Usage Information

Intracellular conversion of thyroxine to triiodothyronine is required for the optimal thermogenic function of brown adipose tissue.
A C Bianco, J E Silva
A C Bianco, J E Silva
Published January 1, 1987
Citation Information: J Clin Invest. 1987;79(1):295-300. https://doi.org/10.1172/JCI112798.
View: Text | PDF | Correction
Research Article

Intracellular conversion of thyroxine to triiodothyronine is required for the optimal thermogenic function of brown adipose tissue.

Abstract

The effect of thyroxine (T4) and triiodothyronine (T3) on the expression of uncoupling protein (UCP) in rat brown adipose tissue (BAT) has been examined. Thyroidectomized rats have a threefold reduction in basal UCP levels. When exposed to cold, they become hypothermic and show a fivefold lower response of UCP than euthyroid controls. T3 augments the basal levels and the response of UCP and its mRNA to cold in a dose-dependent manner. However, to normalize the response of UCP, T3 has to be given in a dosage that produces systemic hyperthyroidism. Mere T3 replacement corrects the systemic hypothyroidism but not the hypothermia or the low levels of UCP. In contrast, replacement doses of T4 prevent the hypothermia and correct the UCP level. Both effects of T4 are blocked by preventing T4 to T3 conversion in BAT. Thus, the optimal UCP response to cold and protection against hypothermia require a high BAT T3 concentration, which is attained from euthyroid levels of T4 via the activation of the BAT T4 5'deiodinase during cold exposure, but not from euthyroid plasma T3 levels.

Authors

A C Bianco, J E Silva

×

Usage data is cumulative from July 2024 through July 2025.

Usage JCI PMC
Text version 586 35
PDF 149 18
Figure 0 4
Scanned page 420 3
Citation downloads 100 0
Totals 1,255 60
Total Views 1,315
(Click and drag on plot area to zoom in. Click legend items above to toggle)

Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.

Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.

Advertisement