Ultramicro determination of serum triglycerides by bioluminescent assay.

The ultramicro (1-microL samples) assay of serum or plasma triglycerides that we describe here is potentially applicable to 1-nL samples and to isolated cells. This technically simple method involves only three reactions: (a) enzymic hydrolysis with lipase and alpha-chymotrypsin; (b) conversion by glycerol kinase of the liberated glycerol and of adenosine triphosphate added in excess to glycerol-1-phosphate and to adenosine diphosphate; and (c) assay of the residual adenosine triphosphate by the luciferin-luciferase reaction. The assay was optimized with respect to glycerol kinase, buffer, pH, temperature, and adenosine triphosphate. Performance characteristics compare well with those of traditional triglyceride assays.