CHANGES IN CYTOPLASMIC PH UPON HEAT-SHOCK IN EMBRYONIC AND ADULT-RAT LIVER-CELLS

All living cells, when exposed to elevated temperatures. undergo physi ological changes which result in the expression of a specific set of h eat shock proteins. Study of the possible physiological changes in adu lt and embryonic rat liver cells indicated a change in intracellular p H upon heat shock. Using 2', 7'-bis (2-carboxyethyl)-5 (and -6) carbox yfluorescein acetoxymethyl ester, we demonstrate here that the intrace llular pH of adult and embryonic liver cells is different and that the re is an increase in relative fluorescence intensity in both adult and embryonic cells upon heat shock, which corresponds to about 0-2 to 0. 3 pH units. We also show that in addition to heat. some of the inducer s of heat shock like response in many systems also induce a change in intracellular pH and induce heat shock proteins at 37-degrees-C in fet al liver cells. The possible mechanisms of induction of heat shock pro teins during heat shock and in the presence of inducers at normal temp erature are discussed.