572
Agents and Actions vol. 8/6 (1978) Birkh/iuser Verlag, Basel
Urinary Kallikrein Excretion and Plasma DBH Activity in Hypertension b y A.V. GRECO, G. PORCELLI, J.F. MAGALHAES 1) ~ind L. ALTOMONTE Istituto di Patologia Medica and Istituto di Chimica, Catholic University, Rome, Italy, and Centro Chimica dei Recettori C.N.R., Rome, Italy
Abstract Many factors are to be considered in maintaining normal blood pressure. Authors study the behavior of urinary kailikrein (U;K.) and plasma dopamine-[3hydroxylasc (DBH) activity in varioias forms of hypertension. The values of U.K. excretion in normals were 20.5 + 1.8 E.U./24 h. In essentlal hypertensive patients (9.4 + 2.0 E.U./24 h) U.K. decreased, while in secondary hypertension it was significantly higher (33.8 _+ 3.0 E.U./24 h). Plasma DBH activity in essential hypertensive patients (17.72 + 2.33 I.U./ml) was similar to controls (20.22 _+ 1.39 I.U./ml); in secondary hypertension the mean values of plasma DBH were decreased (12.31 + 2.55 I.U./ml). No correlation between U.K. and plasma DBH activity was observed in normals and in various forms of hypertensive patients. U.K. seems a more reliable factor than plasma DBH in defining the different types of hypertension.
The pathogenesis of h y p e r t e n s i o n is subject to discussion. A p a r t from m a n y extra-renal factors (central n e r v o u s system, a u t o n o m i c nervous system, adrenal h o r m o n e s ) , there is a complicated renal blood pressure regulation syst e m to which belong molecules with a vasoconstrictor action (mostly renin) and, m u c h less studied, molecules with a v a s o d i l a t a t o r action (prostaglandins, kallikrein-kinin system). ELLIOT a n d N u z u M [11], MARGOLZUS et al. [2] a n d GRECO et al. [3] showed that a decrease of u r i n a r y kallikrein (U.K.) o c c u r s in patients with essential hypertension: I n various f o r m s of h y p e r t e n s i o n the blood level of dopamine-fl-hydroxylase ( D B H ) , the enZyme that c o n v e r t s d o p a m i n e to norepinephrine, has b e e n suggested as a satisfactory indicator for diagnosis [4, 5, 6]. 1)Present address:!?Facultade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Brazil.
O u r study was u n d e r t a k e n to define the range of U . K . a n d of p l a s m a D B H activity in diverse types of h y p e r t e n s i o n a n d to d o c u m e n t relative differences between these forms. Methods
58 normal male patients, 19-40 years old, 20 patients with secondary hypertension, 18-60 years old, and 23 essential hypertensive patients, 17-56 years of age, were studied. Before the study, the subjects had not received any drug for at least two weeks and were submitted to a Na+-free diet. Tests of blood creatinine, endogenous clearance, reno graphy, timed intravenous urography with wash-out test were carried out besides the normal routine tests. Urinary kallikrein was assayed by the PORCELLIet al. [7, 8] method. A sample 24-h collection was kept in toluene at 4~ for not longer than a week for testing the enzyme. Results are expressed in therms of Esterase Units (E.U.) excreted per 24 h. Venous blood samples were taken into heparinized plastic tubes and centrifuged at 0~ at 10,000 g for 10 min, the separated plasma was stored at --20~ until assayed. Plasma DBH activity was measured according to the method of NAGATSUand UDENFRIEND[9]; 1.5 ml of 4 M NH4OH was used to elute the sample from the Dowex W 50 H + columns containing the octopamine according to O6IHA~. et al. [10]. For control of enzymatic dynamics of plasma DBH activity, we observed linear transformation of the substrate between 0 and 20 min at 37~ To each sample of 0.3 ml of human plasma, 0.3 ml of H20 were added and kept on ice; samples of 0.1 ml of mixture were subjected to the Nagatsu method, then incubated for 5, 10, 15 and 20 min. Once enzyme activity was found to be linear with time of incubation, the enzymatic conversion of tyramine to octopamine was measured into International Units (I.U.). Student's t-test and linear regression analyses were performed utilizing statistical techniques. Results
In n o r m a l patients U . K . (Fig. 1) was 20.5 +_ 1.08 E . U . / 2 4 h, in patients with s e c o n d a r y hypertension m e a n values were 33.8 + 3.0, in essential h y p e r t e n s i o n 9.4 -4- 2.0 E . U j 2 4 h (in five o f these patients no e n z y m a t i c activity was found).
