Regulation of membrane transport and metabolism in the HT29 human colonic adenocarcinoma cell line

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1988

OSTI ID:5526530

Franklin, C C

The effects of insulin on glucose transport and metabolism were examined in cultured HT29 human colonic adenocarcinoma cells. The presence of glucose transporters was verified by D-glucose displaceable ({sup 3}H) cytochalasin B binding. Moreover, two classes of insulin binding sites were detected in radioligand binding experiments. Despite the presence of both glucose transporters and insulin receptors, insulin failed to stimulate glucose transport. However, insulin was found to activate glycolysis. These findings suggest that insulin directly influences substrate utilization through the glycolytic pathway in HT29 cells without activating the glucose transport pathway. A Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway was also detected in HT29 cells using {sup 86}Rb{sup +} as a K{sup +} congener. The identity of this pathway as a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransporter has been deduced from the following findings: (1) {sup 86}Rb{sup +} influx was inhibited by loop diuretics, (2) {sup 86}Rb{sup +} influx ceased in the absence of any one of the transported ions, and (3) cotransport exhibited a stoichiometry approaching 1Na{sup +}:1K{sup +}:2Cl{sup {minus}}. Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was found to be exquisitely sensitive to cellular ATP and cyclic AMP levels. These results suggest that HT29 cells contain a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway that can be regulated by the second messenger cyclic AMP and is highly sensitive to the metabolic state of the cell. The involvement of protein kinase C in the regulation of Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was also investigated. Phorbol 12-myristate 13-acetate (PMA), which stimulated protein kinase C activity, produced a transient increase in cotransport followed by a near abolition of cotransport by 2 h.

• Research Organization: Missouri Univ., Columbia, MO (USA)
• OSTI ID: 5526530
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
560300 -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALDEHYDES
ALKALI METAL COMPOUNDS
AMP
ANIMAL CELLS
ANIMALS
ATP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BODY
CARBOHYDRATES
CARCINOGENS
CARCINOMAS
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ENZYME ACTIVITY
ENZYMES
ESTERS
GASTROINTESTINAL TRACT
GLUCOSE
HALIDES
HALOGEN COMPOUNDS
HEXOSES
HORMONES
HYDROGEN COMPOUNDS
INSULIN
INTERMEDIATE MASS NUCLEI
INTESTINES
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LARGE INTESTINE
MAMMALS
MAN
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
METABOLISM
MINUTES LIVING RADIOISOTOPES
MONOSACCHARIDES
NEOPLASMS
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PHORBOL ESTERS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
POTASSIUM COMPOUNDS
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RUBIDIUM 86
RUBIDIUM ISOTOP
SACCHARIDES
SODIUM COMPOUNDS
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
TUMOR CELLS
VERTEBRATES