title: Age-related changes in the translocation of phosphatidate phosphohydrolase from the cytosol to microsomal membranes in rat liver.
abstract: The effects of oleate, spermine and chlorpromazine were assayed in the presence or absence of 0.15 M KCl on the translocation of phosphatidate phosphohydrolase activity from cytosol to endoplasmic reticulum membranes in liver homogenates obtained from rats aged 1, 30, 60, 180 and 360 days. Marked age-associated decreases in phosphatidate phosphohydrolase distribution onto the membranes were demonstrated under nearly all conditions. In liver homogenates taken from 1-day-old rats and incubated with 0.15 M KCl, most of the enzyme was active (associated with the membranes). Physiological salt concentration (0.15 M KCl) produced a 2-fold increase of oleate-induced translocation of phosphatidate phosphohydrolase activity in liver homogenates from 1-day-old rats; it had no effect on those from 60-day-old rats, and produced a notable decline in liver homogenates obtained from 180- and 360-day-old rats. The promoting effect of spermine on oleate-induced translocation of this enzyme activity was higher in younger rats when incubated in the absence of 0.15 M KCl. Chlorpromazine did not show its usual antagonizing effect on oleate-induced translocation of phosphatidate phosphohydrolase when added to homogenates taken from 1-day-old rats. The antagonizing effect was slightly apparent in liver homogenates from 30-day-old rats and was more pronounced in those from 60-day-old rats in which the values diminished to one-half and to one-third either in the presence or absence of 0.15 M KCl.
authors.affiliation: Instituto de Bioquimica (CSIC-UCM), Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Cascales
authors.forename: L
authors.initials: L
authors.lastname: Boscá
authors.forename: A
authors.initials: A
authors.lastname: Martin
authors.forename: D N
authors.initials: DN
authors.lastname: Brindley
authors.forename: M
authors.initials: M
authors.lastname: Cascales
mesh_terms: D000375:Aging; D000818:Animals; D002746:Chlorpromazine / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D007425:Intracellular Membranes / Q000201:enzymology*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000254:growth & development*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D010711:Phosphatidate Phosphatase / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013096:Spermine / Q000494:pharmacology
chemical_list: D009829:Oleic Acids; D013096:Spermine; D019301:Oleic Acid; D011189:Potassium Chloride; D010744:Phosphoric Monoester Hydrolases; D010711:Phosphatidate Phosphatase; D002746:Chlorpromazine