[Effect of corticosterone on the contractile activity of the portal vein in the normotensive and hypertensive rat].

Corticosterone (28 nM/l) sharply increased the phasic tension of the portal vein whereas in dose 140 nM/l it sharply inhibited the phasic activity after its short enhancement, simultaneously, increasing the contraction rate and basal tone of the vessel in the normotensive Wistar-Kyoto rats. The initial response to corticosterone was absent in the spontaneously hypertensive rats, and their system maintaining the tonic component of contraction of the portal vein smooth muscles, was immediately activated. A primary membrane effect of the hormone on the vascular smooth muscle cells seems to be absent in the corticosterone effect on the spontaneous contractile activity of the portal vein in hypertensive animals.