Lung subcellular fractions and surfactant lipid metabolism of rats exposed with DDT or endosulfan intratracheally

The effect of intratracheally administered DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) for three consecutive days has been studied on lipid metabolism of rat lung subcellular fractions. Both the insecticides did not affect the lung weight and the protein contents of microsomes, lamellar bodies and surfactant but significantly increased the phospholipid contents of microsomal and surfactant system. Most of the neutral lipid components of lung subcellular fractions were also increased by DDT or endosulfan treatments, except that of surfactant triglycerides which were decreased by DDT treatment. DDT or endosulfan both increased the incorporation of radioactive [methyl-3H]choline into microsomal phosphatidylcholine (PC) and surfactant dipalmitoylphosphatidylcholine (DPPC) without affecting the incorporation of radioactive [methyl-14C]methionine, showing the increased synthesis of PC via CDPcholine pathway. The results presented in this communication showed that DDT and endosulfan, the two different chloroinsecticides have similar effects on microsomal lipid metabolism but produce different biochemical manifestations on the secretion of surfactant phospholipids.     

Changes in lipid profiles of liver microsomes of rats following intratracheal administration of DDT or endosulfan

Abstract

The effect of intratracheal administration of DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) to rats for three consecutive days, has been studied on liver lipid metabolism. The administration of DDT but not endosulfan significantly increased the liver weight and the microsomal protein contents. Both DDT and endosulfan treatments significantly increased the contents of microsomal phosphatidylcholine (PC), total‐free‐ and esterified cholesterol. The distribution of unsaturated fatty acids of microsomal PC and PE was increased by DDT treatment. The intratracheal administration of DDT caused fatty infiltration of liver which was probably due to increased synthesis of triglycerides (TG). This is supported by the increased incorporation of radioactive palmitate‐l‐¹⁴C into microsomal TG. However, the increased incorporation of palmitate‐l‐¹⁴C into microsomal PC and phosphatidylethanolamine (PE) after the DDT treatment, was due to the increased transacylation reaction supported by the decreased activity of microsomal phospholipase A. The intratracheal adminstration of endosulfan did not has pronounced effect on liver fatty infiltration, or transacylation reaction in microsomal PC and PE. However, the results have shown that the treatments of DDT or endosulfan increased the PC contents and the incorporation of radioactive [methyl‐³H]choline into PC of microsomes, resulting the increased synthesis of PC via CDPcholine pathway. Thus, the intratracheally administered DDT or endosulfan to rats showed that both the insecticides cause manifestations in the biochemistry of microsomal membrane lipids, although the effects of DDT being more pronounced. Therefore, the translocation effects of these insecticides or metabolites from lung to liver is established.