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Peripheral resistance to thyroid hormone in an infant
The Journal of Clinical Endocrinology and Metabolism
|November 1, 1981
Summary
This study investigated thyroid hormone resistance in an infant, finding both pituitary and peripheral insensitivity despite abnormal nuclear T3 binding. Cellular mechanisms underlying this resistance remain unclear.
Area of Science:
- Endocrinology
- Molecular Biology
- Genetics
Background:
- Peripheral resistance to thyroid hormone (PRTH) is a rare syndrome with elevated thyroid hormones and abnormal TSH suppression.
- This study focuses on a 6-month-old infant presenting with clinical euthyroidism despite biochemical evidence of PRTH.
Observation:
- The infant exhibited elevated serum T4, T3, and TSH levels, with an exaggerated TSH response to TRH stimulation.
- High doses of T3 were required to normalize thyroid hormone levels and suppress TSH response to TRH.
- Cultured skin fibroblasts showed altered T3 nuclear binding with an additional low-affinity site.
Findings:
- The infant demonstrated both pituitary and peripheral resistance to thyroid hormone.
- Nuclear T3 binding in fibroblasts was abnormal, suggesting a molecular basis for resistance.
- Despite altered binding, cellular response to T3 (glucose consumption) was preserved.
Implications:
- This case highlights the complex nature of thyroid hormone resistance and its variable presentation.
- Further research is needed to elucidate the precise cellular mechanisms of PRTH.
- Understanding these mechanisms is crucial for accurate diagnosis and potential therapeutic strategies.