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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #141897
Title: INSULIN AND AMINO ACIDS INDEPENDENTLY STIMULATE TRANSLATION INITIATION IN NEONATAL MUSCLE

Author
item DAVIS, TERESA - BAYLOR COLLEGE OF MED
item SURYAWAN, AGUS - BAYLOR COLLEGE OF MED
item O'CONNOR, PAMELA - BAYLOR COLLEGE OF MED
item BUSH, JILL - BAYLOR COLLEGE OF MED
item NGUYEN, HANH - BAYLOR COLLEGE OF MED
item LIU, CHUN - BAYLOR COLLEGE OF MED
item JEFFERSON, L - PENN STATE UNIVERSITY
item KIMBALL, SCOT - PENN STATE UNIVERSITY

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2001
Publication Date: 6/6/2001
Citation: DAVIS, T.A., SURYAWAN, A., O'CONNOR, P.M., BUSH, J.A., NGUYEN, H.V., LIU, C.W., JEFFERSON, L.S., KIMBALL, S.R. INSULIN AND AMINO ACIDS INDEPENDENTLY STIMULATE TRANSLATION INITIATION IN NEONATAL MUSCLE. JOURNAL OF FEDERATION OF AMERICAN SOCIETIES FOR EXPERIMENTAL BIOLOGY. 2001.

Interpretive Summary: Not required for an abstract.

Technical Abstract: The stimulation of muscle protein synthesis by feeding is profound in neonates resulting in rapid muscle growth. The feeding-induced stimulation of muscle protein synthesis is accompanied by marked increase in the activation of translation initiation factors involved in the binding of mRNA to the 40S robosomal subunit. To determine the role of insulin and amino acids (AA) in this process, we performed somatostatin clamps in overnight fasted 7-day-old pigs. Pigs (n=9-12/group) were infused with 0, 10, 22, and 110 ng insulin/kg 0.66/min to achieve 0, 2, 6, and 30 micro units/ml plasma insulin, and AA were maintained at fasting levels or 2-fold elevated. The amount of the mRNA cap-binding protein, eIF4E, in the inactive 4E-BP1.eIF4E complex was reduced and the amount of eIF4E in the active eIF4E.eIF4G complex was increased with increasing insulin doses. The insulin-induced dissociation of the 4E-BP1.eIF4E complex was accompanied by phosphorylation of the eIF4E repressor protein,4E-BP1, in a dose response manner. Phosphorylation of p70 S6 kinase was increased at the highest insulin dose. AA increased the activation of these factors at each insulin dose. Insulin, but not AA, increased the phosphorylation of protein kinase B. Insulin and AA had no effect on eIF4E phosphorylation or eIF2B activity. These results suggest that post-prandial rise in insulin and AA independently increase the availability of eIF4E for 48S ribosomal complex formation leading to a marked stimulation of muscle protein synthesis in the neonate.