[5] The role of the sodium-glucose cotransporter 1 is to absorb D-glucose and D-galactose from the brush-border membrane of the small intestines,[11][12] while also exchanging sodium ions and glucose from the tubule of the nephron.

[6] Co-transport proteins of mammalian cell membranes had eluded efforts of purification with classical biochemical methods until the late 1980s.

Size-fractionation of large amounts of rabbit intestinal mRNA with preparative gel electrophoresis were then sequentially injected into Xenopus oocytes to ultimately find the RNA species that induced the expression of sodium-glucose cotransport.

A missense mutation[4] in the SLC5A1 gene of exon 1 can cause problems creating the SGLT1 protein, leading to a very rare glucose-galactose malabsorption disease.

[4] Glucose-galactose malabsorption occurs when the lining of the intestinal cells cannot take in glucose and galactose which prevents the use of those molecules in catabolism and anabolism.

The disease has symptoms that consist of watery and/or acidic diarrhea which is the result of water retention in the intestinal lumen and osmotic loss created by non-absorbed glucose, galactose and sodium.