Uptake of polypeptide fragments of proteins by rat intestine in vitro and in vivo
Minute amounts of intact proteins were previously shown to be taken up from the intestine into the systemic circulation of mature animals; fragments were not detected. In this study, we sought evidence for uptake of fragments in both in vitro and in vivo experiments. Polypeptide fragments produced by pepsin digestion of bovine serum albumin (ranging in molecular weight from approximately 6000 to 25,000) were labeled with /sup 125/I. Everted jejunal gut sacs prepared from rat intestine were incubated with labeled fragments. After incubation, fluid exposed to the serosal surface was applied to a Sephadex G-50 gel permeation column. Radioactivity was detected in fractions corresponding to the elution position of the fragments. Transfer of fragments from the mucosal to the serosal surface was temperature-dependent. In in vivo studies, labeled fragments were infused into the jejunum of rats. Blood samples obtained from a mesenteric vein or the portal vein contained labeled fragments. After infusion of unlabeled fragments, nanogram amounts of immunoreactive fragments were detected by radioimmunoassay of mesenteric and portal venous blood. Thus, polypeptide fragments of a potential food protein were capable of being transferred across the mucosa in vitro and in vivo. Failure to detect fragments in the systemic circulation most likely results from their rapid clearance.
- Research Organization:
- Harvard Medical School, Boston, MA (USA)
- OSTI ID:
- 6797838
- Journal Information:
- Gastroenterology; (United States), Vol. 95:5
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of the renin-angiotensin system in the regulation of intestinal blood flow and sympathetic neurotransmission
Processing of epidermal growth factor by suckling and adult rat intestinal cells
Related Subjects
POLYPEPTIDES
INTESTINAL ABSORPTION
SMALL INTESTINE
PHYSIOLOGY
IN VITRO
IN VIVO
IODINE 125
MEMBRANE TRANSPORT
MOLECULAR WEIGHT
RADIOIMMUNOASSAY
RATS
TEMPERATURE DEPENDENCE
ABSORPTION
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
GASTROINTESTINAL TRACT
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
INTESTINES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PROTEINS
RADIOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RODENTS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques