Beta-casomorphins stimulate and enterostatin inhibits the intake of dietary fat in rats.
The effects of beta-casomorphins 1-7, 1-5 and 1-4 on food intake of rats adapted to either a high fat (HF) or high carbohydrate (HC) diet have been studied and compared to the effects of enterostatin. Intracerebroventricular (icv) beta-casomorphin1-7 (beta-CM1-7) stimulated intake of HF diet in overnight fasted rats, but beta-CM1-5 and beta-CM1-4 were ineffective. Peripheral injection of beta-CM1-7 also increased the intake of a high fat diet, but reduced the intake of HC diet in satiated rats. Intracerebroventricular (ICV) beta-CM1-7 caused a dose-dependent increase in the intake of HF diet, but a dose-dependent inhibition of HC ingestion in satiated rats. Enterostatin (ICV) inhibited the beta-CM1-7 stimulation of HF intake, as did the general opioid antagonist naloxone. Ligand binding studies with [3H-pro] enterostatin identified on low affinity binding site (Kd 100nM) on a crude brain membrane preparation. This binding was displaced by beta-CM1-7, beta-CM1-5 and beta-CM1-4. These data suggest that at high doses enterostatin and beta-CM1-7 may interact with the same low affinity receptor to modulate intake of dietary fat.
Lin
L
L
Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808-4124, USA.
Umahara
M
M
York
D A
DA
Bray
G A
GA
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D003089:Colipases / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage*; D004435:Eating / Q000187:drug effects* / Q000502:physiology*; D004723:Endorphins / Q000737:chemistry / Q000494:pharmacology*; D004792:Enzyme Precursors; D007700:Kinetics; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003089:Colipases; D004041:Dietary Fats; D004723:Endorphins; D004792:Enzyme Precursors; D010446:Peptide Fragments; D011498:Protein Precursors; D009270:Naloxone; C041128:beta-casomorphin 7; C034812:beta-casomorphin 5; C037107:procolipase; C043158:beta-casomorphin 4; C021968:beta-casomorphins