Nelson Vergel
Founder, ExcelMale.com
Recovery of Pituitary Thyrotropic Function after Withdrawal of Prolonged Thyroid-Suppression Therapy
Apostolos G. Vagenakis, M.D., Lewis E. Braverman, M.D., Fereidoun Azizi, M.D., Gary I. Portnay, M.D., and Sidney H. Ingbar, M.D.
N Engl J Med 1975; 293:681-684October 2, 1975DOI: 10.1056/NEJM197510022931402
Abstract
The pattern of thyrotropin secretion was analyzed in seven euthyroid women, before and after withdrawal of long-term thyroid hormone, by serial measurements of thyroid uptake, serum thyroxine, tri-iodothyronine, and thyrotropin concentrations, and the response to thyrotropin-releasing hormone. During exogenous hormone administration, uptake was suppressed, and serum thyrotropin concentrations before and after administration of thyrotropin-releasing hormone were undetectable. After withdrawal of exogenous hormone, thyrotropin secretory function was transiently impaired, as indicated by undetectable basal thyrotropin concentrations together with absence of response to thyrotropin-releasing hormone, and subsequently by normal values of basal thyrotropin concentration and normal responses to releasing hormone while serum thyroxine and tri-iodothyronine concentrations were subnormal. Decreased thyrotropin reserve persisted for two to five weeks.
Detectable values of serum thyrotropin ( <1.2 μU per milliliter) and a normal uptake usually occurred concurrently in two to three weeks. Serum thyroxine concentration returned to normal at least four weeks after hormone withdrawal. (N Engl J Med 293:681–684, 1975)
Apostolos G. Vagenakis, M.D., Lewis E. Braverman, M.D., Fereidoun Azizi, M.D., Gary I. Portnay, M.D., and Sidney H. Ingbar, M.D.
N Engl J Med 1975; 293:681-684October 2, 1975DOI: 10.1056/NEJM197510022931402
Abstract
The pattern of thyrotropin secretion was analyzed in seven euthyroid women, before and after withdrawal of long-term thyroid hormone, by serial measurements of thyroid uptake, serum thyroxine, tri-iodothyronine, and thyrotropin concentrations, and the response to thyrotropin-releasing hormone. During exogenous hormone administration, uptake was suppressed, and serum thyrotropin concentrations before and after administration of thyrotropin-releasing hormone were undetectable. After withdrawal of exogenous hormone, thyrotropin secretory function was transiently impaired, as indicated by undetectable basal thyrotropin concentrations together with absence of response to thyrotropin-releasing hormone, and subsequently by normal values of basal thyrotropin concentration and normal responses to releasing hormone while serum thyroxine and tri-iodothyronine concentrations were subnormal. Decreased thyrotropin reserve persisted for two to five weeks.
Detectable values of serum thyrotropin ( <1.2 μU per milliliter) and a normal uptake usually occurred concurrently in two to three weeks. Serum thyroxine concentration returned to normal at least four weeks after hormone withdrawal. (N Engl J Med 293:681–684, 1975)
