Introduction

Some epidemiological studies have revealed that vitamin D (VD) deficiency is closely linked with the prevalence of obesity, however, the role of VD in energy homeostasis is yet to be investigated, especially in central nervous system. Given that VD negatively regulates renin in adipose tissue, we hypothesized that central VD might play a potential role in energy homeostasis.

Objectives

The present study aims to investigate the potential role of VD in energy homeostasis in the CNS and elaborate its underlying mechanisms.

Methods

This study was conducted in Cyp27b1^−/− mice, VD-treated and wild-type mice. After the intraventricular injection of renin or its inhibitors, the changes of renin-angiotensin system (RAS) and its down-stream pathway as well as their effects on metabolic rate were examined.

Results

The RAS activity was enhanced in Cyp27b1^−/− mice, exhibiting a increased metabolic rate. Additionally, corticotropin-releasing hormone (CRH), a RAS-mediated protein regulating energy metabolism in the hypothalamus, increased significantly in Cyp27b1^−/− mice. While in VD-treated group, the RAS and sympathetic nerve activities were slightly inhibited, hence the reduced metabolic rate.

Conclusion

Collectively, the present study demonstrates that the VD/vitamin D receptor (VDR) has a significant impact on energy homeostasis through the modulation of RAS activity in the hypothalamus, subsequently altering CRH expression and sympathetic nervous activity.

中文翻译：

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维生素 D/VDR 通过中枢肾素-血管紧张素系统调节外周能量稳态

介绍

一些流行病学研究表明，维生素 D (VD) 缺乏与肥胖的患病率密切相关，然而，VD 在能量稳态中的作用还有待研究，尤其是在中枢神经系统中。鉴于 VD 负调节脂肪组织中的肾素，我们假设中央 VD 可能在能量稳态中发挥潜在作用。

目标

本研究旨在探讨 VD 在 CNS 能量稳态中的潜在作用，并阐述其潜在机制。

方法

该研究在Cyp27b1 ^-/-小鼠、VD 治疗和野生型小鼠中进行。观察脑室内注射肾素或其抑制剂后肾素-血管紧张素系统(RAS)及其下游通路的变化及其对代谢率的影响。

结果

Cyp27b1 ^-/-小鼠的 RAS 活性增强，代谢率增加。此外，促肾上腺皮质激素释放激素 (CRH) 是一种 RAS 介导的调节下丘脑能量代谢的蛋白质，在Cyp27b1 ^-/-小鼠中显着增加。而在VD治疗组中，RAS和交感神经活动受到轻微抑制，因此代谢率降低。

结论

总的来说，本研究表明，VD/维生素 D 受体 (VDR) 通过调节下丘脑 RAS 活性对能量稳态产生重大影响，随后改变 CRH 表达和交感神经活性。