Haemodynamic and Endocrine Responses of the Kidney to Frusemide in Mild Essential Hypertension

1985 ◽  
Vol 68 (2) ◽  
pp. 159-164 ◽  
Author(s):  
I. G. Mackay ◽  
K. Nath ◽  
A. D. Cumming ◽  
A. L. Muir ◽  
M. L. Watson
Keyword(s):  
Glomerular Filtration Rate ◽  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Underlying Factor ◽  
Induced Changes

1. Prostaglandin-dependent, frusemide-induced changes in renal plasma flow, glomerular filtration rate and plasma renin activity were measured in 14 patients with mild essential hypertension. 2. The renal haemodynamic responses to frusemide were the same as in 10 normal subjects. 3. Frusemide-induced changes in urinary PGE and kallikrein excretion were also the same as in normal subjects. 4. Impaired renal release of vasodilator prostaglandins in essential hypertension is likely to be secondary to the hypertension rather than an underlying factor in its development.

γ-l-Glutamyl-l-Dopa is a Dopamine Pro-Drug, Relatively Specific for the Kidney in Normal Subjects

1985 ◽  
Vol 69 (2) ◽  
pp. 207-214 ◽  
Author(s):  
D. P. Worth ◽  
J. N. Harvey ◽  
J. Brown ◽  
M. R. Lee
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Urinary Sodium Excretion ◽  
Systemic Effects

1. γ-l-Glutamyl-l-dopa was given by intravenous infusion to eight normal subjects at doses of 12.5 and 100 μg min−1 kg−1. 2. Both doses of the dipeptide resulted in an increase in mean urinary sodium excretion. 3. Mean effective renal plasma flow rose at both doses, but mean glomerular filtration rate increased only at the lower dose. 4. There was a fall in mean plasma renin activity after the infusion of both 12.5 and 100 μg min−1kg−1. 5. Mean urine free dopamine excretion increased by 280- and 2500-fold at infusion rates of 12.5 and 100 μg min−1 kg−1 respectively. 6. Mean plasma free dopamine rose at both doses but the increase at 12.5 μg min−1 kg−1 was not to a level previously associated with systemic effects of the catecholamine. 7. On administration of the dipeptide at 12.5 μg min−1 kg−1 there were no changes in blood pressure or heart rate, but at the higher dose there was a fall in diastolic blood pressure. 8. At a dose of 12.5 μg min−1 kg−1 in man, there is kidney specific conversion of gludopa to dopamine.

Altered renal response to enhanced endogenous 5-hydroxytryptamine after tryptophan administration in essential hypertension

1992 ◽  
Vol 82 (5) ◽  
pp. 551-557 ◽  
Author(s):  
Fumihiro Tomoda ◽  
Masanobu Takata ◽  
Shinya Oh-Hashi ◽  
Hitoshi Ueno ◽  
Kotaro Yasumoto ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Essential Hypertension ◽  
Urinary Excretion ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Renal Response ◽  
Hypertensive Group ◽  
Normotensive Subjects

