NONPARALLEL EFFECTS OF RENIN INHIBITOR TREATMENT ON PLASMA-RENIN ACTIVITY AND ANGIOTENSIN-I AND ANGIOTENSIN-II IN HYPERTENSIVE SUBJECTS - AN ASSAY-RELATED ARTIFACT

被引:39
作者
DERKX, FHM [1 ]
VANDENMEIRACKER, AH [1 ]
FISCHLI, W [1 ]
ADMIRAAL, PJJ [1 ]
VELD, AJMI [1 ]
VANBRUMMELEN, P [1 ]
SCHALEKAMP, MADH [1 ]
机构
[1] ERASMUS UNIV,DEPT INTERNAL MED 1,ROOM H 362,DR MOLEWATERPLEIN 40,3015 GD ROTTERDAM,NETHERLANDS
关键词
ANGIOTENSINS; ANTIHYPERTENSIVE DRUGS; PLASMA RENIN ACTIVITY; RENIN; RENIN INHIBITORS; PROTEIN BINDING;
D O I
10.1093/ajh/4.7.602
中图分类号
R6 [外科学];
学科分类号
1002 ; 100210 ;
摘要
Nonparallel effects of renin inhibitor treatment on plasma renin activity (PRA) and the plasma levels of angiotensins (ANG), as well as on blood pressure, have been observed in subjects with hypertension. This study addresses the possibility that renin inhibitors may show a high degree of plasma protein binding in vivo and that displacement of protein-bound inhibitor during the assay of PRA in vitro may lead to overestimation of renin inhibition. Indeed, with the ultrafiltration technique it was found that 96% of the novel renin inhibitor Ro 42-5892, when added to EDTA plasma, was bound to protein. The angiotensinase inhibitors phenylmethylsulfonyl fluoride (PMSF) and 8-hydroxyquinoline sulfate (8-OHQ), which are currently used in PRA assays, caused a displacement of protein-bound inhibitor, thereby increasing its free concentration. This displacement was sufficient to explain the reduction in IC 50 of Ro 42-5892, which was seen in the PRA assay when PMSF and 8-OHQ were added to plasma. Such reductions in IC 50 were also seen with the renin inhibitors CGP 29-287, CGP 38-560A, and SR 43-845. When Ro 42-5892 was given, 1 mg/kg intravenously in 10 min, to subjects with hypertension, it appeared that plasma ANG I and II returned to baseline after 6-8 h, whereas PRA measured in the presence of PMSF and 8-OHQ was still suppressed. However, when PRA was measured without these angiotensinase inhibitors, the inhibition of PRA was parallel to the suppression of ANG I and II. Thus, one must be cautious when using PRA to monitor the in vivo effects of renin inhibitors on the renin-angiotensin system, since the very method of PRA measurement may mislead the observer into overestimating the magnitude of drug effect.
引用
收藏
页码:602 / 609
页数:8
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