The monoglyceride pathway for the synthesis of triglycerides has been investigated employing subcellular fractions and whole cell preparations of white and brown adipose tissue. Conclusive evidence has been obtained for the monoglyceride pathway in these tissues by employing the 2-monoether analogue of 2-monoolein as the substrate. The monoglyceride and α-glycerophosphate pathways were primarily found in the microsomal fraction. In these in vitro systems the activity of the monoglyceride pathway compared with the α-glycerophosphate pathway was of the same order of magnitude in whole cell preparations and was approximately one-half the activity of the α-glycerophosphate pathway when the microsomal fraction was employed.
