the effect of epinephrine on phosphatidate phosphohydrolase (pap) activity of isolated human hepatocytes was studied. epineprine inhibited the enzyme activity progressively at concentrations above 0.1 µm, reaching a maximum inhibition of 64.5% at 100 µm concentration. inclusion of alprenolol, a β-receptor blocker, in the incubation mixture abolished the inhibitory effect of epinephrine on pap, ...

Hormone sensitive lipase is thought to be the rate-limiting enzyme of lipolysis; phosphatidate phosphohydrolase that of lipogenesis. Both these enzyme systems were studied in vitro with the addition of epinephrine. The results show that: (a) hormone sensitive lipase is four times more active in rat epididymal fat than in sheep tail fat and (b) sheep omental fat is twice as active as tail fat. (...

To study the effects of alcoholic liver injury on the ability of ethanol to promote hepatic fat accumulation and hyperlipemia, baboons were pair-fed liquid diets containing 50% of energy either as ethanol or as additional carbohydrate (controls) for 1 to 7 years. Alcohol consumption produced triacylglycerol accumulation in the liver, hypertriacylglyceridemia, and various degrees of liver injury...

Assays for two distinct phosphatidate phosphohydrolase activities were established based upon a differential inhibition by N-ethylmaleimide (NEM). The activity that is insensitive to this reagent in rat liver is predominantly in the plasma membrane fraction, whereas the NEM-sensitive activity is in the cytosolic and microsomal fractions. The NEM-insensitive activity is further distinguished fro...

the effects of therapeutic doses of dillsun, garsin, antum and statins on rat liver cytosolic phosphatidate phosphohydrolase (pap) activity, a key enzyme in triacylglycerol synthesis, and on serum and liver lipids were examined. lovastatin and simvastatin both stimulated the enzyme activity by 29% and 43%, respectively. the stimulatory effects were dose-dependent and accompanied by the decline ...

phosphatidate phosphohydrolase (pap2b, fraction b) was purified from the plasma membrane ofrat liver cells. the km for the surface concentration of phosphatidic acid was 0.43 mol%. the subunit of theenzyme had an m.w. of 33.8 kda using sodium dodecyl sulfate polyacrylamide gel electrophoresis. thenative enzyme shows a molecular weight of 182 kda in a gel filtration column packed with sephacryl ...

1. Male rats were injected daily for 5 days with 0.15m-NaCl, corticotropin, cortisol or l-thyroxine and the rates of glycerolipid synthesis were measured in the livers after intraportal injection of [(14)C]palmitate and [(3)H]glycerol. 2. Injection of all three hormones decreased the rates of body-weight gain. 3. Cortisol treatment increased the weight of the liver relative to body weight. 4. T...

objective(s) phosphatidate phosphohydrolase (pap) catalyzes the dephosphorylation of phosphatidic acid to yield pi and  diacylglycerol. two different forms of pap in rat hepatocyte have been reported. pap1 is located in cytosolic and microsomal fractions and participates in the synthesis of triacylglycerols, phosphatidylcholine, and phosphatidylethanolamine, whereas the other form of phosphatid...

the effects of steroid hormones, glucagon and insulin on rat liver phosphatidate phosphohydrolase (pap) activity were studied both in vitro and in vivo. incubation of rat hepatocytes with each hormone showed that dehydroepiandrosterone (dhea), progesterone and testosterone increase pap activity by 44.6, 37 and 36.9%, respectively. estradiol, however, decreased enzyme activity by 13.6% under the...

Rat hepatocytes were incubated in monolayer culture in modified Leibovitz L-15 medium containing either 10% (v/v) newborn-calf serum or 0.2% (w/v) fatty-acid-poor bovine serum albumin. The addition of 100 nM-dexamethasone increased the activities of both phosphatidate phosphohydrolase and tyrosine aminotransferase by about 3.5-fold after 8h, and these activities continued to rise until at least...