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THE PRESENCE OF ENDOGENOUS PYROGEN IN NORMAL RABBIT TISSUES
The Journal of Experimental Medicine
|June 1, 1965
Summary
Rabbit tissue extracts can cause fever, suggesting an endogenous pyrogen. This fever-inducing substance is likely a large molecule, distinct from bacterial endotoxins or white blood cells, and found widely in tissues.
Area of Science:
- Physiology
- Immunology
- Biochemistry
Background:
- Fever is a common physiological response.
- Pyrogens are substances that induce fever.
- The origin of endogenous pyrogens has been debated.
Purpose of the Study:
- To investigate the pyrogenic potential of saline extracts from uninfected rabbit tissues.
- To determine the source and characteristics of tissue-derived pyrogens.
- To differentiate tissue pyrogen from known pyrogenic agents like bacterial endotoxins.
Main Methods:
- Intravenous injection of saline tissue extracts into rabbits.
- Observation and comparison of febrile responses.
- Analysis of pyrogen resistance to acid and alkali treatment.
Main Results:
- Tissue extracts from muscle, lung, heart, spleen, liver, and kidney induced fever in rabbits.
- Different tissues produced fevers of varying duration and intensity.
- The minimal pyrogenic dose was estimated between 1.5 and 3 gm of wet tissue weight.
- Evidence excluded bacterial endotoxins and polymorphonuclear leukocytes as the source.
- Tissue pyrogen was identified as a large molecule, resistant to acid but sensitive to alkali.
Conclusions:
- A pyrogenic material of endogenous origin is widely distributed in rabbit tissues.
- This endogenous tissue pyrogen is distinct from bacterial endotoxins and leukocytes.
- The molecular characteristics suggest a novel pyrogenic agent with potential pathological roles.