Lactisole is an antagonist of sweet taste receptors, reducing both sweetness intensity and persistence. [1][2] It blocks the activation of the sweet taste receptor T1R3 by natural and synthetic sweeteners and increases the inhibition of T1R2 by umami compounds. [3][4] Lactisole can be used to explore the roles of these receptors in diverse pathways, including glucose-induced insulin secretion in pancreatic β-cells and the secretion of glucagon-like peptides by enteroendocrine L-cells. [3][5][6]

Reference:
[1]. Johnson, C., Birch, G.G., and MacDougall, D.B. The effect of the sweetness inhibitor 2(-4-methoxyphenoxy)propanoic acid (sodium salt) (Na-PMP) on the taste of bitter-sweet stimuli. Chem.Senses 19(4), 348-358 (1994).
[2]. Schiffman, S.S., Booth, B.J., Sattely-Miller, E.A., et al. Selective inhibition of sweetness by the sodium salt of ±2-(4-methoxyphenoxy)propanoic acid. Chem.Senses 24(4), 439-447 (1999).
[3]. Hamano, K., Nakagawa, Y., Ohtsu, Y., et al. Lactisole inhibits the glucose-sensing receptor T1R3 expressed in mouse pancreatic β-cells. Journal of Endocrinology 226(1), 57-66 (2015).
[4]. Shim, J., Son, H.J., Kim, Y., et al. Modulation of sweet taste by umami compounds via sweet taste receptor subunit hT1R2. PLoS One 10(4), (2015).
[5]. Ohtsu, Y., Nakagawa, Y., Nagasawa, M., et al. Diverse signaling systems activated by the sweet taste receptor in human GLP-1-secreting cells. Molecular and Cellular Endocrinology 394(1-2), 70-79 (2014).
[6]. Sato, S., Hokari, R., Kurihara, C., et al. Dietary lipids and sweeteners regulate glucagon-like peptide-2 secretion. Am. J. Physiol Gastrointest. Liver Physiol. 304(8), 304-308 (2013).