Metabolism of 5-thio-D-glucopyranose and 6-thio-D-fructopyranose in rats

Synthesis and structural analysis of 6-deoxy-6-hydroxyphosphinyl-d-fructopyranose derivatives

3,4-Di-O-benzyl-6-deoxy-6-diethoxyphosphinyl-1,2-O-isopropylidene-beta-D-fructofuranose (13) was prepared from the known 1,2-O-isopropylidene-6-O-tosyl-beta-D-fructofuranose in five steps. Reduction of 13 with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of hydrochloric acid and then hydrogen peroxide, afforded the 6-deoxy-6-hydroxyphosphinyl-D-fructopyranose derivative. This was converted into the 1,2,3,4,5-penta-O-acetyl-6-deoxy-6-methoxyphosphinyl-D-fructopyranoses, whose structure and conformation were established by 1H NMR spectroscopy.

Stereoselectivity in deoxygenation of 5-hydroxy-5-phosphinyl-hexofuranoses (alpha-hydroxyphosphonates)

The addition of dimethyl phosphonate to six different hexofuranos-5-uloses in the presence of DBU, followed by esterification with methoxalyl chloride and then radical reduction, afforded 5-deoxy-5-dimethoxyphosphinyl-D- and L-hexofuranoses. The stereoselectivity of the deoxygenation and possible transition-state models are discussed.

Effect of 5-thio-D-glucose on testosterone biosynthesis in vivo in mice testes

Testicular synthesis of (14C)cholesterol and (14C)testosterone from (14C)acetate were investigated in mice treated with 5-thio-D-glucose at a dose of 33 mg/kg body weight/day for 21 days. The testicular synthesis of free cholesterol as well as steroids were significantly decreased. The steroid synthesizing enzymes, cholesterol esterase, cholesterol side-chain cleaving enzyme, total alpha-hydroxysteroid dehydrogenase and total beta-hydroxysteroid dehydrogenase, were also analysed. Cholesterol esterase and total beta-hydroxysteroid dehydrogenase were significantly reduced whereas total alpha-hydroxysteroid dehydrogenase was unaffected. Hence, a decrease in free cholesterol for steroid synthesis and a decreased activity of the steroidogenic enzyme, beta-hydroxysteroid dehydrogenase, were responsible for the diminished synthesis of testosterone.

Glucose concentration and insulin release in 5-thio-D-glucose-treated mice

Male albino mice were given a single dose of various concentrations (25, 50, and 100 mg/kg body weight) of 5-thio-D-glucose or daily infusions (33 mg/kg body weight) of 5-thio-D-glucose for 21 days. Elevated blood glucose and immunoreactive insulin (IRI) levels were observed in the mice treated with 5-thio-D-glucose. Fasting glucose levels reached a maximum in 30 minutes and IRI levels reached a maximum in 60 to 90 minutes in the single-dose treated animals compared to preintubation levels. In the mice treated for 21 days, the fasting and fed glucose and IRI levels were significantly increased. Single dose of glucose (1 g/kg body weight) given to fasting and fed mice did not alter the glucose and IRI levels in the treated animals. However, a single dose of 5-thio-D-glucose (33 mg/kg body weight) given to fasting and fed treated animals increased the IRI levels significantly but not the glucose concentration. These data show that both single-dose and 3-week treatment with 5-thio-D-glucose produced a hyperinsulinemic diabetes in male albino mice.

The male antifertility agents alpha chlorohydrin, 5-thio-D-glucose, and 6-chloro-6-deoxy-D-glucose interfere with sugar transport across the epithelium of the rat caput epididymidis

The effects of the male antifertility agents alpha-chlorohydrin, 5-thio-D-glucose, and 6-chloro-6-deoxy-D-glucose on sugar transport (3H-3-O-methyl-D-glucose and 3H-2-deoxy-D-glucose) across the rat caput epithelium was studied in vivo and in vitro. The compound alpha-chlorohydrin reduced sugar transport uptake in vivo but not in vitro, whereas 5-thio-D-glucose and 6-chloro-6-deoxy-D-glucose were both effective in vivo and in vitro. The mechanism of action of these compounds on sugar movement across the caput epithelium is probably complex. Direct competition for the glucose carrier situated on the basolateral membrane and intratubular effects are suggested. Thirty-day injections of 5-thio-D-glucose or alpha-chlorohydrin did not have adverse effects on sugar transport or the permeability of the blood-testis and blood-epididymis barriers as assessed by an in vitro technique.

Effect of 5-thio-D-glucose on testicular lipids of mice

Spermatogenesis is reported to be completely inhibited by 5-thio-D-glucose in mice. In an investigation of this inhibition, testicular lipid constituents, namely, total lipids, phospholipids, triacylglycerol, free and total cholesterol, 3-hydroxy-3-methylglutaryl-coenzyme A reductase and NADPH generators like glucose-6-phosphate dehydrogenase, isocitrate dehyrogenase and malic enzyme were estimated in mice fed with 5-thio-D-glucose (33 mg/kg) by gastric intubation for 21 days. Significant increase in cholesteryl ester, glucose-6-phosphate dehydrogenase activity and malic enzyme and a decrease in free cholesterol and phospholipids were observed.

Potential of 5-thio-D-glucose as an agent for controlling male fertility

This paper reviews experimental work bearing on the feasibility of using the analog of glucose, 5-thio-D-glucose, to control human male fertility. The initial experiments in mice indicated that suitable oral doses of thioglucose caused reversible infertility unaccompanied by loss of libido or evidence of extratesticular toxicity. Subsequent work in mice and rats showed that treatment of 7 or 8 weeks appeared to cause irreversible sterility in many of the animals. In both species the smallest doses causing infertility also caused transient hyperglycemia. In rats a large dose of thioglucose was found to raise the concentration of nonesterified fatty acids in the blood and repeated smaller doses increased the excretion of catecholamines. These reports, suggesting that it can cause sterility and has extratesticular effects on metabolism, do not augur well for the acceptibility of thioglucose as a suitable chemical with which to control fertility in the human male.