Induction of glomerulopressin production by cyclic AMP.
Isolated rat livers were perfused with gassed Krebs-Ringer-Bicarbonate and different doses of theophylline and dibutyryl cyclic AMP were added to the perfusing solution. The perfusates were ultrafiltrated through Diaflo UM-05 membranes. The glomerulopressin activity of the ultrafiltrates were assayed in the tonic tension contraction (TTC) of isolated stomach fundus from rats. As glomerulopressin is known to be a glucuronide, it was inactivated with beta-glucuronidase to confirm that the effect on the stomach fundus was due to the glomerulopressin and not to another substance. It was observed that doses of theophylline between 2 x 10(-3) M and 2 x 10(-5) M enhanced glomerulopressin production. However, there was no relationship between dose of theophylline and the response, and a dose of theophylline 2 x 10(-6) M has no activity. The perfusion with dibutyryl cyclic AMP at 5 x 10(-8) M increased the amount of glomerulopressin produced by the liver. This was a log-dose response of glomerulopressin production to dibutyryl cyclic AMP between 5 x 10(-8) M and 5 x 10(-4) M. Theophylline (2 x 10(-6) M) potentiated the activity of cyclic AMP (5 x 10(-8) M). These results support the view that cyclic AMP is intracellular mediator of the hepatic production of glomerulopressin.
Arany
E
E
Uranga
J
J
Bonetto
R
R
del Castillo
E
E
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D005934:Glucagon / Q000494:pharmacology; D005965:Glucuronates / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013806:Theophylline / Q000494:pharmacology
D005965:Glucuronates; C014007:glomerulopressin; D003994:Bucladesine; D005934:Glucagon; D013806:Theophylline; D000242:Cyclic AMP