The Journal of clinical endocrinology and metabolism
-
J. Clin. Endocrinol. Metab. · Nov 1984
Protein metabolism in skeletal muscle tissue from hyperthyroid patients after preoperative treatment with antithyroid drug or selective beta-blocking agent. Results from a prospective, randomized study.
Protein metabolism in skeletal muscle tissue was studied in three groups of patients undergoing thyroid surgery: group I (n = 8), hyperthyroid patients preoperatively treated with an antithyroid drug and T4; group II (n = 8), hyperthyroid patients preoperatively treated with the beta 1-selective adrenoreceptor blocking agent metoprolol; group III (n = 5), euthyroid patients operated on for nodular goiter or adenoma. The study was prospective and hyperthyroid patients were randomly allocated to one of the two preoperative regimens. During operation a biopsy was taken from the sternohyoid muscle and rates of protein synthesis and degradation were measured in incubated muscle tissue. ⋯ Protein synthesis rates were similar in the three groups of patients. This study demonstrated for the first time increased proteolysis in skeletal muscle tissue from patients with high serum T3 concentrations. The results indicate that changes of skeletal muscle protein metabolism in hyperthyroid patients are not normalized by beta 1-blockade despite the fact that this treatment effectively controlled symptoms and signs of hyperthyroidism.