Medullopressin: a new pressor activity from the renal medulla.
The kidney contains blood pressure-lowering substances, such as prostaglandin E2 or prostaglandin A2, and blood pressure-raising substances such as thromboxane A2. Most of the postulated substances, however, have not yet been isolated in a pure state and are of unknown structure. In the present study, we separated a chloroform extract from the medulla of pig kidneys using various chromatography procedures. Each fraction was tested in spontaneously hypertensive Wistar rats. One of these fractions caused a powerful blood pressure increase of 30.1 +/- 7.1 mmHg systolic and 34.7 +/- 6 mmHg diastolic (N=7; p=0.0003), reaching its maximum 55 +/- 27 s after completion of the injection and lasting for 201 +/- 59 s. A long-lasting contractile response in porcine and bovine coronary artery rings was observed. In the mouse aortic rings, the contractile response accounted for 0.38 +/- 0.13 g, ie., 31.9 +/- 10.9% of the maximum potassium response (N=11; p=0.003). Because this activity could not be attributed to any known vasoactive substance, it was considered to arise from a novel underlying active substance in the kidney medulla, which we named medullopressin.
Department of Radiology, Innsbruck Medical University, Austria. bernhard.glodny@uibk.ac.at
Bernhard
B
Glodny
Guido F
GF
Pauli
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002417:Cattle; D002845:Chromatography; D066298:In Vitro Techniques; D007679:Kidney Medulla / Q000737:chemistry*; D051379:Mice; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents