Ca2+/calmodulin-dependent protein kinase kinase-alpha regulates skeletal muscle glucose uptake independent of AMP-activated protein kinase and Akt activation

Studies in nonmuscle cells have demonstrated that Ca(2+)/calmodulin-dependent protein kinase kinases (CaMKKs) are upstream regulators of AMP-activated protein kinase (AMPK) and Akt. In skeletal muscle, activation of AMPK and Akt has been implicated in the regulation of glucose uptake. The objective of this study was to determine whether CaMKKalpha regulates skeletal muscle glucose uptake, and whether it is dependent on AMPK and/or Akt activation. Expression vectors containing constitutively active CaMKKalpha (caCaMKKalpha) or empty vector were transfected into mouse muscles by in vivo electroporation. After 2 weeks, caCaMKKalpha was robustly expressed and increased CaMKI (Thr(177/180)) phosphorylation, a known CaMKK substrate. In muscles from wild-type mice, caCaMKKalpha increased in vivo [(3)H]-2-deoxyglucose uptake 2.5-fold and AMPKalpha1 and -alpha2 activities 2.5-fold. However, in muscles from AMPKalpha2 inactive mice (AMPKalpha2i), caCaMKKalpha did not increase AMPKalpha1 or -alpha2 activities, but it did increase glucose uptake 2.5-fold, demonstrating that caCaMKKalpha stimulates glucose uptake independent of AMPK. Akt (Thr(308)) phosphorylation was not altered by CaMKKalpha, and caCaMKKalpha plus insulin stimulation did not increase the insulin-induced phosphorylation of Akt (Thr(308)). These results suggest that caCaMKKalpha stimulates glucose uptake via insulin-independent signaling mechanisms. To assess the role of CaMKK in contraction-stimulated glucose uptake, isolated muscles were treated with or without the CaMKK inhibitor STO-609 and then electrically stimulated to contract. Contraction increased glucose uptake 3.5-fold in muscles from both wild-type and AMPKalpha2i mice, but STO-609 significantly decreased glucose uptake (approximately 24%) only in AMPKalpha2i mice. Collectively, these results implicate CaMKKalpha in the regulation of skeletal muscle glucose uptake independent of AMPK and Akt activation.     

维生素C及E联合作用对体外大鼠胚胎中脑神经细胞分化和增殖的影响

目的:观察维生素C,维生素E和维生素C 维生素E联合后对胚胎中脑神经细胞生长发育的影响。方法:实验于2006-03/04在江苏大学医学院研究中心细胞培养室完成。采用16d大鼠胚胎中脑神经细胞体外培养方法,观察不同剂量的维生素C(5,10,25,50μmol/L),维生素E(10,25,50,100μmol/L)和维生素C、维生素E联合作用(维生素C25μmol/L 维生素E50μmol/L,维生素C50μmol/L 维生素E100μmol/L),培养10d后收集细胞,并利用图像分析细胞形态的变化、蛋白质、丙二醛含量及超氧化物歧化酶活性指标。结果:①维生素C、维生素E和维生素C 维生素E联合能促进体外培养中脑神经细胞突起生长,集落数增多。②与正常对照组比较,维生素C10,25μmol/L组、维生素E10,25,50μmol/L组、维生素C25μmol/L 维生素E50μmol/L组神经细胞总蛋白相对含量明显增加。③与正常对照组比较,维生素C10,25μmol/L组、维生素E25,50μmol/L组、维生素C25μmol/L 维生素E50μmol/L组神经细胞超氧化物酶活性增加,丙二醛含量降低。④维生素C50μmol/L组、维生素E100μmol/L组和维生素C50μmol/L 维生素E100μmol/L组超氧化物酶活性低于正常对照组,丙二醛含量高于正常对照组。结论:维生素C、维生素E和维生素C 维生素E联合剂量在一定范围内能够明显提高中脑神经细胞的抗氧化能力,同时能促进胚胎中脑神经细胞分化和增殖作用。     

海风藤中新木脂素类PAF拮抗活性成分的研究

自中药海风藤[Piper kadsura (Choisy)Ohwi]的藤茎中又分离得到四个macrophyllin型双环[3,2,1]辛烷类新木脂素,经光谱分析及衍生物的制备,确定化合物Ⅰ和Ⅲ为新结构,命名为风藤素K(kadsurenin K)和风藤素L(kadsurenin L),其化学结构分别为7R,8R,3′R,5′R-△^8′-3,5′-二甲氧基-4-羟基-2′,3′,4′,5′-四氢-2′,4′-氧-7.3′,8.5′-新木脂素(Ⅰ)和7R,8R,3′S,4′R,5′R-△^8′-3,4,5′-三甲氧基-4′-乙酰氧基-2′,3′,4′,5′-四氢-2′-氧-7.3′,8.5′-新木脂素(Ⅲ)。化合物Ⅱ和Ⅳ分别为已报道过的风藤素C和风藤素B。化合物Ⅰ～Ⅳ均有明显的PAF受体拮抗活性。     

苦瓜子有效成分研究

从苦瓜(Momordica charantia L.)的种子中,分离出五种成分,经光谱和化学方法确定其结构为:蚕豆甙,海藻糖,24β-乙基-5α-胆甾-7,反式-22E,25(27)-三烯,-3β-羟、基-3-O-β-D-吡喃葡萄糖甙,苦瓜子甙A,苦瓜子甙B。海藻糖系首次从该植物中分出,甾醇甙系首次从苦瓜属植物中分出,两个苦瓜子甙系新化合物。苦瓜子甙A对S180动物瘤组织DNA和RNA蛋白质合成有显著抑制作用。     

Sexual Dimorphism in Titi Monkeys’ Digit (2D:4D) Ratio is Associated with Maternal Urinary Sex Hormones During Pregnancy

The second-to-fourth digit (2D:4D) ratio is a sexually-dimorphic biomarker for prenatal sex hormone exposure. We investigated whether titi monkeys (Plecturocebus cupreus) exhibit sexually-dimorphic 2D:4D ratio, and whether variation in 2D:4D ratio correlates with maternal testosterone and estrogen levels during early pregnancy. Subjects were 61 adult titi monkeys (32 males, 29 females). For 26 subjects, maternal urine samples were collected approximately 15–20 weeks before birth and assayed for testosterone and estrone conjugate (E₁C). Titi monkeys exhibited a human-like pattern of sexual dimorphism in right-hand 2D:4D ratio, with females exhibiting higher 2D:4D ratio than males (β = −0.29, p = 0.023). For left-hand 2D:4D ratio, high levels of maternal E₁C predicted low offspring 2D:4D ratio (β = −0.48, p = 0.009). For right-hand 2D:4D ratio, high levels of testosterone (β = −0.53, p = 0.005) and testosterone-to-E₁C ratio (β = −0.41, p = 0.028) predicted low offspring 2D:4D ratio. For 2D:4D ratio asymmetry (right-hand – left-hand), high levels of testosterone (β = −0.43, p = 0.03) and testosterone-to-E₁C ratio (β = −0.53, p = 0.003) predicted low (right-biased) asymmetry. This is the first report of sexually-dimorphic 2D:4D ratio in New World monkeys, and the results support a growing literature suggesting prenatal sex hormones may modulate offspring 2D:4D ratio.