Changes in the Activities of Enzymes, Especially Lactate Dehydrogenase, in Endotoxin‐Poisoned Mice

Self Cite

The present study was conducted by the use of purified glucocorticoid antagonizing factor (GAF) released in blood of endotoxemic mice to determine whether or not the factor (GAF and Ca2+) may play a possible role of mediator in depletion mechanism of liver glycogen in endotoxemia.The liver glycogen level in 2 hr after injection with GAF plus cortisone-treated mice was markedly lower than that in cortisone alone-treated mice. However, the administration of trifluoperazine or verapamil markedly increased glycogen levels in liver of GAF plus cortisone-injected mice. On the other hand, when the mice fed a calcium-free diet were injected with GAF plus cortisone, there was merely a significant difference in liver glycogen level as compared to cortisone alone-treated mice. The level of Ca2+ in liver cytosol fraction in cortisone-treated mice was higher 2 hr after GAF injection than that in the cortisone alone-treated one. The phosphorylase a activity in liver 2 hr after injection of GAF plus cortisone did not show a significant difference as compared to that in mice treated with cortisone alone.However, the activity ratio of glycogen synthase enzyme (synthase I/synthase I + D) was decreased in GAF plus cortisone-treated mice as compared to that in cortisone alone-treated mice. These findings suggest that there are participations of Ca2+ and mediator GAF released from reticuloendothelial system (RES) macrophages in glucoregulation of endotoxemia.Thus, it may be speculated that intracellular Ca2+ may mediate glycogenesis rather than glycogenolysis in the depletion mechanism of liver glycogen during GAF-poisoning.From many investigations it is well known that endotoxin depresses both in vivo gluconeogenesis and glycogenesis in the liver (4, 5). Berry and his colleagues (11) demonstrated that endotoxin-poisoned mice produced a glucecorticoid antagonizing factor (GAF) which inhibits the gluconeogenesis and glycogenesis stimulated by cortisone administration, and that zymosan-treated mice showed higher GAF titers in serum than normal mice after endotoxin challenge.In our previous report (21), we attempted to purify the humoral mediator (GAF) released in serum from zymosan-primed mice 2 hr after endotoxin administration. The purified GAF showed a single band in electrophoresis in SDS-polyacrylamide gel. The 985

“…This finding coincided with reports observed by many workers on liver phosphorylase activity during endotoxicosis (1,19).…”

Section: Effect Of Administration Of Calcium Antagonist and Calmodulisupporting

confidence: 81%

“…From many investigations it is well known that endotoxin-poisoned animals initially exhibit hyperglycemia, which is followed by a prompt fall in blood sugar to a hypoglycemia state with a concomitant decrease in the liver and muscular glycogen levels producing profound lactacidemia (1,10,19).…”

Section: Discussionmentioning

confidence: 99%

Participation of Calcium Ion on Depletion Mechanism of Liver Glycogen by Purified Glucocorticoid Antagonizing Factor Released in Blood during Endotoxemia

Sakaguchi¹,

Ibata²,

Yokota³

1990

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“…In the previous study (41), mice injected with endotoxin exhibited a leakage of the isozymes LDH-3 and LDH-5. Figure 4 shows the electrophoretic scanograms of serum LDH isozyrnes of mice in the present study.…”

