Spexin 1 is an endogenous peptide and agonist of galanin-2 receptor (GAL2) and GAL3.1 It selectively activates GAL2 and GAL3 over GAL1 in HEK293 cells expressing the human receptors and Gαqi (EC50s = 0.161, 0.626, and >10 µM, respectively, in reporter assays). Spexin 1 (50 µg/kg) decreases body weight, fat mass, serum triglyceride levels, and blood glucose and insulin levels in a mouse model of high-fat diet-induced hepatic steatosis.2 Intracerebroventricular administration of spexin 1 (30 nmol/animal) decreases heart rate and urine flow rate, increases mean arterial pressure (MAP) and urinary sodium excretion, and has antinociceptive activity in the warm water tail withdrawal test in rats.3
1.Kim, D.-K., Yun, S., Son, G.H., et al.Coevolution of the spexin/galanin/kisspeptin family: Spexin activates galanin receptor type II and IIIEndocrinology155(5)1864-1873(2014) 2.Wang, M., Zhu, Z., Kan, Y., et al.Treatment with spexin mitigates diet-induced hepatic steatosis in vivo and in vitro through activation of galanin receptor 2Mol. Cell Endocrinol.552111688(2022) 3.Toll, L., Khroyan, T.V., Sonmez, K., et al.Peptides derived from the prohormone proNPQ/spexin are potent central modulators of cardiovascular and renal function and nociceptionFASEB J.26(2)947-954(2011)