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31.
CEACAM1 regulates insulin clearance in liver 总被引:8,自引:0,他引:8
Poy MN Yang Y Rezaei K Fernström MA Lee AD Kido Y Erickson SK Najjar SM 《Nature genetics》2002,30(3):270-276
We hypothesized that insulin stimulates phosphorylation of CEACAM1 which in turn leads to upregulation of receptor-mediated insulin endocytosis and degradation in the hepatocyte. We have generated transgenic mice over-expressing in liver a dominant-negative, phosphorylation-defective S503A-CEACAM1 mutant. Supporting our hypothesis, we found that S503A-CEACAM1 transgenic mice developed hyperinsulinemia resulting from impaired insulin clearance. The hyperinsulinemia caused secondary insulin resistance with impaired glucose tolerance and random, but not fasting, hyperglycemia. Transgenic mice developed visceral adiposity with increased amounts of plasma free fatty acids and plasma and hepatic triglycerides. These findings suggest a mechanism through which insulin signaling regulates insulin sensitivity by modulating hepatic insulin clearance. 相似文献
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The histocompatibility-Y (H-Y) antigen is a minor histocompatibility antigen which has been detected on cell surfaces from the heterogametic sexes of mammalian, bird, amphibian, teleost and invertebrate species. H-Y is thought to be a male-determining substance in mammals because of its almost perfect correlation with maleness among a variety of mammalian species. To characterize the molecular determinant responsible for H-Y specific serological activity, H-Y positive immunoabsorbent cells were first subjected to various treatments which alter protein or carbohydrate structure and then tested for their ability to absorb H-Y antisera. We present here evidence that the serological determinant of H-Y antigen is carbohydrate. 相似文献
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Regional variations were found in cAMP levels in flash frozen mouse brains with the pons and cerebellum having higher levels than the cerebrum. There were also strain variations with CBA/J and BALB/cJ having higher levels than C57B1/6J in the pons and cerebellum. 相似文献
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Deletion mapping of the t complex of chromosome 17 of the mouse 总被引:3,自引:0,他引:3
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A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin 总被引:3,自引:0,他引:3
Recent fossil discoveries have substantially reduced the morphological gap between non-avian and avian dinosaurs, yet avians
including Archaeopteryx differ from non-avian theropods in their limb proportions. In particular, avians have proportionally longer and more robust
forelimbs that are capable of supporting a large aerodynamic surface. Here we report on a new maniraptoran dinosaur, Anchiornis huxleyi gen. et sp. nov., based on a specimen collected from lacustrine deposits of uncertain age in western Liaoning, China. With
an estimated mass of 110 grams, Anchiornis is the smallest known non-avian theropod dinosaur. It exhibits some wrist features indicative of high mobility, presaging
the wing-folding mechanisms seen in more derived birds and suggesting rapid evolution of the carpus. Otherwise, Anchiornis is intermediate in general morphology between non-avian and avian dinosaurs, particularly with regard to relative forelimb
length and thickness, and represents a transitional step toward the avian condition. In contrast with some recent comprehensive
phylogenetic analyses, our phylogenetic analysis incorporates subtle morphological variations and recovers a conventional
result supporting the monophyly of Avialae.
Supported by Hundred Talents Project of the Chinese Academy of Sciences, National Natural Science Foundation of China (Grant
Nos. 40125006, 40472018), and National Basic Research Program of China (Grant No. 2006CB806400) 相似文献
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Xu X Clark JM Forster CA Norell MA Erickson GM Eberth DA Jia C Zhao Q 《Nature》2006,439(7077):715-718
The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features. Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria. Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates. 相似文献