Sorbitol dehydrogenase and

This MRL was calculated using a NOAEL of 1 mg/kg/day, based on the absence of detected adverse hepatic effects (Bruckner et al. 1986). Male Sprague-Dawley rats were exposed to 0, 1, 10 or 33 mg/kg/day, 5 days/weeks, for 12 weeks, by corn oil gavage. Slightly elevated blood levels of of sorbitol dehydrogenase and centrilobular vacuolation of the liver were observed at a LOAEL of 10 mg/kg/day, but not at 1 mg/kg/day. To accound for the study s intermittent exposure (5 days/week), the MRL was derived using an adjusted NOAEL of 0.71 mg/kg/day. Similar NOAEL and LOAEL values have been described for related hepatic effects in mice after exposure by gavage (Condie et al. 1986 Hayes et al. 1986). 

The involvement of testosterone in the testicular atrophy caused by di(2-ethyl-hexyl) phthalate was examined by co-administration of testosterone (1 mg/kg bw) subcutaneously with 2000 mg/kg bw di(2-ethylhexyl) phthalate [purity not specified] in groundnut oil to adult male Wistar rats for 15 days (Parmar et al., 1987). Administration of di(2-ethylhexyl) phthalate reduced the sperm count and also significantly increased the activity of y-GT, lactate dehydrogenase and P-glucuronidase and decreased the activity of sorbitol dehydrogenase and acid phosphatase. Co-adminis-tration of testosterone seemed to normalize the sperm count and the activity of testicular enz5mies. The role of testosterone in the testicular toxicity of di(2-ethylhexyl) phthalate has not been fully elucidated. Several reports refer to increased or decreased testosterone levels in plasma and testicular tissue. 

Sorbitol and Mannitol. Sorbitol is present in fruits but not in grapes. A method for its determination is required to detect illegal blending of fruit wines with grape wines. Mannitol is produced by bacterial spoilage. Sorbitol dehydrogenase and thin-layer chromatography have been used for their simultaneous determination (5). 

The bioluminescent determinations of ethanol, sorbitol, L-lactate and oxaloacetate have been performed with coupled enzymatic systems involving the specific suitable enzymes (Figure 5). The ethanol, sorbitol and lactate assays involved the enzymatic oxidation of these substrates with the concomitant reduction of NAD+ in NADH, which is in turn reoxidized by the bioluminescence bacterial system. Thus, the assay of these compounds could be performed in a one-step procedure, in the presence of NAD+ in excess. Conversely, the oxaloacetate measurement involved the simultaneous consumption of NADH by malate dehydrogenase and bacterial oxidoreductase and was therefore conducted in two steps. 

Chronic copper poisoning in domestic sheep is first characterized by a period of passive accumulation of copper in the tissues. This period varies from a few weeks to more than a year. During this time the animal appears outwardly normal although the liver may contain more than 1000 mg Cu/kg DW and plasma activities of aspartate transaminase, sorbitol dehydrogenase, lactic... 

The liver appeared to be a target organ for hexachloroethane following oral administration. When one dose of 500 mg/kg was administered in an olive oil aqueous emulsion to male sheep, the levels of glutamate dehydrogenase, sorbitol dehydrogenase, ornithine carbamyl transferase, and aspartate aminotransferase in serum increased in the 2-day period after compound administration and then normalized (Fowler 1969b). Hexachloroethane had no effect on bromsulphthalein uptake from the blood by liver cells, but the transfer of this dye to bile was reduced in sheep exposed to doses of 500-1,000 mg/kg/day. 

In clinical chemistry however, these systems have not been differentiated as yet. Since the oxidation of an alcohol corresponds to the reduction of a ketose or an aldose, the designations ketose reductase and aldose reductase, respectively, were suggested (H4, W14). In this paper however, the enzyme or enzyme system will be named polyol or sorbitol dehydrogenase (SDH), although the latter expression does not characterize exacdy the enzyme s function in a general biochemical sense. But sorbitol or fructose have been commonly used as substrates in clinical chemical investigations. 

Fic. 8. NAD polyol dehydrogenase in sera of CCl4-poisoned mice sorbitol, ribitol, and mannitol oxidation (pH 9.6 polyols as substrates). 

I.L. Kwee, H. Igarashi, T. Nakada, Aldose reductase and sorbitol dehydrogenase activities in diabetic brain In vivo kinetic studies using F-19 3-FDG NMR in rats, Neuroreport 7 (1996) 726-728. 

Adult male albino rats received 0, 500 or 1000 mg/kg di(2-ethylhexyl) phthalate by gavage for 15 days and were killed 24 h later (Siddiqui Srivastava, 1992). Relative testis weight and epididymal sperm counts were reduced at the highest dose, as was the activity of several enzymes relevant to spermatogenesis (aldose reductase and sorbitol dehydrogenase). The activity of testicular lactate dehydrogenase was increased at this dose. 

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