Skeletal muscle amino acid uptake is lower and alanine production is greater in late gestation intrauterine growth restricted fetal sheep hindlimb.

Skeletal muscle amino acid uptake is lower and alanine production is greater in late gestation intrauterine growth restricted fetal sheep hindlimb.
Am J Physiol Regul Integr Comp Physiol. 2019 Sep 04;:
Authors: Chang EI, Wesolowski SR, Gilje EA, Baker PR, Reisz JA, D'Alessandro A, Hay WW, Rozance PJ, Brown LD
Abstract
In a sheep model of intrauterine growth restriction (IUGR) produced from placental insufficiency, late gestation fetuses had smaller skeletal muscle mass, myofiber area, and slower muscle protein accretion rates compared to normally growing fetuses. We hypothesized that IUGR fetal muscle develops adaptations that divert amino acids (AA) from protein accretion and activate pathways that conserve substrates for other organs. We placed hindlimb arterial and venous catheters into late gestation IUGR (n=10) and control (CON, n=8) fetal sheep and included an external iliac artery flow probe to measure hindlimb AA uptake rates. Arterial and venous plasma samples and biceps femoris muscle were analyzed by mass spectrometry-based metabolomics. IUGR fetuses had greater abundance of metabolites enriched within the alanine, aspartate, and glutamate metabolism pathway compared to CON. Net uptake rates of branched chain AA (BCAA) were lower by 42-73% and muscle ammoniagenic AAs (alanine, glycine, and glutamine) were lower by 107-158% in IUGR hindlimbs versus CON. AA uptake rates correlated with hindlimb weight; the smallest hindlimbs...

Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 3, 2019 Category: Physiology Authors: Chang EI, Wesolowski SR, Gilje EA, Baker PR, Reisz JA, D'Alessandro A, Hay WW, Rozance PJ, Brown LD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research