Volume 13, Number 2 (8-1999)                   Med J Islam Repub Iran 1999 | Back to browse issues page


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HAGHIGHI B, TOORI S, SHAJARIAN S. EPINEPHRINE INHIBITS THE A CTIVITY OF PHOSPH ATIDATE PHOSPHOHYDROLASE OF ISOLATED HUMA N HEPATOCYTES. Med J Islam Repub Iran. 1999; 13 (2) :139-142
URL: http://mjiri.iums.ac.ir/article-1-958-en.html

From the Department of Clinical Biochemistry, Isfahan University of Medical Sciences, Isfahan, I.R.Iran
Abstract:   (1804 Views)
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, whereas the (i-receptor antagonist phentolamine, or agonist phenylephrine, did not significantly change the hormone's effect. Addition of dibutyryl-cAMP or .aminophylline (a cAMP phosphodiesterase inhibitor) to the incubation mixture together with epinephrine caused further enzyme inhibiti.on reaching 65.6% and 63.7%, respectively, compared to 49% inhibition caused by epinephrine alone under the same conditions. Dibutyryl-cAMP alone also inhibited PAP activity (51 %). The results suggested that epinephrine affects human hepatocyte PAP activity through β-adrenoceptor activation and cAMP is involved in the mechanism by which PAP activity is altered.
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