Roles of Ghrelin and Leptin in Body Mass Regulation under Food Restriction Based on the AMPK Pathway in the Red-Backed Vole, Eothenomys miletus, from Kunming and Dali Regions

Abstract

The phenotype plasticity of animals’ physiological characteristics is an important survival strategy to cope with environmental changes, especially the change in climate factors. Small mammals that inhabit seasonally changing environments often face the stress of food shortage in winter. This study measured and compared the thermogenic characteristics and related physiological indicators in the adenosine-5′-monophosphate-activated protein kinase (AMPK) pathway in Eothenomys miletus between Kunming (KM, n = 18) and Dali (DL, n = 18) under food restriction and refeeding. The results showed that food restriction and the region have significant effects on body mass, the resting metabolic rate (RMR), hypothalamic neuropeptide gene expression, ghrelin levels in the stomach and serum, serum leptin level and the activity of AMPK, and malonyl CoA and carnitine palmitoyltransferase 1 (CPT-1) activity. Food restriction reduced the body mass, the gene expression of neuropeptide proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcription peptide (CART), and leptin level. However, the ghrelin concentration and AMPK activity increased. After refeeding, there was no difference in these physiological indexes between the food restriction and control groups. Moreover, the physiological indicators also showed regional differences, such as the body mass, POMC and CART gene expression, ghrelin concentration in the stomach and serum, and AMPK activity in DL changed more significantly. All these results showed that food restriction reduces energy metabolism in E. miletus. After refeeding, most of the relevant physiological indicators can return to the control level, indicating that E. miletus has strong phenotypic plasticity. Ghrelin, leptin, and the AMPK pathway play an important role in the energy metabolism of E. miletus under food restriction. Moreover, regional differences in physiological indicators under food restriction may be related to the different temperatures or food resources in different regions.

Two Hormones: Ghrelin and Leptin, Based on AMPK Signaling Pathway, Play a Role in Body Mass Control of Eothenomys miletus during Fasting in Kunming and Dali Regions

“…A difference of significance of P<0.05 is shown and the results are presented as means± SE. Measurements was details in Liu et al (2022).…”

“…E. miletus were transported back to the Yunnan Normal University lab where they were kept alone in a clear plastic box (260 mm  160 mm  150 mm) at a temperature of 25±1C with an 8L:16D photoperiod. Detailed processing methods was in Liu et al (2022). All animal procedures were within the rules of Animals Care and Use Committee of School of Life Sciences, Yunnan Normal University.…”

“…Measurements was details in Liu et al (2022). AMPK activity, malonyl-COA activity, CPT-1 activity, serum leptin and total ghrelin content and stomach ghrelin content were measured by enzyme-linked immunosorbent assay (ELISA) kits.…”