Lipid changes in the tadpoles of Rana tigrina during growth and metamorphosis

Abstract

1. 1. Total lipids, neutral lipids and phospholipids of tadpoles of Rana tigrina were studied during their growth and metamorphosis. 2. 2. Total lipids increased during the growth period and early prometamorphosis but decreased during late prometamorphosis and metamorphosis. In young adult growth stages they showed a gradual increase. 3. 3. Neutral lipids consisted of triglycerides as the major fraction, cholesterol, cholesterol esters and diglycerides in moderate concentration and monoglycerides and free fatty acids in low concentration. Quantitative alterations in neutral lipids and all the components except fatty acids paralleled those occurring in total lipids. Fatty acids increased during the growth period and entire prometamorphosis and early metamorphosis but showed some decrease in late metamorphosis. 4. 4. Phosphatidyl choline and phosphatidyl ethanolamine were major phospholipid components. Phosphatidyl inositol, phosphatidyl serine and spingomyelin occurred in moderate concentrations, whereas lysophosphatidyl choline and phosphatidic acid occurred in trace amounts. Quantitative alterations in phospholipids and their individual components paralleled those observed in total and neutral lipids. 5. 5. Composition and alterations in total, neutral and phospholipids of anuran tadpoles in growth and metamorphosis are compared with the same in the insect larvae in growth and metamorphosis. 6. 6. The significance of alterations in lipids during histogenesis and histolysis occurring in anuran metamorphosis is presented and discussed.