Growth inhibition of subcutaneously transplanted hepatomas without cachexia by alteration of the dietary arginine-methionine balance.
Previous studies have shown that alteration of the dietary arginine-methionine balance by use of synthetic L-amino acids inhibits tumor growth of a subcutaneously transplanted Morris hepatoma at the expense of maintaining body weight. However, L-methionine is susceptible to degradation and, therefore, may contribute to a deficiency state. The present studies were performed to determine whether growth of subcutaneous hepatoma transplants is inhibited, and body growth maintained, when rats are fed diets containing L-methionine in replacement of N-acetyl-L-methionine (NALM) for 28 days. Tumor-free and tumor-bearing rats fed a control diet, with amino acids replacing protein, had gains in body weight: 31.3 +/- 1.0 and 19.1 +/- 0.5 g (12% and 7%), respectively. Rats fed six experimental diets, with varying L-arginine-NALM balances, had body weight gains ranging from 18.4 +/- 0.3 to 26.7 +/- 0.9 g (7-10%). Tumor weight of control rats was 10.65 +/- 0.24% of body weight. Diets supplemented with L-arginine in combination with normal and deficient NALM decreased tumor weights by 35% and 38%, respectively, It is concluded that dietary replacement of L-methionine with NALM and supplementation with L-arginine inhibits growth of a subcutaneously transplanted Morris hepatoma in the absence of cachexia.
Department of Physiology and Biophysics, Howard University, Washington, DC 20059, USA.
R M
RM
Millis
C A
CA
Diya
M E
ME
Reynolds
O
O
Dehkordi
V
V
Bond
D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D002100:Cachexia; D004032:Diet; D008114:Liver Neoplasms, Experimental / Q000473:pathology* / Q000517:prevention & control; D008297:Male; D008715:Methionine / Q000008:administration & dosage* / Q000031:analogs & derivatives; D009368:Neoplasm Transplantation; D051381:Rats; D011912:Rats, Inbred ACI; D015430:Weight Gain
D001120:Arginine; C006379:N-acetylmethionine; D008715:Methionine