The effect of cyclic AMP analogues and glucagon on cholesteryl ester synthesis and hydrolysis in cultured hamster hepatocytes

Hoang, Van-Quyen; Suckling, Keith E.; Cho-Chui, Y.S.; Botham, Kathleen M.

doi:10.1016/0014-5793(93)80183-u

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…study with cell-free systems, in which stimulation of neutral microsomal CEH was seen after treatment of rat liver microsomes with a cAMP-dependent protein kinase or with Ca2+/calmodulin (26), and with a recent report by Hoang et al (21), indicating stimulation of neutral CEH activity by cAMP analogues and glucagon in the post-mitochondrial supernatant of cultured hamster hepatocytes.…”

Section: The Data Presented Herein Provide Evidence That Exposure Of mentioning

confidence: 60%

“…The inhibition of ~-hydroxy-~-methylglutaryl-CoA reductase activity in its phosphorylated form is well established (15)(16)(17). Contradictory results have appeared about the regulation of acyl-CoA:cholesterol acyltransferase (18)(19)(20)(21) and bile acid synthesis (22)(23)(24) by second messenger-mediated processes. Much evidence has accumulated supporting the concept that cytosolic CEH is activated by cAMP-dependent phosphorylation in steroidogenic and other nonhepatic tissues.…”

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confidence: 99%

“…In addition, the inhibitory effect of okadaic acid was found not to be related to the dibutyryl cAMP (db-cAMP)-promoted stimulation of esterase activity (27). Hoang et al (21) reported stimulation of neutral CEH activity by cAMP analogues and glucagon in the post-mitochondrial supernatant of cultured hamster hepatocytes, but there are no systematic studies on the effects of these compounds on the neutral microsomal cholesterol ester hydrolysis in isolated rat hepatocytes.…”

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confidence: 99%

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Stimulation of microsomal cholesterol ester hydrolase by glucagon, cyclic AMP analogues, and vasopressin in isolated rat hepatocytes

Hernández

Martı́nez

Ruíz

et al. 1996

Lipids

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Short-term activation of microsomal cholesterol ester hydrolase by glucagon, cAMP analogues, and vasopressin in isolated rat hepatocytes is described. Glucagon led to a dose- and time-dependent activation of cholesteryl oleate hydrolysis, but values returned to basal levels within 120 min. Exposure of isolated hepatocytes to 0.5 mM concentrations of dibutyryl-cAMP or 8-[4-chlorophenylthio]-cAMP, or 25 microM forskolin caused persistent activation of cholesterol ester hydrolase activity after a lag period of 30 min. The three agents resulted in early marked intracellular accumulation of cAMP that declined progressively, and moderate and sustained reductions in the diacylglycerol content. The actions of glucagon on hepatocytes were inhibited by pretreatment of cells with 10 nM [8-arginine] vasopressin. Vasopressin elicited a consistent and sustained increase in cholesterol ester hydrolase activity and diacylglycerol without affecting cAMP while reducing the effect of glucagon on cAMP. Furthermore, the effects of glucagon and vasopressin on the activation of cholesterol ester hydrolase were not additive despite the similarity of their stimulation of diacylglycerol formation. Blockade of vasopressin-mediated activation of cholesterol ester hydrolase and diacylglycerol content were induced by excess prazosin. These data suggest that stimulation of microsomal cholesterol ester hydrolase in isolated liver cells may involve at least two signal transduction systems.

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Section: The Data Presented Herein Provide Evidence That Exposure Of mentioning

confidence: 60%