Background/Aims: Whey protein increases the secretion of GLP-1 from the gut. We tested whey protein and digests on GLP-1 secretion from human gut explants, known to contain GLP-1 secreting cells and on mouse derived STC-1 cells, frequently used to study GLP-1 secretion.
Methods: Human colon tissue wasfrom Biopta (Glasgow, UK). Samples were cultured with a negative control: Hank’s buffer, a positive control: meat peptone, undigested whey protein, partially digested whey protein (total protein, <1KDa and >1KDa fractions) fully digested whey protein (total protein, <1KDa and >1KDa fractions) and amino acids matched to whey protein, all at 25 mgs/ml. Samples were incubated for 2 hours and total GLP-1 measured using a total GLP-1 ELISA kit. Differences were tested using Student’s t-tests.
Results: Meat peptone stimulated the greatest secretion of GLP-1 from the explants compared to negative control (P<0.001), as expected, while undigested whey and the amino acid mixture resulted in no significant increase in GLP-1 secretion. Partial and full whey protein digests all significantly stimulated GLP-1 secretion to approximately the same extent compared to control (P<0.05). This was in contrast to experiments on STC-1 cells where the undigested whey protein resulted in a significant increase (P<0.05) in GLP-1 secretion compared to digests.
Conclusions: These results indicate that the use of STC-1 cells must be treated with caution when making assumptions regarding the efficacy of nutrients to elicit a GLP-1 response in humans.
Funding sources: Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS) and Innovate UK Grant 101.400