The characteristics and site of inhibition of gluconeogenesis by endotoxin were investigated in liver cells isolated from control and endotoxin-treated rats. Endotoxin treatment was associated with inhibition (40-50%) of gluconeogenesis from lactate plus pyruvate over a range of concentrations of substrate and of oleate and with or without glucose or glucagon. Similar inhibition was observed with asparagine, proline, glutamine, alanine and a substrate mixture, but not with glycerol, glyceraldehyde, dihydroxyacetone or endogenous substrates. There was no change in cellular ATP content or in the rates of ketogenesis or ureogenesis from asparagine, proline or glutamine. Other effects on isotopic fluxes, metabolite contents, enzyme activities and control coefficients were consistent with the suggestion that the effects of endotoxin on gluconeogenesis are exerted at the level of phosphofructokinase-1, and not at phosphoenolpyruvate carboxykinase, pyruvate kinase, pyruvate carboxylase or glucokinase.
SummaryModification of the carbohydrate structures of recombinant tissue-type plasminogen activator (rt-PA) can increase or decrease its rate of clearance in rabbits. When rt-PA was treated with sodium periodate to oxidize carbohydrate residues, the rate of clearance was decreased from 9.6 ± 1.9 ml min−1 kg−1 to 3.5 ± 0.6 ml min−1 kg−1 (mean ± SD, n = 5). A similar change in the clearance of rt-PA was introduced by the use of endo-β-N-acetyl- glucosaminidase H (Endo-H), which selectively removes high mannose asparagine-linked oligosaccharides; the clearance of Endo-H-treated rt-PA was 5.0 ± 0.5 ml min−1 kg−1. A mutant of rt-PA was produced with an amino acid substitution at position 117 (Asn replaced with Gin) to remove a potential glycosylation site that normally contains a high mannose structure. The clearance of this material was also decreased, similar to the periodate and Endo-H-treated rt-PA. Conversely, when rt-PA was produced in the CHO 15B cell line, which can produce only high mannose oligosaccharide structures on glycoproteins, the clearance was increased by a factor of 1.8. These results demonstrate that the removal of rt-PA from the blood depends significantly upon the nature of its oligosaccharide structures.
Alcoholic injury can alter the hormonal signaling pathway and lead to glucose and lipid metabolism disorders. In this study, we investigated whether the strength training could exert protective effects against the alterations caused by ethanol consumption on prostatic metabolism. A UChB, ethanol‐preferring rats were used in this study. Strength training was conducted for 3 days per week for 13 weeks, rats performed jumps in water carrying a weight load strapped to their chests as part of a strength training protocol. The reduced alcohol consumption by strength training was accompanied by increased glucose, serum lipid profile, total protein levels, and reduced hormonal levels. The results of protein expression of prostatic tissues in the ethanol‐ and strength training‐treated groups indicated that “steroidal hormone receptors,” “fatty acid translocation,” and “cell regulation” were significantly different between ethanol‐ and strength training‐treated groups. Taken together, these findings show that strength training effectively ameliorated prostatic injuries in alcoholic rats at least partially by acting on lipids receptors and steroidal hormone receptors pathway, suggesting the strength training as a potential novel therapeutic strategy for treating prostate injuries caused by ethanol.
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