Various nutritional supplements (herbs, vitamins, and micronutrients) improve responses and adaptations to exercise in aged. This study determined the effects of glutamine supplementation on the secretory apparatus of aged Wistar rats submitted to resistance training. Wistar male rats, with fifteen-mo-old were assigned to two groups (n = 8): resistance trained (RT) and resistance trained supplemented with glutamine (RTG). The exercise protocol was performed on a 1.1m vertical (80° incline) ladder with weights tied to the tail for 12 weeks. Body weight and systolic blood pressure was determined at the time of the sacrifice (18 mo of age). Fragments of the right atrium myocardium were studied by electron microscopy and morphometry. The density and size of secretory granules were estimated. The number of pores per 10 µm of nuclear membrane and the relative volume of euchromatin and of Golgi complex and mitochondria were evaluated. No significant differences in systolic blood pressure were observed between the groups. The number of NP granules was 41% greater in RTG group than in the RT group (P < 0.01). There was no significant difference in the areas of the granules among the groups (P > 0.05). Furthermore, there was an increase in the relative volume of euchromatin, a higher density of nuclear pores, and higher relative volumes of Golgi complex and mitochondria in the RTG rats compared with the RT rats. These findings suggest a pool with a high turnover rate, i.e., high synthesis and elimination of NPs. It was concluded that glutamine supplementation caused hypertrophy of the secretory apparatus in right atrium cardiomyocytes that could explain the greater synthesis of NPs in aged resistance trained rats.
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