College of Health Solutions, Arizona State University, United States of America; School of Life Sciences, Arizona State University, United States of America.
School of Life Sciences, Arizona State University, United States of America.
Comp Biochem Physiol A Mol Integr Physiol. 2020 Jul;245:110703. doi: 10.1016/j.cbpa.2020.110703. Epub 2020 Apr 10.
Birds naturally maintain high glucose concentrations in the blood and tissues, even when relying on fat to meet the metabolic demands of flight or thermogenesis. One possibility is that high glucose levels might be needed to deal with these metabolic demands. Thus, we hypothesized that birds chronically exposed to colder temperatures and higher elevations have higher circulating glucose and tissue free glucose and glycogen compared to conspecifics living at warmer temperatures and lower elevations. Adult House Sparrows (Passer domesticus) and House Finches (Haemorhous mexicanus) were captured from Phoenix, AZ (340 m elevation), and Albuquerque, NM (1600 m elevation), during the summer and winter months. We measured plasma glucose, as well as free glucose and glycogen from multiple tissues. In general, high elevation and colder temperatures were associated with higher tissue glycogen and higher free glucose concentrations in the brain. These findings indicate that glucose and glycogen are subject to seasonal phenotypic flexibility as well as geographic variations that may relate to local food availability and abundance.
鸟类在血液和组织中自然维持着高浓度的葡萄糖，即使依靠脂肪来满足飞行或产热等代谢需求也是如此。一种可能性是，高葡萄糖水平可能是应对这些代谢需求所必需的。因此，我们假设与生活在温暖地区和低海拔地区的同种鸟类相比，长期暴露于较低温度和较高海拔地区的鸟类的循环葡萄糖和组织游离葡萄糖及糖原含量更高。我们在夏季和冬季从亚利桑那州凤凰城（海拔 340 米）和新墨西哥州阿尔伯克基（海拔 1600 米）捕获了家麻雀（Passer domesticus）和家朱雀（Haemorhous mexicanus）。我们测量了血浆葡萄糖以及来自多个组织的游离葡萄糖和糖原。总的来说，高海拔和较低温度与大脑中更高的组织糖原和更高的游离葡萄糖浓度有关。这些发现表明，葡萄糖和糖原受到季节性表型灵活性以及地理变化的影响，这些变化可能与当地食物的可获得性和丰度有关。
