Comportamento das reservas de glicogênio no músculo desnervado de ratas tratadas com diferentes doses de estrógeno

Abstract

Objective: To evaluate the action of estrogen on the glycogen profile of denervated skeletal muscle in female rats. Methods: The animals were divided into six experimental groups (n=6): control; denervated for 15 days; denervated and treated with estrogen at a concentration of 20µg/weight/day; denervated and treated with estrogen at a concentration of 40µg/weight/day; denervated and treated with estrogen at a concentration of 80µg/weight/day; and denervated and treated with estrogen at a concentration of 160µg/ weight/ day. The animals were treated with estradiol cypionate for 15 days. The following analyses were carried out: glycogen content of the soleus, white gastrocnemius and red (mixed) gastrocnemius, by means of the phenol-sulfuric acid method as well as body weight and soleus muscle weight. The statistical analysis included ANOVA and the post-hoc Tukey test (p<0.05). Results: The denervation induced a reduction in glycogen content in the soleus and the white and mixed gastrocnemius muscles. In contrast, there was a progressive elevation of glycogen content concomitant with dose elevation in the groups treated with estrogen, thereby reinstating the glycogen reserves. The most effective concentration was 160µg/weight/day, which showed the best chemometabolic responses and least weight loss. Conclusion: These results suggest that estrogen at the concentration of 160 µg/weight/day was the most efficient at minimizing metabolic impairment and that it may be an important pharmacological instrument for physical therapy practice during rehabilitation.

Resistance Training and Glycogen Content in Ovariectomized Rats

“…In animal models, estrogen has been shown to promote lipolysis and increase fatty acid availability, while decreasing the rate of gluconeogenesis and sparing muscle and liver glycogen use [ 6 ] . Estrogen modulates positively the muscle glycogen content in rats [ 37 ] . Thus, under situations of menopause or ovariectomy the concentration of glycogen may be impaired.…”

“…However, the above mentioned studies are targeted on fat metabolism, while the eff ects of ovariectomy associated with resistance exercise on liver and skeletal muscle glycogen content have not been investigated. Severi et al [ 37 ] studied the infl uence of estrogen on muscle glycogen content of denervated rats. The results revealed that estrogen appears to positively modulate the muscle glycogen content in denervated rats.…”