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991.
No evidence for expression of the insulin-regulatable glucose transporter in endothelial cells 总被引:6,自引:0,他引:6
A major effect of insulin is to increase glucose transport in muscle and fat. A family of genes encoding distinct mammalian glucose transporters has recently been elucidated. One of these, the insulin-regulatable glucose transporter (IRGT), is primarily expressed in muscle and fat, tissues that exhibit insulin-dependent glucose transport. Insulin promotes glucose transport in these tissues by stimulating movement of the glucose transporter from an intracellular location to the plasma membrane. Recent studies, however, suggest that an additional effect of insulin in these tissues may be the facilitation of glucose transport, presumably across capillary endothelium. This hypothesis is based on the localization of the IRGT in endothelial cells specific to muscle and adipose tissue. We report here, however, on morphological and biochemical studies using several different IRGT-specific antibodies in which we could not reproduce these results. 相似文献
992.
J E Damber 《Experientia》1990,46(5):486-487
Testicular blood flow was measured by means of Xenon-133 clearance in control rats and rats treated with guanethidine for 3 weeks. Plasma and testis testosterone concentrations were also measured, and the effect of hCG-treatment was examined. No difference in testicular blood flow between the control group and the guanethidine-treated group was found. However, in guanethidine-treated rats, plasma and testis testosterone concentrations after hCG-treatment were significantly decreased. The results may indicate that adrenergic nerves are involved in the regulation of Leydig cell function. 相似文献
993.
Summary Poison oak urushiol, a mixture of 3-alk(en)ylcatechol derivatives was found to mediate DNA strand scission in the presence of oxygen and with copper(II) chloride as a catalyst. The reactionis believed to occur via activated reduced oxygen produced during oxidation of the catechol into itso-quinone derivative. 相似文献
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New data on excisions of Mu from E. coli MCS2 cast doubt on directed mutation hypothesis 总被引:12,自引:0,他引:12
According to the directed mutation hypothesis, certain mutations in bacteria occur more frequently in environments in which the resulting phenotype is selectively favoured than in non-selective environments. This hypothesis therefore challenges the fundamental tenet that mutations occur spontaneously, irrespective of effects on the organism's fitness. One purported case of directed mutation is the excision of a Mu sequence from Escherichia coli strain MCS2 in minimal lactose-arabinose medium. Here, we show that this case can be more simply explained by an accelerated rate of excision mutation in response to non-specific physiological stresses of starvation and by slight growth of MCS2 on minimal lactose-arabinose medium. 相似文献