1. To examine the pathophysiological significance of 5-hydroxytryptamine (serotonin) in essential hypertension, we compared the renal response to intrarenally formed 5-hydroxytryptamine by oral dosing with its precursor, L-tryptophan (2 g), in nine patients with essential hypertension and in six subjects with normotension. 2. Before tryptophan administration, urinary excretion of 5-hydroxytryptamine was significantly higher in the hypertensive group than in the normotensive group (66 ± 8 versus 36 ± 6 ng/min, P < 0.05), whereas renal plasma flow and glomerular filtration rate did not differ between the two groups. After dosing with tryptophan, urinary excretion of 5-hydroxytryptamine significantly increased to the same plateau level in both groups (366 ± 55 ng/min in the hypertensive group and 365 ± 64 ng/min in the normotensive group). Significant and equivalent decreases in renal plasma flow were observed in the early phase after tryptophan administration in both groups (−8.5 ± 3.4% in the hypertensive group and −8.2 ± 1.7% in the normotensive group). Thereafter, renal plasma flow increased to above the baseline value in normotensive subjects, whereas this late vasodilatation was absent in the hypertensive group. Glomerular filtration rate significantly decreased at the time of the fall in renal plasma flow in the normotensive group (106.8 ± 7.8 to 92.7 ± 8.5 ml min−1 1.73 m−2, P < 0.05), whereas it remained unchanged in the hypertensive group (108.2 ± 6.2 to 110.4 ± 6.3 ml min−1 1.73 m−2, not significant). Consequently, the filtration fraction did not change in normotensive subjects (0.21 ± 0.01 versus 0.19 ± 0.01, not significant), but it increased significantly in the hypertensive group (0.22 ± 0.01 versus 0.26 ± 0.02, P < 0.05). A similar sustained antidiuresis was also observed after tryptophan administration in both groups. In addition, the above-described renal functional changes were not accompanied by any significant changes in systemic blood pressure, the renin-angiotensin-aldosterone system, adrenergic activity or plasma 5-hydroxytryptamine concentration in either group. 3. Our data show that in essential hypertension there is a baseline overproduction of renal 5-hydroxytryptamine, which may contribute to a reduction in renal excretory capability. The altered renal response to tryptophan found in essential hypertension may be partly related to the exaggerated efferent arteriolar constriction induced by endogenously formed 5-hydroxytryptamine.

Renal response to captopril in conscious dogs pretreated with indomethacin

1982 ◽  
Vol 243 (6) ◽  
pp. F543-F548
Author(s):  
Jack M. DeForrest ◽  
Thomas L. Waldron ◽  
Michael J. Antonaccio
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Effective Renal Plasma Flow ◽  
Potassium Excretion ◽  
Captopril Treatment

This study was designed to determine whether the prostaglandins mediate the renal effects of captopril in the conscious sodium-replete dog. In a group of control animals (n = 8), effective renal plasma flow (ERPF) increased from 185 ± 15 to 230 ± 12 ml/min and plasma renin activity (PRA) increased from 0.64 ± 0.15 to 12.9 ± 1.1 ng ANG I·ml-1·h-1 after captopril (10 mg/kg bolus plus 10 μg·kg-1·min-1i.v.) administration. Glomerular filtration rate (GFR) and sodium excretion (UKV) were also increased significantly following captopril treatment, whereas urine volume (V), potassium excretion (UKV), mean arterial pressure (MAP), and heart rate (HR) remained unchanged throughout the experiment. When the same dose of captopril was given to indomethacin-pretreated dogs (5 mg/kg bolus plus 2 μg·kg-1·min-1i.v.), ERPF increased from 170 ± 8 to 265 ± 18 ml/min and PRA increased from 1.2 ± 0.4 to 14.6 ± 3.0 ng ANG I·ml-1·h-11 after the captopril administration. GFR was also increased significantly after captopril, while UNaV, UKV, and V remained unchanged. These data demonstrate that the prostaglandins do not mediate the ability of captopril to increase PRA or effective renal plasma flow in this experimental model. prostaglandins; effective renal blood flow; plasma renin activity; angiotensin II; arachidonic acid Submitted on September 25, 1981 Accepted on June 25, 1982

Clinical Renal Function Testing by External Double Isotope Monitoring Technique

1971 ◽  
Vol 10 (01) ◽  
pp. 16-24
Author(s):  
J. Fog Pedersen ◽  
M. Fog Pedersen ◽  
Paul Madsen
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Correlation Coefficients ◽  
Feedback System ◽  
Effective Renal Plasma Flow ◽  
Advantages And Disadvantages

SummaryAn accurate catheter-free technique for clinical determination simultaneouslyof glomerular filtration rate and effective renal plasma flow by means of radioisotopes has been developed. The renal function is estimated by the amount of radioisotopes necessary to maintain a constant concentration in the patient’s blood. The infusion pumps are steered by a feedback system, the pumps being automatically turned on when the radiation measured over the patient’s head falls below a certain preset level and turned off when this level is again readied. 131I-iodopyracet was used for the estimation of effective renal plasma flow and125I-iothalamate estimation of the glomerular filtration rate. These clearances were compared to the conventional bladder clearances and good correlation was found between these two clearance methods (correlation coefficients 0.97 and.90 respectively). The advantages and disadvantages of this new clearance technique are discussed.

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