Effects of nutritional lipids on diabetic manifestations and delta6 desaturase mRNA level in streptozotocin treated mice

delta6 desaturase is the key enzyme in the metabolism of essential fatty acids leading to prostaglandins. The decreased enzyme activity in diabetes creates metabolic complications. We investigated the ability of dietary lipids to influence the delta6 desaturase at the mRNA level and to normalize diabetic phenotype in streptozotocin (STZ)-injected mice. The animals received diets supplemented with 2% palmitic acid (PD) or soybean oil (SD). Liver delta6 desaturase mRNA level decreased 60% in STZ-injected mice. Both PD and SD restored it, but only SD serum fatty acid composition was normal. Pancreas histology was damaged in animals treated with STZ and PD but not SD. Insulinemia, 80% lower in STZ-treated animals, was normalized only by SD. Glucose tolerance curve was also normal in SD. The present data show that the nutritional lipids tested restore the low delta6 desaturase expression independently of insulin. However, only SD enabled normal enzyme activity and prevented STZ-induced pancreatic damage.