Glp1r, the glucagon-like peptide-1 receptor, is a key component in glucose-related physiological processes. It is activated by glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L cells after nutrient consumption. GLP-1R activation potentiates glucose-induced insulin secretion from pancreatic beta cells, inhibits beta-cell apoptosis, reduces glucagon secretion, delays gastric emptying, promotes satiety, and increases peripheral glucose disposal [2]. These functions link nutrient consumption with blood sugar control, making Glp1r crucial in maintaining metabolic homeostasis.

Polymorphisms in Glp1r are associated with type 2 diabetes. For instance, the G-risk allele at rs761387 was associated with higher total GLP-1, active GLP-1, and a trend toward higher glucose during an oral glucose tolerance test (OGTT), while during a glipizide challenge, it was associated with higher insulin levels. However, other tested variants (rs10305423, rs10305441, rs742762, and rs10305492) were not associated with the tested outcomes. This shows that Glp1r variation can affect GLP-1 levels and potentially the risk of type 2 diabetes through altered incretin signaling [1]. Also, in overweight Chinese type 2 diabetes patients, the variant allele T of rs10305420 was associated with less weight loss and lower HbA1c reduction after 6 months of exenatide (a Glp1r agonist) treatment, indicating its potential as a biomarker for precision medicine in this patient group [3].

In conclusion, Glp1r is essential for regulating glucose metabolism and energy balance. Genetic variations in Glp1r can influence the risk of type 2 diabetes and the response to Glp1r-targeted therapies. Understanding Glp1r through genetic studies, like those examining polymorphisms, provides insights into the molecular mechanisms underlying metabolic diseases and may guide the development of more personalized treatment strategies for type 2 diabetes.

References:

1. Dorsey-Trevino, Edgar G, Kaur, Varinderpal, Mercader, Josep M, Florez, Jose C, Leong, Aaron. . Association of GLP1R Polymorphisms With the Incretin Response. In The Journal of clinical endocrinology and metabolism, 107, 2580-2588. doi:10.1210/clinem/dgac374. https://pubmed.ncbi.nlm.nih.gov/35723666/

2. Donnelly, Dan. . The structure and function of the glucagon-like peptide-1 receptor and its ligands. In British journal of pharmacology, 166, 27-41. doi:10.1111/j.1476-5381.2011.01687.x. https://pubmed.ncbi.nlm.nih.gov/21950636/

3. Yu, Mingjun, Wang, Kaiyu, Liu, Haiming, Cao, Rui. 2019. GLP1R variant is associated with response to exenatide in overweight Chinese Type 2 diabetes patients. In Pharmacogenomics, 20, 273-277. doi:10.2217/pgs-2018-0159. https://pubmed.ncbi.nlm.nih.gov/30883264/