Win 58237 is an inhibitor of cyclic nucleotide phosphodiesterase (PDE) (Ki: 170 nM for PDE V), with vasorelaxant activity.

PDE5:ki:170 nM

Win 58237 is a competitive cGMP PDE V inhibitor from canine aorta(Ki : 170 nM). Win 58237 is a potent PDE V inhibitor isolated from vascular tissue (IC50 : 240 nM). It is a relatively less potent calmodulin-sensitive PDE I and cGMP-inhibitable cyclic AMP PDE III inhibitor ; but does inhibit cyclic AMP PDE IV with an IC50 value of approximately 300 nM. Win 58237 possesses vasorelaxant activity in the presence of an intact endothelium or nitric oxide.

In vivo, Win 58237 (0.3-3.0 mg/kg i.v.) decreases mean arterial pressure in conscious spontaneously hypertensive rats with an associated increase in vascular (aortic) cGMP content . Win 58237 (10 mg/kg i.v.) increases plasma cGMP levels, from basal levels of 6.7 ± 1.0 to 31.4 ± 3.5 fmol/μL.