Studies of the effects of insulin and glucose on the genexpression of mono and polyunsaturated fatty acids.

The body is unable to produce omega-3 and omega-6 (often written as n-3 and n-6). Hence, they have to be obtained from the diet. The process of manufacturing n-3 and n-6 polyunsaturated fatty acids has been the subject of extensive research in recent years. In the cell,the essential fatty acids 18:2 n-6 and 18:3 n-3 may be converted to various polyunsaturated fatty acids. ∆ 6 desaturase (D6D), ∆ 5 desaturase (D5D), elongation enzymes and oxidations are important to this process. Desaturase places new double bounds in the carbon chain. Stearic-acid 18:0, which is not an essential fatty acid, is similarly converted to monounsaturated 18:1 (n-9) by ∆ 9- desaturation. Altered lipid structures in the cell membran have been observed in many clinical conditions, such as in diabetes mellitus, heart disease and obesity. Deficiency in essential fatty acids is observable as skin alterations and neurological disturbances. Polyunsaturated fatty acids are central to the development of the brain in the foetus. Our studies has closer examined the way insulin and high glucose concentration effect the mRNA-expression of D6D,D5D and SCD-1. We compared also the mRNA concentrations of D6D,D5D and SCD-1 with the activity of these three enzymes, to see if there was any correlation between these three. Fresh and isolated rat hepatocytes were cultivated in primary cell cultures, and incubated with insulin and glucose. The mRNA expression and enzyme activity of D6D,D5D and SCD-1 was studied also. These studies show that insulin stimulates all three enzymes.High glucose concentration restrains D6D and D5D, while it stimulates SCD-1. This explains some of the altered lipid structures observed in the cellmembran in difficult regulated diabetes mellitus. The studies illustrate also a correlation between elevated mRNA concentration, and the actual activity of the enzymes