Sulfate conjugates animals

The absorption of spectinomycin is poor via the oral route, but rapid and extensive after intramuscular injection. It is not extensively metabolized in animals and rapidly excreted in the urine (16). Following subcutaneous injections of spectinomycin sulfate to cattle, 70-83% of the dose was excreted in the urine and 62-64% of this was parent spectinomycin (17). Several minor metabolites were found in the urine that consisted mostly of dihydroxyspectinomycin and two acetylated isomers, and an unusual ammoniated spectinomycin metabolite and its acetylated derivative. There was also some evidence, but it was not compelling, for a spectinomycin sulfate conjugate. Dihydrospectinomycin and parent spectinomycin were the only identifiable major components found in the liver and the kidney, respectively. Liver and kidney retained the highest concentrations of total residues throughout the 15-day withdrawal period. 

Animals. Rapidly absorbed, extensively metabolised and rapidly excreted. No evidence of accumulation, even on repeated dosing. Metabolism proceeds by oxidation to phenolic derivatives which are excreted as glucuronide or sulfate conjugates Plants. Little metabolism occurs in fruit Soil. Rapid degradation, DT50 7-54 days. Low potential for leaching... 

Animals. 98.5-100% of 14C was excreted within 7 days. The major metabolic routes were deethylation of the 4-ethoxy group, cleavage of the carbamate linkage, acetylation, and finally formation of the glucuronide and sulfate conjugates... 

PCB arene oxides can also generate dihydrodiols via a hydrolytic pathway mediated by microsomal epoxide hydrolase, although metabolism to monohydroxy-metabolites is more commonly observed [74,75]. OH-PCBs are susceptible to further metabolism, i. e. conjugation reaction with glucuronic acid or sulfate, which increases the water solubility and facilitates excretion. Glucuronic acid and sulfate conjugates of several PCB congeners have been determined in bile and urine from experimental animals exposed to the PCBs [50,76,77]. Biliary excretion is the preferred pathway for PCB metabolites, whereas only a small portion is excreted via the urine [77]. 

Pentachlorobenzene can be absorbed readily through gastrointestinal and respiratory tracts in humans and experimental animals. Chlorobenzenes accumulate primarily in fatty tissues and have been shown to cross the placenta. Pentachlorobenzene is metabolized via cytochrome P450-dependent processes to its major metabolites pentachlorophenol and 2,3,4,6-tetrachlorophenol. Food restriction was reported to increase its metabolism. Metabolites are excreted in the urine as mercapturic acids, glucuronic acid, or sulfate conjugates. Some proportion of the chemical is eliminated unchanged in the feces. 

Conjugation of 0-, N- and S-contalnlng functional groups with sulfate Is very common In animal systems. Sulfate Is transferred from adenosine 3 -phosphate-5 -sulfatophosphate (PAPS) by a variety of transfer enzymes. The mechanisms for sulfation of xenobiotics (74,75) and the chemistry of sulfate esters and related compounds and the synthesis of these have been reviewed (75-77). Syntheses of 0-, N- and S-sulfate conjugates of xenobiotics may be carried out by the methods described below. 

Acetaminophen administered to animals is excreted mainly as its glucuronide and its sulfate conjugate ( ), but a small amount of the drug is excreted as its mercapturic acid and cysteine derivatives in all animals studied including man (16) (Fig.2). 

After these in vivo and in situ experiments in animals, the absorption of resveratrol by humans was performed. Soleas et al. [120] was the first to measure free and conjugated resveratrol in plasma and urine. Volunteers were given 25 mg of resveratrol orally in 120 mL of white wine. The plasma concentrations of free resveratrol and glucuronide and sulfate conjugates peaked at 30 min. At this time, the concentration of resveratrol conjugates was 48-fold higher than the free resveratrol (338 pg vs. 7.1 pg L ). Over the 24-h collection period, 24.6% of the resveratrol was recovered in the urine, predominantly in conjugated form. Walle et al. evaluated the absorption after oral administration of 25 mg of C-labeled resveratrol [121]. They determined a peak plasma resveratrol equivalent concentration, based on total radioactivity, of 491 pg at 1 h after the dose. 

In terrestrial animals, the excreted products of PAHs are mainly conjugates formed from oxidative metabolites. These include glutathione conjugates of epoxides, and sulfate and glucuronide conjugates of phenols and diols. 

After exerting their action in the organism, natural and synthetic hormones are catabolized in the liver by conjugation to glucuronide and/or sulfate moieties, forming more polar conjugated forms which are excreted via urine. This is the main route of hormone excretion in humans and pigs. A fraction of hormones is also excreted in a free form via feces in animals such as sheep and cattle this is the main route for hormone excretion (Table 3) [66, 67],... 

---