The enzymatic deiodination of thyroxine (T4) is thiol dependent. Fasting (72 h) depresses hepatic T4 deiodination and lowers the hepatic content of nonprotein sulfhydryls (NP-SH) and reduced glutathione (GSH). It has been proposed that the fasting effect may be mediated through these alterations in hepatic sulfhydryls. To test the importance of tissue (hepatic) thiol content in the modification of T4 deiodination consequent to dietary manipulation, we examined the sequential deiodination of T4 to 3,5,3′-triiodothyronine (T3) (5′-deiodination) and 3,3′,5-triiodothyronine (reverse T3, rT3) (5-deiodination) in liver homogenates without added thiol from groups of rats fed Purina lab chow (P) (a protein-rich diet), glucose alone (G), or glucose plus cysteine (Gc) for 72 h or fasted (F) for the same period. The initial rate of each reaction was compared to the tissue concentrations of NP-SH and GSH.
Laurence A. Gavin, Francis A. McMahon, M. Moeller
Usage data is cumulative from April 2023 through April 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 122 | 0 |
75 | 8 | |
Scanned page | 75 | 0 |
Citation downloads | 12 | 0 |
Totals | 284 | 8 |
Total Views | 292 |
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.