What question did this study set out to answer?

To determine whether macrophages of the reticuloendothelial system possess the enzymatic machinery to convert hemoglobin-heme into bilirubin.

June 1, 1971The Journal of Experimental MedicineOpen Access

The Enzymatic Degradation of Hemoglobin to Bile Pigments by Macrophages

View Full Paper

Ask AI

Bookmark

To determine whether macrophages of the reticuloendothelial system possess the enzymatic machinery to convert hemoglobin-heme into bilirubin.
Harvested pure populations of macrophages chemically or immunologically from the peritoneal cavity and lungs of rodents.
Assayed macrophage homogenates for microsomal heme-oxygenase activity before and after in vivo exposure to methemalbumin, microcrystalline hemin, or hemoglobin.
Evaluated enzyme activity in granulomatous tissue surrounding subcutaneous hematomas and characterized cofactor requirements.
Unstimulated macrophages lacked detectable heme-oxygenase activity, but in vivo exposure to heme pigments induced substantial activity far exceeding baseline levels in the liver or spleen.
The macrophage enzyme was localized to the microsomal fraction, required molecular oxygen and NADPH, was inhibited by carbon monoxide, and exhibited a Km similar to hepatic and splenic heme-oxygenase.
Substrate disappearance consistently exceeded bilirubin production in standard assays, indicating concurrent alternative degradation routes for heme.

Discussion

No takes yet. Share an insight, caveat, or question.

Implication

Laboratory study demonstrates substrate-induced heme degradation to bilirubin in rodent macrophages, highlighting reticuloendothelial adaptation to red cell breakdown.

Cite This Study

Pimstone et al. (1971) studied this question.

synapsesocial.com/papers/6a7c0f942305edf9bbed34e2 https://doi.org/10.1084/jem.133.6.1264

View Full Paper

Ask AI

Bookmark

Implication

Laboratory study demonstrates substrate-induced heme degradation to bilirubin in rodent macrophages, highlighting reticuloendothelial adaptation to red cell breakdown.

The Enzymatic Degradation of Hemoglobin to Bile Pigments by Macrophages

Key Points

Discussion

Implication

Cite This Study

The Enzymatic Degradation of Hemoglobin to Bile Pigments by Macrophages

Key Points

Discussion

Implication

Cite This Study

Also Consider

Also Consider