Differential inhibition of plasma cholinesterase variants using the dibutyrate analogue of pancuronium bromide.

A steroid, the dibutyrate analogue of pancuronium bromide (9.8 X 10(-8)M), has been used as differential inhibitor in the study of the plasma cholinesterase variants. Pancuronium dibutyrate numbers have been measured for 190 individuals, and the mean values for six of the known genotypes, E1uE1u, E1uE1f, E1uE1a, E1fE1a, E1aE1a, and E1fE1f, have been calculated. Evidence is presented that a combination of the pancuronium dibutyrate number and the fluoride number give better resolution of the six genotypes than the combination of the pancuronium dibutyrate and the dibucaine number. This new differential inhibitor has real potential for revealing the probable existence of new genotypes.