Effects of Bacterial Endotoxins on Metabolism

Abstract

Endotoxins can be assayed on the basis of their toxicity for experimental animals, their pyrogenicity, their ability to necrotize tumors, and their antigenicity. Another property, observed in the course of recent experiments, makes possible a new assay. The initial observation on which the assay is based was obtained when an intraperitoneal injection of appropriate numbers of heatkilled cells of Salmonella typhimurium was found to prevent completely the elevation in urinary nitrogen excreted by mice given adrenocorticotropic hormone (ACTH) subcutaneously (1). The same number of heat-killed cells had no apparent effect on the total protein catabolized in response to concurrently injected cortisone as judged by the increase in urinary nitrogen eliminated under these conditions. From these observations, endotoxins seem to prevent certain physiological manifestations normally elicited by ACTH but do not influence the metabolic activity of exogenous glycocorticoid. Since there is an inverse proportionality between the quantity of endotoxin injected and the quantity of urinary nitrogen excreted following ACTH administration (2), this relationship has been used to develop the assay. In order to establish the validity of such an assay, endotoxin alone must be shown to produce the effect on which the assay is based. The extent to which such proof is possible is, of course, limited but within these limits the evidence to be presented is convincing. It is also necessary to determine the sensitivity of the assay before its usefulness can be related to other methods. This report is concerned with results obtained with these aims in mind. Method•ndotoadn.--Seven different preparations were used. A saline suspension of a known number of Salmonella typhimur~um, strain SR-11, were killed by pasteurization at 60°C.for 30 minutes. Lack of growth on subculture in brain-heart infusion broth (Difco) was taken as proof of steAlization. Usually the suspension had to be heated a second or third time before no growth was observed. The final material was stored at 5°C. in sealed vials. The dry weight of three different preparations was found to be about 8/~ mg. per 109 heat-killed cells. Comparatively crude endotoxin was derived as acetone and ether-extracted cells of

Effects of Bacterial Endotoxins on Metabolism

“…Endotoxins.--As in previous reports (8,9), the standard material employed as endotoxin is a saline suspension of heat-killed (pasteurized) Salmonella typhimurium, strain SR-11. A sutticient quantity of material for several months of work is prepared, dispensed in sealed tubes in 10 ml portions, and stored at 5°C until ready for use.…”

“…Irrcversibility of Endointoxication.--It has been found that cortisone (and other glycocorticoids) have prophylactic value against endotoxin but are unable to protect against lethality after a delay of a few hours (9). Endointoxi-cation appears to be irreversible, therefore, as far as cortisone is concerned.…”

The Implication of Tryptophan Pyrrolase in Endotoxin Poisoning

“…It has been found that cortisone (and other glycocorticoids) has prophylactic value against endotoxin but is unable to protect against lethality after a delay of a few hours (Berry and Smythe, 1961). Endointoxication appears to be irreversible, therefore, as far as cortisone is concerned.…”

Effects of Bacterial Endotoxins on Metabolism

“…(Received for publication, July 19, 1961) An injection of either heat-killed Salmonella typMmurium or the lipopolysaccharide from any one of several different Gram-negative bacteria prevents or lowers, depending upon dosage, the increase in urinary nitrogen excreted by mice in response to an injection of adrenocorticotrophic hormone (ACTH) (1). All available evidence points to the fact that endotoxin is responsible for this effect and that the quantity required is inversely proportional to the toxicity of the specific preparation employed.…”

“…The particular material employed had an LD60 of 1.5 mg when injected intraperitoneally into 20 gm mice (1). In some cases a purified lipopolysaccharide derived from Escherichia coli was employed.…”