-transparent.png){kind=logo}
The regulation of neutral cytosolic cholesterol ester hydrolase was studied in isolated rat liver cells. Addition of glucagon to cell suspensions caused a decrease in the enzyme activity which was significant at 1 nM concentration. The cyclic nucleotide analogue bibutyryl cyclic AMP (10 and 100 microM) also inhibited the esterase activity. In the absence of calcium, glucagon did not produce any effect on the enzyme. To see if calcium was involved in a regulatory mechanism, cholesterol ester hydrolase activity was measured in cytosol from cells preincubated in a medium without calcium and containing EGTA. This treatment produced a marked reduction in cytosolic Ca2+ concentration with a concomitant threefold stimulation of the esterase activity. Readdition of calcium to Ca2(+)-deprived cells diminished the activation due to calcium deficiency. The present results suggest that 1) cholesterol ester hydrolase could be modulated by a cAMP-mediated mechanism elicited by glucagon in which Ca2+ appears to be involved and 2) the enzyme activity may also be regulated by changes in the intracellular calcium concentration.
M B Ruiz, and
B Ochoa, and
M Lacort
January 1986,
Drug metabolism and disposition: the biological fate of chemicals,
M B Ruiz, and
B Ochoa, and
M Lacort
September 1995,
Biochimica et biophysica acta,
M B Ruiz, and
B Ochoa, and
M Lacort
May 1974,
Endocrinology,
M B Ruiz, and
B Ochoa, and
M Lacort
January 1986,
FEBS letters,
M B Ruiz, and
B Ochoa, and
M Lacort
July 1983,
Lipids,
M B Ruiz, and
B Ochoa, and
M Lacort
February 1977,
Biochemical and biophysical research communications,
M B Ruiz, and
B Ochoa, and
M Lacort
August 1984,
Biochimica et biophysica acta,
M B Ruiz, and
B Ochoa, and
M Lacort
August 1983,
Biochimica et biophysica acta,
M B Ruiz, and
B Ochoa, and
M Lacort
June 1988,
Biochimica et biophysica acta,
M B Ruiz, and
B Ochoa, and
M Lacort
June 1986,
FEBS letters,
