Blood Nonesterified fatty acids

Findings by Zammarchi et al.43 on blood free tryptophan levels in jaundiced newborn infants during phototherapy are of interest. They reported a significant decrease in free tryptophan levels 24 h after phototherapy. This was explained by the decrease in nonesterified fatty acids (NEFA) during phototherapy. Since both tryptophan and NEFA are bound to serum albumin and NEFA can displace tryptophan from their binding sites, the decrease in free tryptophan may be secondary to the change in NEFA levels. 

The ability of L-tryptophan to bind to plasma proteins of the blood and circulate as free and bound tryptophan is a unique feature for an amino acid. This binding is affected by and competes with other compounds that bind plasma proteins, such as nonesterified fatty acids (NEFA) and certain drugs. This relationship in blood affects its transport from the blood to the brain because only the free tryptophan is transplanted through the blood-brain barrier. Free tryptophan s concentration in blood in relation to other amino acids, particularly branched-chain amino acids (BCAA), affects its transport to the brain. 

Triacylglycerols are stored primarily in the adipose. Triacylglycerols can be hydrolyzed by lipases, one of which can be activated by glucagon or epinephrine. These hormones cause activation of hormone-sensitive lipase, which results in release of nonesterified fatty acids into the blood. 

Glucagon causes increases in cAMP in the adipose and liver. In the adipose this causes an increase in lipolysis and release of nonesterified fatty acids to the blood. These fatty acids stimulate gluconeogenesis in the liver and decreased use of glucose in the muscle. The increased cAMP in the liver results in increased glycogenolysis and increased gluconeogenesis, both of which help increase blood glucose levels. 

Egan, B. M., Greene, E. L., Goodfriend, T. L. (2001) Nonesterified fatty acids in blood pressure control and cardiovascular complications. Curr. Hypertens. Rep. 3 107-116. 

Detailed analysis of phospholipids, as well as neutral lipids and nonesterified fatty acids, has become progressively more important as these molecules have come to represent intercellular messenger molecules that are involved in a number of disease states. The analysis of lipid patterns of blood and lipoproteins may therefore constitute a useful diagnostic tool. As noted in the previous edition, suitable methods for phospholipid analysis are often time consuming and tedious, since most of them include several separation and derivatization steps. 

Figure 1. Changes of inducible heat shock protein 72 kDa molecular weight (Hsp72) in peripheral blood mononuclear cells (PBMC) (panel A), of plasma nonesterified fatty acids (NEFA) (panel B) and of the proliferative response oflipopolysaccharide-stimulatedPBMC (panel C) in peri-parturient dairy cows. Data are reported as least square means standard error. Different letters indicate significant differences between time points fP<0.05. Modifiedfrom Catalani et al. (2010).

Our own study examined the effects of a mixture of fatty acids on cortisol and cholesterol levels in laboratory stress situations. (Yehuda, al el, 2000). A compound of free nonesterified unsaturated fatty acids a-linolenic and linolenic acids in a ratio 1 4 was administered for 3 wk prior to injection of cortisone (10 mg/kg) or prior to immersion of rats in a 10°C saline bath. The results confirmed the expected elevation of cortisol and cholesterol level in stress, but, more importantly, the treatment prevented elevation of blood levels of cortisol and cholesterol and protected against deficits in the Morris water maze learning that usually accompany such stressful conditions. Differences from con-... 

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