Nammi Srinivas, Dembele Korami, Nyomba B L Grégoire
John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, Manitoba, Canada R3E3P4.
Am J Physiol Regul Integr Comp Physiol. 2007 Mar;292(3):R1101-9. doi: 10.1152/ajpregu.00255.2006. Epub 2006 Nov 22.
Rat offspring prenatally exposed to alcohol display features of metabolic syndrome characterized by a low birth weight, catch-up growth, dyslipidemia, and insulin-resistant diabetes with increased gluconeogenesis, during adult life. Gluconeogenesis is partly regulated by cyclic AMP- and glucocorticoid-dependent mechanisms. Glucocorticoid action at the receptor level depends on its circulating concentrations and is amplified at the prereceptor level by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), which regenerates active glucocorticoids from inactive forms. To determine whether 11beta-HSD1 is dysregulated in this rat model, we examined the expression and enzyme activity of 11beta-HSD1 and its regulator enzyme hexose-6-phosphate dehydrogenase (H6PD) in the liver of postnatal day 7 (neonatal) and 3-mo-old (adult) rat offspring prenatally exposed to alcohol. Measurements of 11beta-HSD1 and H6PD were also performed in the omental fat of adult rat offspring. In both neonatal and adult rats, prenatal alcohol exposure resulted in increased tissue corticosterone concentrations, increased expression, and oxoreductase activity of 11beta-HSD1, and a parallel increase of H6PD expression. The data suggest that due to both transcriptional and posttranscriptional dysregulations, rats exposed to alcohol early in life have increased 11beta-HSD1 activity, which may explain insulin-resistant diabetes in these animals later in life.
产前暴露于酒精的大鼠后代在成年期表现出代谢综合征的特征,包括低出生体重、追赶生长、血脂异常以及伴有糖异生增加的胰岛素抵抗性糖尿病。糖异生部分受环磷酸腺苷和糖皮质激素依赖性机制调节。糖皮质激素在受体水平的作用取决于其循环浓度,并在受体前水平被11β-羟基类固醇脱氢酶1型(11β-HSD1)放大,该酶可将无活性形式的糖皮质激素再生为活性形式。为了确定11β-HSD1在该大鼠模型中是否失调,我们检测了产前暴露于酒精的出生后第7天(新生)和3个月大(成年)大鼠后代肝脏中11β-HSD1及其调节酶己糖-6-磷酸脱氢酶(H6PD)的表达和酶活性。还对成年大鼠后代的网膜脂肪进行了11β-HSD1和H6PD的测量。在新生和成年大鼠中,产前酒精暴露均导致组织皮质酮浓度升高、11β-HSD1的表达和氧化还原酶活性增加,以及H6PD表达平行增加。数据表明,由于转录和转录后失调,生命早期暴露于酒精的大鼠11β-HSD1活性增加,这可能解释了这些动物后期出现的胰岛素抵抗性糖尿病。