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Previous Volume 293:681-684 October 2, 1975 Number 14 Next

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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 131l uptake, serum thyroxine, tri-iodothyronine, and thyrotropin concentrations, and the response to thyrotropin-releasing hormone. During exogenous hormone administration, 131l 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 (less than 1.2 muU per milliliter) and a normal 131l uptake usually occurred concurrently in two to three weeks. Serum thyroxine concentration returned to normal at least four weeks after hormone withdrawal.

This article has been cited by other articles:

• Serhal, D. I., Nasrallah, M. P., Arafah, B. M. (2004). Rapid Rise in Serum Thyrotropin Concentrations after Thyroidectomy or Withdrawal of Suppressive Thyroxine Therapy in Preparation for Radioactive Iodine Administration to Patients with Differentiated Thyroid Cancer. J. Clin. Endocrinol. Metab. 89: 3285-3289 [Abstract] [Full Text]