Decreased maternal and placental concentrations of follistatin-like 3 in gestational diabetes
CLINICA CHIMICA ACTA
Authors: Hu, Dongxiao; Tian, Ting; Guo, Jing; Wang, Hanzhi; Chen, Danqing; Dong, Minyue
Background: The objective of this study was to determine maternal and placental concentrations of follistatin-like 3 (FSTL3), and, maternal concentrations of myostatin in gestational diabetes mellitus (GDM). Methods: 40 women with GDM of term pregnancy were recruited and 40 maternal age- and gestational age-matched normally pregnant women served as control. Maternal blood samples and placental tissues were collected. Maternal concentrations of FSTL3 and myostatin were determined by enzyme-linked immunosorbent assay (ELISA), and, placental concentrations of FSTL3 by Western blotting. Results: Women with GDM had significantly lower serum FSTL3 concentrations than controls (P = 0.001). Placental concentrations of FSTL3 were significantly lower in GDM group than in controls (P<0.001). Women with GDM had significantly higher homeostasis model assessment of insulin resistance (HOMA-IR) and glycosylated hemoglobin (HbAlc) than control women (P = 0.042 and <0.01, respectively). Maternal serum myostatin was not significantly different between GDM and control groups (P = 0.312). Conclusions: Maternal and placental FSTL3 concentrations were reduced in GDM women compared with normally pregnant women, suggesting FSTL3 may play an important role in the pathogenesis of gestational diabetes. (C) 2011 Elsevier B.V. All rights reserved.
Effects of pre-exercise feeding on serum hormone concentrations and biomarkers of myostatin and ubiquitin proteasome pathway activity
EUROPEAN JOURNAL OF NUTRITION
Authors: Dalbo, Vincent J.; Roberts, Michael D.; Hassell, Scott; Kerksick, Chad M.
The aim of the study was to examine the acute effects of pre-exercise ingestion of protein, carbohydrate, and a non-caloric placebo on serum concentrations of insulin and cortisol, and the intramuscular gene expression of myostatin- and ubiquitin proteasome pathway (UPP)-related genes following a bout of resistance exercise. Ten untrained college-aged men participated in three resistance exercise sessions (3 x 10 at 80 % 1RM for bilateral hack squat, leg press, and leg extension) in a cross-over fashion, which were randomly preceded by protein, carbohydrate, or placebo ingestion 30 min prior to training. Pre-supplement/pre-exercise, 2 h and 6 h post-exercise muscle biopsies were obtained during each session and analyzed for mRNA fold changes in myostatin (MSTN), activin IIB, follistatin-like 3 (FSTL3), SMAD specific E3 ubiquitin protein ligase 1 (SMURF1), forkhead box O3, F-box protein 32 (FBXO32), and Muscle RING-finger protein-1, with beta-actin serving as the housekeeping gene. Gene expression of all genes was analyzed using real-time PCR. Acute feeding appeared to have no significant effect on myostatin or UPP biomarkers. However, resistance exercise resulted in a significant downregulation of MSTN and FBXO32 mRNA expression and a significant upregulation in FSTL3 and SMURF1 mRNA expression (p < 0.05). An acute bout of resistance exercise results in acute post-exercise alterations in intramuscular mRNA expression of myostatin and UPP markers suggestive of skeletal muscle growth. However, carbohydrate and protein feeding surrounding resistance exercise appear to have little influence on the acute expression of these markers.