Elevated blood lactate is not a primary cause of anorexia in tumor-bearing rats.
Tumor-bearing (TB) rats exhibit elevated concentrations of lactate in blood contiguous with the development of anorexia. Continuous intravenous infusion of lactate into non-TB rats reduced food intake at plasma concentrations lower than those observed in anorectic TB rats. Levels of neuropeptide Y (NPY) were elevated in the ventromedial (VMH) and dorsomedial hypothalamic regions of lactate-infused rats. The addition of the enhancer of pyruvate dehydrogenase activity, dichloroacetate (DCA), to the drinking water of TB rats (0.1-0.4%) normalized blood lactate concentration but had no significant effect on anorexia. However, the elevated concentration of NPY in the VMH of anorectic TB rats was also normalized by the DCA treatment. No alterations in regional hypothalamic levels of corticotropin-releasing factor were observed within any treatment conditions. These results suggest that, although hyperlactatemia may be involved in maintaining elevated NPY concentrations in anorectic TB rats, it does not appear to be a significant factor in the etiology of experimental cancer anorexia.
Chance
William T
WT
Medical Research Service, Veterans Affairs Medical Center, Cincinnati, OH, USA. William.Chance@UC.Edu
Dayal
Ramesh
R
Friend
Lou Ann
LA
James
J Howard
JH
D000818:Animals; D000855:Anorexia / Q000097:blood / Q000209:etiology*; D003999:Dichloroacetic Acid / Q000008:administration & dosage; D007033:Hypothalamus, Middle / Q000378:metabolism*; D007773:Lactates / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000097:blood*; D008297:Male; D009374:Neoplasms, Experimental / Q000097:blood* / Q000150:complications; D009478:Neuropeptide Y / Q000097:blood*; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344
D007773:Lactates; D009478:Neuropeptide Y; D003999:Dichloroacetic Acid