Title: Inhibition of Noradrenaline‐Stimulated Lipolysis and Cyclic AMP Accumulation in Isolated Rat Adipocytes by Purified Phospholipase C and Theta‐Toxin from <i>Clostridium Perfringens</i>
Abstract: Abstract Purified phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) and thetatoxin from Clostridium perfringens both inhibited noradrenaline‐stimulated lipolysis and cyclic AMP accumulation in isolated rat adipocytes in a dose‐dependent manner. The action of phospholipase C was gradual in onset, while the effect of theta‐toxin was almost immediate. Phospholipase C., but not theta‐toxin, hydrolyzed membrane phospholipids and inhibited adenylate cyclase (EC 4.6.1.1) in a crude membrane fraction from fat cells. The inhibitory effects of phospholipase C were associated with morphological alterations detectable by electron microscopy, whereas effects of theta‐toxin were observed at a time when no clearcut morphological alterations could be observed. It is concluded that the two purified principles from C. perfringens , which are both present in commercial preparations of phospholipase C., antagonize noradrenaline‐stimulated cyclic AMP accumulation and lipolysis. Although their exact mechanisms of action have not been elucidated, phospholipase C and theta‐toxin have different modes of attack.
Publication Year: 1978
Publication Date: 1978-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 10
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