Cardiac actions of bovine parathyroid hormone (1-34), isoproterenol, and propranolol in turtles.
1. In isolated turtle hearts bovine parathyroid hormone (b-PTH) (1-34) stimulated both force of contraction and rate (beats/min) apparently stimulating beats/min to a larger extent. 2. Isoproterenol stimulated both rate and force, perhaps affecting contractile force more. 3. Propranolol alone clearly decreased contractile force and beats/min. 4. Pre-treatment with propranolol removed stimulatory effects of both bPTH (1-34) and isoproterenol. Propranolol's effect on isoproterenol was expected. Its effect on bPTH (1-34) may be related to beta-stimulation by PTH or to some other non-specific inhibitory effect of propranolol.
Nichols
J R
JR
Department of Biology, Abilene Christian University, Texas 79699.
Eberts
E G
EG
D000818:Animals; D002417:Cattle; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D013045:Species Specificity; D013268:Stimulation, Chemical; D014426:Turtles
D010281:Parathyroid Hormone; D010446:Peptide Fragments; C025076:parathyroid hormone (1-34), bovine; D011433:Propranolol; D007545:Isoproterenol