Dietary creatine monohydrate supplementation increases satellite cell mitotic activity during compensatory hypertrophy

Nutritional status influences muscle growth and athletic performance, but l ittle is known about the effect of nutritional supplements, such as creatin e, on satellite cell mitotic activity. The purpose of this study was to exa mine the effect of oral creatine supplementation on muscle growth, compensa tory hypertrophy, and satellite cell mitotic activity. Compensatory hypertr ophy was induced in the rat plantaris muscle by removing the soleus and gas trocnemius muscles. Immediately following surgery, a group of six Fats was provided with elevated levels of creatine monohydrate in their diet. Anothe r group of six rats was maintained as a non-supplemented control group. Twe lve days following surgery, all rats were implanted with mini-osmotic pumps containing the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) to label mi totically active satellite cells. Four weeks after the initial surgery the rats were killed, plantaris muscles were removed and weighed. Subsequently, BrdU-labeled and non-BrdU-labeled nuclei were identified on enzymatically isolated myofiber segments. Muscle mass and myofiber diameters were larger (P < 0.05) in the muscles that underwent compensatory hypertrophy compared to the control muscles, but there were no differences between muscles from creatine-supplemented and non-creatine-supplemented rats. Similarly, compen satory hypertrophy resulted in an increased (P < 0.05) number of BrdU-label ed myofiber nuclei, but creatine supplementation in combination with compen satory hypertrophy resulted in a higher (P < 0.05) number of BrdU-labeled m yofiber nuclei compared to compensatory hypertrophy without creatine supple mentation. Thus, creatine supplementation in combination with an increased functional load results in increased satellite cell mitotic activity.