Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia.
Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia.
Nutrients. 2020 Aug 19;12(9):2493. doi: 10.3390/nu12092493.
The stomach is the primary source of the orexigenic and adiposity-promoting hormone, ghrelin. There is emerging evidence on the nutrient-mediated modulation of gastric ghrelin secretion. However, limited information is available on gastric nutrient-sensing mechanisms in high-fat diet (HFD)-induced obesity. This study investigated the impact of HFD-induced obesity on the expression of nutrient chemosensors in mouse stomach, particularly ghrelin cells. Male C57BL/6 mice were fed either a standard laboratory diet (SLD) or HFD for 12 weeks. The expression of ghrelin, enzymes involved in ghrelin production (PC1/3, GOAT) and nutrient chemosensors (CD36, FFAR2&4, GPR93, CaSR, mGluR4 and T1R3) was determined by quantitative RT-PCR in the mouse corpus and antrum. Immunohistochemistry assessed the protein expression of CaSR and ghrelin in the corpus and antrum. Antral mRNA levels of CaSR and PC1/3 were increased in HFD compared to SLD mice, while mRNA levels of all other nutrient chemosensors examined remained unchanged. CaSR immunolabelling was observed in the gastric antrum only. Nearly 80% of antral ghrelin cells expressed CaSR, with a similar cell density and co-expression in SLD and HFD mice. In conclusion, HFD-induced obesity increased CaSR mRNA expression in mouse antrum. However, the high antral co-expression of CaSR and ghrelin was unaltered in HFD compared to SLD mice.
胃是产生食欲刺激和促进肥胖的激素——ghrelin 的主要来源。有越来越多的证据表明，营养素可以调节胃 ghrelin 的分泌。然而，关于高脂肪饮食（HFD）诱导肥胖对胃营养感受器的影响的信息有限。本研究调查了 HFD 诱导肥胖对小鼠胃中营养感受器表达的影响，特别是 ghrelin 细胞。雄性 C57BL/6 小鼠分别用标准实验室饮食（SLD）或 HFD 喂养 12 周。通过定量 RT-PCR 检测小鼠胃体和胃窦中 ghrelin、ghrelin 产生相关酶（PC1/3、GOAT）和营养感受器（CD36、FFAR2&4、GPR93、CaSR、mGluR4 和 T1R3）的表达。免疫组织化学检测胃体和胃窦中 CaSR 和 ghrelin 的蛋白表达。与 SLD 相比，HFD 组小鼠胃窦 CaSR 和 PC1/3 的 mRNA 水平增加，而其他营养感受器的 mRNA 水平保持不变。仅在胃窦中观察到 CaSR 的免疫标记。近 80%的胃窦 ghrelin 细胞表达 CaSR，SLD 和 HFD 小鼠的细胞密度和共表达相似。总之，HFD 诱导的肥胖增加了小鼠胃窦 CaSR 的 mRNA 表达。然而，与 SLD 相比，HFD 对胃窦 ghrelin 细胞中 CaSR 和 ghrelin 的高共表达没有影响。
