Question

Explain how Gln is used as energy by enterocytes, lymphocytes, and macrophages and major end products for each

Answer 1

1. Glutamine stimulates protein synthesis and reduces ubiquitin-dependent proteolysis in the enterocyte since this amino acid reduces ubiquitin gene expression. Glutamine can increase the gene expression of the arginine-succinate synthase enzyme in Caco-2 cells (human colon epithelial-line cell).

2. GLUTAMINE UTILIZATION BY LYMPHOCYTES

A.There are several lines of evidence which support the view that glutamine metabolism is important for lymphocytes and hence for the immune response of the body.

B. Lymphocytes, other lymphoid tissues and rapidly dividing cells possess high activities
of phosphate-dependent glutaminase.

C. Glutaminase activity is increased during an immunological challenge in vivo.

D. Lymphocytes isolated from rat mesenteric lymph nodes and incubated under aerobic
conditions.

E. Glumtamine is essential for cell division of lymphocytes in culture.

F. The major end-products of glutamine metabolism in lymphocytes are glutamate,
aspartate and ammonia .

3.Glutamine (the most abundant amino acid in the plasma of humans and many other mammals including rats) is effective in inducing polarization of M2 macrophages through the glutamine–UDP-N-acetylglucosamine pathway and α-ketoglutarate produced via glutaminolysis, whereas succinate synthesized via glutamine-dependent anerplerosis or the γ-aminobutyric acid shunt promotes polarization of M1 macrophages.