Acute bout of resistance exercise increases vitamin D receptor protein expression in rat skeletal muscle.
Exp Physiol. 2015 Sep 7. Epub 2015 Sep 7. PMID: 26347486
Vitamin D and vitamin D receptor (VDR) are involved in maintaining skeletal muscle mass and function. Although resistance exercise is well known to enhance muscle growth and improve muscle function, the effect of resistance exercise on VDR has been unclear. We investigated intramuscular VDR expression in response to an acute bout of resistance exercise and endurance exercise. Male adult Sprague-Dawley rats were subjected to either resistance exercise (isometrically exercised via percutaneous electrical stimulation for 5 sets of ten 3-s contractions, with a 7-s interval between contractions and 3-min rest intervals between sets) or endurance exercise (treadmill at 25 m min(-1) for 60 min). Rats were killed immediately or 1, 3, 6, or 24 h after completion of the resistance or endurance exercise, and gastrocnemius muscles were removed. Non-exercise control animals were killed in a basal state (control group). Intramuscular VDR expression was significantly higher immediately after resistance exercise and elevated for 3 h after exercise compared with the control group (P < 0.05), and the resistance exercise significantly increased phosphorylated ERK1/2 and Mnk1 expression (P < 0.05), which may be associated with VDR expression, immediately after exercise. Additionally, intramuscular cytochrome P450 27B1 expression, an enzyme related to vitamin D metabolism, was significantly higher at 1 and 3 h after exercise (P < 0.05) compared with the control group. In contrast, endurance exercise had no effect on any of the measured proteins. Our results indicate that resistance exercise may be an efficient way to increase intramuscular VDR and related enzyme expression. This article is protected by copyright. All rights reserved.