Urinary Kallikrein Excretion and Plasma DBH Activity in Hypertension
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Agents and Actions vol. 8/6 (1978) Birkh/iuser Verlag, Basel
Urinary Kallikrein Excretion and Plasma DBH Activity in Hypertension b y A.V. GRECO, G. PORCELLI, J.F. MAGALHAES 1) ~ind L. ALTOMONTE Istituto di Patologia Medica and Istituto di Chimica, Catholic University, Rome, Italy, and Centro Chimica dei Recettori C.N.R., Rome, Italy
Abstract Many factors are to be considered in maintaining normal blood pressure. Authors study the behavior of urinary kailikrein (U;K.) and plasma dopamine-[3hydroxylasc (DBH) activity in varioias forms of hypertension. The values of U.K. excretion in normals were 20.5 + 1.8 E.U./24 h. In essentlal hypertensive patients (9.4 + 2.0 E.U./24 h) U.K. decreased, while in secondary hypertension it was significantly higher (33.8 _+ 3.0 E.U./24 h). Plasma DBH activity in essential hypertensive patients (17.72 + 2.33 I.U./ml) was similar to controls (20.22 _+ 1.39 I.U./ml); in secondary hypertension the mean values of plasma DBH were decreased (12.31 + 2.55 I.U./ml). No correlation between U.K. and plasma DBH activity was observed in normals and in various forms of hypertensive patients. U.K. seems a more reliable factor than plasma DBH in defining the different types of hypertension.
The pathogenesis of h y p e r t e n s i o n is subject to discussion. A p a r t from m a n y extra-renal factors (central n e r v o u s system, a u t o n o m i c nervous system, adrenal h o r m o n e s ) , there is a complicated renal blood pressure regulation syst e m to which belong molecules with a vasoconstrictor action (mostly renin) and, m u c h less studied, molecules with a v a s o d i l a t a t o r action (prostaglandins, kallikrein-kinin system). ELLIOT a n d N u z u M [11], MARGOLZUS et al. [2] a n d GRECO et al. [3] showed that a decrease of u r i n a r y kallikrein (U.K.) o c c u r s in patients with essential hypertension: I n various f o r m s of h y p e r t e n s i o n the blood level of dopamine-fl-hydroxylase ( D B H ) , the enZyme that c o n v e r t s d o p a m i n e to norepinephrine, has b e e n suggested as a satisfactory indicator for diagnosis [4, 5, 6]. 1)Present address:!?Facultade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Brazil.
O u r study was u n d e r t a k e n to define the range of U . K . a n d of p l a s m a D B H activity in diverse types of h y p e r t e n s i o n a n d to d o c u m e n t relative differences between these forms. Methods
58 normal male patients, 19-40 years old, 20 patients with secondary hypertension, 18-60 years old, and 23 essential hypertensive patients, 17-56 years of age, were studied. Before the study, the subjects had not received any drug for at least two weeks and were submitted to a Na+-free diet. Tests of blood creatinine, endogenous clearance, reno graphy, timed intravenous urography with wash-out test were carried out besides the normal routine tests. Urinary kallikrein was assayed by the PORCELLIet al. [7, 8] method. A sample 24-h collection was kept in toluene at 4~ for not longer than a week for testing the enzyme. Results are expressed in therms of Esterase Units (E.U.) excreted per 24 h. Venous blood samples were taken into heparinized plastic tubes and centrifuged at 0~ at 10,000 g for 10 min, the separated plasma was stored at --20~ until assayed. Plasma DBH activity was measured according to the method of NAGATSUand UDENFRIEND[9]; 1.5 ml of 4 M NH4OH was used to elute the sample from the Dowex W 50 H + columns containing the octopamine according to O6IHA~. et al. [10]. For control of enzymatic dynamics of plasma DBH activity, we observed linear transformation of the substrate between 0 and 20 min at 37~ To each sample of 0.3 ml of human plasma, 0.3 ml of H20 were added and kept on ice; samples of 0.1 ml of mixture were subjected to the Nagatsu method, then incubated for 5, 10, 15 and 20 min. Once enzyme activity was found to be linear with time of incubation, the enzymatic conversion of tyramine to octopamine was measured into International Units (I.U.). Student's t-test and linear regression analyses were performed utilizing statistical techniques. Results
In n o r m a l patients U . K . (Fig. 1) was 20.5 +_ 1.08 E . U . / 2 4 h, in patients with s e c o n d a r y hypertension m e a n values were 33.8 + 3.0, in essential h y p e r t e n s i o n 9.4 -4- 2.0 E . U j 2 4 h (in five o f these patients no e n z y m a t i c activity was found).
Urinary Kallikrein Excretion and Plasma DBH Activity in Hypertension
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