diphenylhexatriene and Weight-Gain

The effect of dietary protein, casein (CAS) and soybean protein (SOY), on linoleic acid desaturation in liver microsomes was studied in rats. The activity of delta 6 desaturase in total and rough endoplasmic reticula (ER and RER) was significantly higher in the CAS group than in the SOY group. In ER and smooth endoplasmic reticulum, the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene, when incorporated into the membrane, was decreased in the SOY group and accompanied by a reduction in the cholesterol/phospholipid (CHOL/PL) ratio, consistent with an increase in membrane fluidity. In a separate study, the effect of varying dietary proteins, CAS, milk whey protein, egg albumin, SOY, potato protein and wheat gluten, on the relationship between the delta 6 desaturase activity and microsomal membrane fluidity was also examined. The results indicated that the dietary protein-dependent change in the liver microsomal CHOL/PL ratio affected membrane fluidity, and subsequently the activity of delta 6 desaturase in liver microsomes. However, since dietary protein influenced the delta 6 desaturase activity in RER without influencing membrane fluidity, it is possible that some regulation might have taken place at the level of enzyme synthesis.

Topics: Animals; Caseins; Cholesterol; Dietary Proteins; Diphenylhexatriene; Endoplasmic Reticulum; Fatty Acid Desaturases; Fatty Acids; Fluorescence Polarization; Linoleic Acid; Linoleic Acids; Linoleoyl-CoA Desaturase; Male; Membrane Fluidity; Microsomes, Liver; Phospholipids; Plant Proteins, Dietary; Rats; Rats, Sprague-Dawley; Soybean Proteins; Weight Gain