Uptake of polypeptide fragments of proteins by rat intestine in vitro and in vivo

Journal Article · Tue Nov 01 04:00:00 EST 1988 · Gastroenterology; (United States)

OSTI ID:6797838

Bloch, K J; Wright, J A; Bishara, S M; Bloch, M B

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), Journal Name: Gastroenterology; (United States) Vol. 95:5; ISSN GASTA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
GASTROINTESTINAL TRACT
IMMUNOASSAY
IMMUNOLOGY
IN VITRO
IN VIVO
INTERMEDIATE MASS NUCLEI
INTESTINAL ABSORPTION
INTESTINES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANE TRANSPORT
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PHYSIOLOGY
POLYPEPTIDES
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RATS
RODENTS
SMALL INTESTINE
TEMPERATURE DEPENDENCE
TRACER TECHNIQUES
UPTAKE
VERTEBRATES