Free amino acid composition of the intestinal contents,intestinal cells and hemolymph ofPhilosamia cynthia larvae

Summary Free amino acid composition of the intestinal contents, intestinal cells and hemolymph has been determined in larvae of the mothPhilosamia cynthia. From the hemolymph/lumen concentration ratio, an active transport could be inferred for neutral and basic amino acids. The values of cell/lumen and hemolymph/cell ratios suggested that the active step in the transport mechanism could be localized at the luminal pole of the enterocyte for neutral amino acids (except aromatic amino acids) and at the basolateral pole of the enterocyte for basic amino acids (except arginine).This work was supported by grants from Italian Consiglio Nazionale delle Ricerche and from Ministero della Pubblica Istruzione, Rome. The authors are indebted to Prof. V. Capraro for helpful discussion.