There is one clinical trial.
The current study is part of a large multi-investigator grant to look at the pharmacogenetics of a number of membrane transporters. We will study individuals with particular genotypes of the human organic cation transporter, (hOCT2), to test the hypothesis that genetic variation in hOCT2 is associated with variation in the renal clearance of the antidiabetic agent, metformin.
In recent studies, we identified four variants (M165I, A270S, R400C, and K432Q) with ethnic-specific allele frequencies ≥1%  that have altered function in studies in heterologous expression systems. --- M165I --- --- A270S --- --- R400C ---
We will also determine whether individuals who are heterozygous for the less common OCT2 variants, M165I, R400C and K432Q, have reduced renal clearances of metformin. --- M165I --- --- R400C ---
Description: To test whether individuals with genetic variants of the human organic cation transporter, OCT2, exhibit altered renal elimination of metformin we will measure the difference in renal clearance between reference and variant groups.Measure: Renal Clearance of Metformin Time: 0, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 hours