Regulatory signals for intestinal amino acid transporters and peptidases
- Univ. of California Medical School, Los Angeles (USA)
Dietary protein ultimately regulates many processes involved in protein digestion, but it is often unclear whether proteins themselves, peptides, or amino acids (AAs) are the proximate regulatory signal. Hence the authors compared several processes involved in protein digestion in mice adapted to one of three rations, identical except for containing 54% of either casein, a partial hydrolysate of casein, or a free AA mixture simulating a complete hydrolysate of casein. The authors measured brush-border uptakes of seven AAs that variously serve as substrates for four AA transporters, and brush-border and cytosolic activities of four peptidases. The three rations yielded essentially the same AA uptake rates. Peptidase activities tended to be lower on the AA ration than on the protein ration. In other studies, all three rations yielded the same rates of brush-border peptide uptake; protein is only modestly more effective than AAs at inducing synthesis of pancreatic proteases; and, depending on the animal species, protein is either much less or much more effective than AAs at stimulating release of cholecystokinin and hence of pancreatic enzymes. Thus the regulators of each process involved in protein digestion are not necessarily that process's substrate.
- OSTI ID:
- 6808785
- Journal Information:
- American Journal of Physiology; (USA), Vol. 255:2; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
60 APPLIED LIFE SCIENCES
AMINO ACIDS
INTESTINAL ABSORPTION
NONSPECIFIC PEPTIDASES
BIOCHEMICAL REACTION KINETICS
PORINS
ALANINES
CARBON 14 COMPOUNDS
DIGESTION
DOSE-RESPONSE RELATIONSHIPS
GLUCOSE
GLUTAMIC ACID
LEUCINE
LYSINE
MEMBRANE TRANSPORT
PEPTIDE HYDROLASES
PHENYLALANINE
POLYETHYLENE GLYCOLS
SMALL INTESTINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ABSORPTION
ALCOHOLS
ALDEHYDES
BODY
CARBOHYDRATES
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
ENZYMES
GASTROINTESTINAL TRACT
GLYCOLS
HEXOSES
HYDROGEN COMPOUNDS
HYDROLASES
HYDROXY COMPOUNDS
INTESTINES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
ORGANS
POLYMERS
PROTEINS
REACTION KINETICS
SACCHARIDES
UPTAKE
551001* - Physiological Systems- Tracer Techniques
553005 - Agriculture & Food Technology- Animal Husbandry- (1987-)
550201 - Biochemistry- Tracer Techniques