Distribution of dietary limiting amino acid injected into the prepyriform cortex.
Diffusion or metabolism of the dietary limiting amino acid (DLAA) in the prepyriform cortex (PPC) may account for the time lag between injection of the DLAA into the PPC and the increase in intake of an amino acid-imbalanced diet. Results from the injection of [3H]Leu +/- [14C]Thr (DLAA) into the PPC indicated rapid (less than 15 min) and limited diffusion (85-90% of recovered label was less than or equal to 1 mm from the injection site). 3H and 14C decreased in the trichloroacetic acid (TCA)-soluble fraction and increased in the TCA-insoluble fraction during the first 1.5 h and remained constant in the TCA-insoluble fraction 1.5-6 h after injection. An increase (approximately 50%) in 3H in the TCA-insoluble fraction was found less than or equal to 30 min after injection of the DLAA. There was no affect of the DLAA on 3H in the TCA-soluble fraction. These results indicated that a change in metabolism within the PPC may be responsible for the delay in onset of the feeding response after injection of the DLAA into the PPC.
Beverly
J L
JL
Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis 95616.
Hrupka
B J
BJ
Gietzen
D W
DW
Rogers
Q R
QR
D000596:Amino Acids / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D005591:Chemical Fractionation; D004032:Diet; D004058:Diffusion; D007267:Injections; D007930:Leucine / Q000493:pharmacokinetics; D008297:Male; D009833:Olfactory Pathways / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012995:Solubility; D013912:Threonine / Q000493:pharmacokinetics; D013997:Time Factors; D014238:Trichloroacetic Acid
D000596:Amino Acids; D013912:Threonine; D014238:Trichloroacetic Acid; D007930:Leucine