition theory. 

The metabolism of cholesterol in mammals is extremely complex. A summary sketch (fig. 20.24) helps to draw the major metabolic interrelationships together. Cholesterol is biosynthesized from acetate largely in the liver (fig. 20.24a) or taken in through the diet (fig. 20.24b). From the intestine, dietary cholesterol is secreted into the plasma mainly as a component of chylomicrons. The triacylglycerol components of chylomicrons are quickly degraded by lipoprotein lipase, and the remnant particles are removed by the liver. Apoproteins and lipid components of the chylomicrons and remnants appear to exchange with HDL. Cholesterol made in the liver (fig. 20.24a) has several alternative fates. It can be (1) secreted into plasma as a component of VLDL,... 

Relatively little is known about the possible interrelationships of the metabolism of the complex sugar-containing lipids, the glycosphingolipids (GSLs) and the plasma lipoproteins. 

The interrelationship between the dissociation constant and lipid solubility of a drag, as well as the pH at the absorption site, is known as the pH-partition theory of drag absorption. Accordingly, rapid transcellular passive diffusion of a drag molecule may be due to ... 

In addition to being incorporated into tissue proteins, amino acids, after losing their nitrogen atoms by deamination and/or transamination, may be catabolized to yield energy or to form glucose. Conversely, the nonessential amino acids may be synthesized from carbohydrate metabolism intermediates and ammonia or from essential amino acids. This section is devoted to the mechanisms of such metabolic processes and their interrelationships with carbohydrate and lipid metabolic pathways. 

Carman, G.M., and Henry, S.A., 1999, Phospholipid biosynthesis in the yeast Saccharomyces cerevisiae and interrelationship with other metabolic processes. Prog. Lipid Res. 38 361-399. Chang, H.J., 2001, Role of the unfolded protein response pathway in phospholipid biosynthesis and membrane trafficking in Saccharomyces cerevisiae. Department of Biological Sciences, Carnegie Mellon University. 

Metabolism will be studied in various parts. Interrelationships will be pointed out as they are encountereD. Just as there are three basic biomolecules -carbohydrates, lipids, and proteins, the metabolism of each of these will be studied individually. 

Fig. 3. Metabolic interrelationships of lipoproteins (lipoprotein abbreviations are as given in Table I). LpL, Lipoprotein lipase LCAT, lecithin-cholesterol acyltransferase HL, hepatic lipase CETP, cholesteryl ester transfer protein. Solid lines represent interconversion of particles regular dashed lines represent movement of cholesterol irregular dashed lines represent transfer of lipids mediated by CETP.

Significantly, inflammation and lipid metabolism exhibit close functional interrelationships and are subject to coordinate, reciprocal regulation. PPARy and LXRs have been reported to reciprocally regulate genes involved in both immunity and lipid metabolism [6,90]. While the primary focus of the action of PPARy in inflammation has focused on receptor-mediated inhibition of inflammatory gene expression, there is a reciprocal effect of inflammation on nuclear hormone expression. Feingold and colleagues have extensively examined the inflammation-mediated suppression of PPARy and RXR expression [91]. 

Interrelationships of tissues in lipid metabolism are discussed in Chapter 22. 

Huang YS, Koba K, Horrobin DF, Sugano, M. Interrelationship between dietary protein, cholesterol and n-6 polyunsaturated fatty acid metabolism. Prog Lipid Res 1993 32 123-137. 

Bast, A. and Haenen, G.R.M.M. (1984) Cytochrome P-450 and glutathione what is the significance of their interrelationship in lipid peroxidation Trends Biol. Sci. 9 510-513. 

A3. Aftergood, L., and Alfin-Slater, R. B., Oral contraceptive-a-tocopherol interrelationships. Lipids 9, 91-96 (1974). 

Caldwell, J. Marsh, M.V. Interrelationships between xenobiotic metabolism and lipid biosynthesis. Biochem. Pharmacol. 1983, 32, 1667-1672. 

The authors attributed the variation by production year to environmental factors, although specific factors and the interrelationships to lipid content were not defined. 

Huang, Y.-S., Koba, K., Horrobin, D.F., and Sugano, M. (1993) Interrelationship Between Dietary Protein, Cholesterol and n-6 Polyunsaturated Patty Acid Metabolism, Prog. Lipid Res. 32,123-137. 

---