抄録
Post-mortem breakdown of P32-labelled phosphoinositides and phosphatidic acid in guinea-pig brain was studied utililyzing liquid oxygen for fixation. The incorpora-tion of P32-phosphate into phosphoinositides and phosphatidic acid in brain tissue in various states of the tissue was also studied. The results are summarized as follows; 1) Depletion of P32-labelled triphosphoinositide on thawing brain was extremely rapid, amounting to 63 per cent after 10 mintes and 91 per cent after 30 minutes at 30°C. The depletions of P32-labelled di-, monophospho-inositide and phosphatidic acid were 52, 14 and 39 per cent respectively, after 10 minutes under the same conditions. 2) The incorpora-tion of P32-phosphate into polyphosphoinosi-tides in brain slices was much more stimulated by the addition of sodium ion, than that into phosphatidic acid. The degree of stimulation of incorporation into monophosphoinositide was smaller than that into polyphosphoinositide. 3) P32-incorpora-tion into phosphoinositides and phosphatidic acid in brain tissue was changed conside-rably by changes in the state of the tissue i.e, in tissue in vivo, in slices or homogenates, and by changes in the incubation medium. 4) Polyphosphoinositides in concentrated HC1-chloroform-methanol (1:200:100) were quite stable for at least 18 hours at 4°C.
