This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Krause, R. Articles by Fischer, J. E. Search for Related Content PubMed PubMed Citation Articles by Krause, R. Articles by Fischer, J. E.

Plasma and Brain Amino Acids in Walker 256 Carcinosarcoma-bearing Rats¹

Department of Surgery [R. K., C. H., J. E. F.] and Surgical Physiology Laboratory [J. H. J.], Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114

Decreased food intake (anorexia) and competition for nutrients by malignant tumors both contribute to depletion of the tumor-bearing host. Tumor-induced changes in metabolic patterns of the host are superimposed upon the state of malnutrition, which, as concerns amino acid metabolism, results in altered amino acid patterns in plasma and brain.

Plasma amino acid profiles of anorectic Walker 256 carcinosarcoma-bearing rats, non-tumor-bearing pair-fed rats, and non-tumor-bearing freely feeding control rats were determined in an attempt to differentiate between tumor-related changes in amino acid metabolism and the effects of malnutrition. Elevated plasma concentration of alanine and tyrosine and lowered plasma total tryptophan were noted in both tumor-bearing and pair-fed groups and were attributed to decreased food intake and malnutrition. Decreased plasma levels of serine, glycine, aspartate, and hydroxyproline were found in tumorbearing rats only; these are presumably reflections of increased consumption of these amino acids by the tumor.

Brain amino acid concentrations were measured in all three groups of rats and discussed with reference to possible mechanisms in cancer anorexia. The results of previous studies suggested a relationship between the precursor amino acid tryptophan and the neurotransmitter serotonin and anorexia in tumor-bearing animals. Elevated concentrations of brain tyrosine in the present study might indicate some involvement of central catecholamine neurotransmitters in cancer anorexia.

¹ Supported in part by USPHS Grant 1RO1CA AM25786, and by USPHS Grant CA-25786.

² Present address: Department of Surgery, University of South Limburg, St. Annadal Ziekenhuis, Maastricht, Holland.

³ Present address: Department of Surgery, University of Cincinnati Medical Center, Cincinnati, Ohio 45267.

⁴ Present address: St. James Hospital Medical School, Leeds, United Kingdom.

⁵ Present address: Department of Surgery, University of Cincinnati Medical Center, 231 Bethesda Avenue, Cincinnati, Ohio 45267. To whom requests for reprints should be addressed.

Received 9/28/78. Accepted 5/ 2/79.