title: Action of phenylisopropyl-adenosine (PIA) on the synthesis of corticosterone in rats.
abstract: The effects of the stereoisomers of phenylisopropyl-adenosine (l- and d-PIA) were studied on the synthesis of corticosterone in rats in vivo and in rat adrenal slices in vitro. In vivo l- and d-PIA elevated plasma corticosterone level in normal but not in dexamethasone-pretreated rats. l-PIA was at least 20 times more active than d-PIA. The ACTH-stimulated steroidogenesis was modified by pretreatment with l-PIA neither in normal nor in dexamethasone-treated rats. Adrenal slices prepared from the l-PIA-pretreated rats were less sensitive in vitro to the stimulatory action of ACTH or N6,2'-O-dibutyryl-3',5'-adenosine monophosphate (DBA) than those from control animals. In vitro l- and d-PIA slightly increased the basal steroidogenesis. On the other hand, both the ACTH- and DBA-stimulated synthesis of corticosterone was inhibited by l- and d-PIA to approximately the same degree. The type of inhibition proved to be competitive in ACTH-stimulated and non-competitive in DBA-stimulated steroidogenesis. l- and d-PIA did not disturb the release process of corticosterone from the adrenal tissue into the incubation medium.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives*; D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000096:biosynthesis* / Q000097:blood; D066298:In Vitro Techniques; D008297:Male; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D051381:Rats; D013806:Theophylline / Q000494:pharmacology
chemical_list: D010660:Phenylisopropyladenosine; D013806:Theophylline; D000241:Adenosine; D003345:Corticosterone