Histochemical technique to detect choline-containing lipids

An almost specific and highly sensitive technique to detect histochemically choline-containing lipids is proposed. This technique is based on the effect of Hg++ and phosphomolybdic ion on the choline, that yields insoluble complexes able to react with diphenylcarbazide producing a deep blue or violet stain. The specificity and the sensitivity of this technique was investigated on filter paper strips loaded with choline-containing lipids, choline-free lipids, steroids, vitamins, proteins or choline hydrochloride. The results show that the choline-containing substances react positively. The choline-free substances react negatively except calciferol and vitamin A that show weakly positive results. This technique used on tissue sections appears very suitable to histochemical purposes.