Wang Y Y, Wang Y L, Li H P, Zhu H S, Jiang Q D, Zhang L, Wang L F, Han L Q, Zhong K, Guo Y J, Lu W F, Li H J, Yang G Y
Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, Henan, PR China.
Genet Mol Res. 2011 Oct 21;10(4):3657-63. doi: 10.4238/2011.October.21.3.
Leptin is expressed in various tissues, suggesting that this protein is effective not only at the central nervous system level, but also peripherically. Recent studies have shown leptin production by other tissues, including the placenta, stomach, and mammary tissues, but there is no information available concerning expression levels of leptin in the rat mammary gland at different activation stages. We used semi-quantitative RT-PCR to investigate leptin mRNA expression levels in the rat mammary gland at different activity stages. Rat mammary gland samples were collected from virgin females and on days 6, 12, 18 of pregnancy and of lactation (six rats per group). The expression levels of leptin mRNA were measured by semi-quantitative RT-PCR, with β-actin as an internal control. Leptin mRNA was highly expressed in virgin rat mammary glands (leptin(IOD)/β-actin(IOD) = 1.60). It decreased gradually during pregnancy, being lowest at 18 days of pregnancy, when the levels were significantly lower than in virgin mammary tissue. Leptin mRNA increased slightly during lactation, but the difference was not significant. By day 18 of lactation, expression levels of leptin mRNA reached the same values as in virgin mammary tissue (leptin(IOD)/β-actin(IOD) = 1.65). Based on these results, we suggest that leptin has an important regulation role in rat mammary gland activation.
瘦素在多种组织中表达，这表明该蛋白不仅在中枢神经系统水平发挥作用，在外周组织也有作用。最近的研究表明包括胎盘、胃和乳腺组织在内的其他组织也能产生瘦素，但关于大鼠乳腺在不同激活阶段瘦素的表达水平尚无相关信息。我们使用半定量逆转录聚合酶链反应（RT-PCR）来研究大鼠乳腺在不同活动阶段瘦素mRNA的表达水平。从未孕雌性大鼠以及妊娠和哺乳的第6、12、18天采集大鼠乳腺样本（每组6只大鼠）。以β-肌动蛋白作为内对照，通过半定量RT-PCR测定瘦素mRNA的表达水平。瘦素mRNA在未孕大鼠乳腺中高表达（瘦素积分光密度值（IOD）/β-肌动蛋白积分光密度值（IOD） = 1.60）。在妊娠期间其表达逐渐降低，在妊娠第18天最低，此时的水平显著低于未孕乳腺组织。在哺乳期间瘦素mRNA略有增加，但差异不显著。到哺乳第18天，瘦素mRNA的表达水平达到与未孕乳腺组织相同的值（瘦素积分光密度值（IOD）/β-肌动蛋白积分光密度值（IOD） = 1.65）。基于这些结果，我们认为瘦素在大鼠乳腺激活中具有重要的调节作用。
