Desmosterol: a biomarker for the efficient development of 20,25-diazacholesterol as a contraceptive for pest wildlife.

Abstract

20,25-Diazacholesterol is being evaluated as a contraceptive for the nonlethal control of avian and mammalian wildlife pests. The identification of an analyte in blood which was highly correlated with absorbed dose and efficacy is valuable for determining effective formulations and dosing variables. Such an analyte or biomarker is also valuable for determining the percentage of pest populations that consume an effective dose of the active ingredient in the field. HPLC analyses of blood collected from dosed animals failed to detect 20,25-diazacholesterol but indicated that levels of free cholesterol and related compounds were affected by 20,25-diazacholesterol absorption. The greatest percent change in chromatographic peak area associated with 20,25-diazacholesterol administration was observed for desmosterol, a cholesterol precursor. 20,25-Diazacholesterol appeared to block the conversion of desmosterol to cholesterol, resulting in an elevated concentration of the precursor. The elevation of blood desmosterol levels is being used as an indicator of 20,25-diazacholesterol absorption and to facilitate the development of a 20,25-diazacholesterol-based contraceptive for pest wildlife.