摘要：A phosphorus-free lipid with a transient antihypertensive effect was found in a dog peritoneal dialysate by a modified procedure. On silicic acid chromatography of the crude extract, a new hypotensive factor and a new hypertensive factor were separated besides the known antihypertensive phospholipid resembling lysolecithin (Peritoneal dialysate depressor-I). The new antihypertensive factor was purified almost completely by gel filtration on a Sephadex LH-20 column, and found to contain no phosphorus. It was tentatively named Peritoneal Dialysate Depressor-II. The main spot detected on preparative thin-layer chromatography by charring with ethanolic sulturic acid reagent was found to be responsible for the antihypertensive action. This factor caused a sharp decrease in systemic arterial blood pressure of rats, cats and guired pigs when injected into the femoral vein. There was no significant change in the heart rate during this hypotension. The hypotensive activity was not affected by previous treatment of the rats or guinea pigs with antimuscarinic, antihistaminic, β-adrenergic-blocking or ganglionic-blocking agents. The antihypertensive effect of the factor was unaffected on rats pretreated with yohimbine, indomethac in or theophylline. In spinal or reserpinized rats, no detectable reduction of the depressor activity was observed. The factor did not affect isolated guinea pig ileum. Its depressor activity was not changed significantly by its treatment with proteases. No prostaglandin E or F series compounds were detected in the preparation by fluorometric assay with 15-hydroxyprostanoate oxido-reductase and resazurin. The hypotensive factot caused no aggregation of cat or rabbit platelets. The activity was not due to any known antihypertensive agent, such as acetylcholine, histamine, substance P, bradykinin, prostaglandins, platelet activating factor, lysophosphatidic acid and other known depressor compounds, as shownby various chemical and pharmacological examinations. Thus, the new hypotensive factor seems to be a lable lipid containing no phosphorus.
