Glutamine metabolism stimulates intestinal cell MAPKs by a cAMP-inhibitable, RAF-independent mechanism

Abstract

Increased levels of intracellular cAMP inhibit ERKs but only partially reduce glutamine-stimulated proliferation in enterocytes adapted to low glutamine.

Guanylyl cyclase C agonists regulate progression through the cell cycle of human colon carcinoma cells

“…Proliferation induced by serum of SW480 human colon carcinoma cells, which do not express GC-C (29), was not affected by ST. Similarly, ST (1 M) reduced (32,33). Proliferation of T84 cells stimulated by 10 mM L-glutamine, quantified by cell number, was inhibited by 1 M ST (PBS, 171.41% Ϯ 7.98 vs. ST, 92.74% Ϯ 11.54, P Ͻ 0.05).…”

“…Proliferation was induced by serum (10%), and by L-glutamine (10 mM), a specific mitogen for intestinal cells (32,33). ST inhibited proliferation of T84 and Caco2 cells in a concentration-dependent fashion with nanomolar potency.…”

Gastric Inhibitory Peptide Controls Adipose Insulin Sensitivity via Activation of cAMP-response Element-binding Protein and p110β Isoform of Phosphatidylinositol 3-Kinase

“…To further explore the requirement for cAMP in the GIP enhancement of insulin action, we used a membrane-permeant cAMP analog, 8-(4-chlorophenylthio)-adenosine-3Ј,5Ј-cyclic monophosphate (8-CPT-cAMP), which mimics some effects of elevated cAMP (39,40). 8-CPT-cAMP, in a dose-dependent manner, restored the GIP enhancement of insulin-stimulated Glut4 translocation in adipocytes in which adenylate cyclase was inhibited by P-site, confirming a requirement for elevated cAMP (Fig.…”

Mammalian Target of Rapamycin and Protein Kinase A Signaling Mediate the Cardiac Transcriptional Response to Glutamine

“…Recent studies indicate that glutamine is a major gluconeogenic precursor and vehicle for interorgan carbon transport in man (19). It has long been known that under certain physiological circumstances glutamine serves as major fuel for the gut (20,21), the kidney (22), and the immune system (23-26). Many lines of cultured mammalian cells utilize glutamine, in preference to glucose, as their major carbon source to meet energetic and biosynthetic needs (24,25).…”