Section: Serum Ldh Isozyme Electrophoretic Patterns and Acp Actioiiy mentioning

confidence: 77%

Effect of α‐Tocopherol on Endotoxicosis

Sakaguchi

Kanda

Sakaguchi

et al. 1981

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The effect of a-tocopherol in endotoxicosis was studied. The a-tocopherol level significantly decreased in mouse liver 18 hr after endotoxin administration, thereafter tending to increase to approach the normal range. In endotoxin-tolerant mouse liver, the lipid peroxide level was reduced to less than half of that in nontolerant animals following endotoxin challenge. The liver lipid peroxide level and serum lactate dehydrogenase or acid phosphatase leakage were studied in mice fed a vitamin E-deficient (ED) diet and a vitamin E-supplemented (ES) diet for 40 days. ED mouse liver exhibited a higher formation of lipid peroxide after endotoxin was given while there was a markedly lower level in ES mouse liver. There was significantly more serum lactate dehydrogenase or acid phosphatase leakage in ED mice than in ES mice after endotoxin administration. There was about a 25% decrease in liver superoxide dismutase (SOD) activity in endotoxin-poisoned mice fed both the normal and the ED diets, while the activity was at a higher level in ES-fed mice. These results suggest that atocopherol may be helpful in preventing membrane instability in endotoxin poisoning.In the previous paper (42), we reported that administration of Salmonella endotoxin resulted in marked formation of lipid peroxide in mouse liver compared to that in the fasting controls. On the other hand, the activities of superoxide dismutase and glutathione peroxidase, which are the scavengers of free radicals, decreased in mouse liver 18 hr postintoxication. The lipid peroxide level in endotoxinpoisoned mice given a-tocopherol, the most important form of vitamin E, was lower than that in the controls. Furthermore, it was found that a-tocopherol prevents completely the membrane protein damage which arises from endotoxin challenge.Most, if not all, of the biologically functional a-tocopherol is associated with the membranous portions of cells. Many investigators have shown that a-tocopherol plays an important antioxidant role by blocking the peroxidation of polyunsaturated fatty acid (PUFA) in biomembranes (31,43,50). Lucy proposed that a-tocopherol is intimately associated with the hydrocarbon portion of PUFAs of membranes, and may play a physicochemical role in the stabilization of biological membranes (12,26). Cook et al (9) observed that PUFA-deficient rats were significantly more resistant to bacterial endotoxic shock than normal rats, 787

“…In the previous study (18), mice injected with endotoxin exhibited a leakage of the isozyme LDH-3 and -5 on electrophoretic patterns. Figure 1 shows serum LDH isozyme electrophoretic scanograms.…”

Section: Resultsmentioning

confidence: 99%

Effect of Calcium Ion on Lipid Peroxide Formation in Endotoxemic Mice

Sakaguchi¹,

Ibata²,

Yokota³

1989

Self Cite

The present study was conducted to determine the possible role of intracellular Ca2+ in lipid peroxide formation in endotoxin‐poisoned mice. Leakages of LDH isozyme and acid phosphatase in serum of mice fed a Ca2+‐deficient diet were remarkably increased after administration of 200 μg of endotoxin compared to that in endotoxin‐nontreated Ca2+‐deficient mice. Superoxide anion generation in liver of Ca2+‐deficient mice and in mice fed a normal diet greatly increased after endotoxin administration. On the contrary, after endotoxin injection there was scarcely any difference in SOD activity of liver of Ca2+‐deficient mice as compared to that in endotoxin‐nontreated Ca2+‐deficient mice. In spite of an increase of superoxide anion generation there was little or no effect of endotoxin administration on lipid peroxide formation in mice given a Ca2+‐deficient diet. In the mice treated with a Ca2+‐deficient diet, free radical scavenger levels (α‐tocopherol and nonprotein sulfhydryl) in liver tissue after endotoxin injection were markedly decreased compared to those in Ca2+‐deficient diet alone. Mice fed a normal diet exhibited a significant decrease of lipid peroxide level in liver by injection of endotoxin together with verapamil (10 mg/kg, s.c.). When mice fed a normal diet were injected with endotoxin, the state 3 respiratory activity showed a 49% decrease, and respiratory control ratio (RCR) of endotoxemic mice liver mitochondria was 38% lower than normal liver mitochondria. No difference could be observed in levels of state 3 and RCR between the mice given verapamil plus endotoxin and the normal mice. These findings suggest the possibility that Ca2+ may participate in the free radical formation in the liver during endotoxemia and also that Ca2+ may play an important role in the damage of liver mitochondrial function in endotoxemic mice.