Intrarenal Distribution of Plasma Flow in Cirrhosis as Measured by Transit Renography: Relationship with Plasma Renin Activity, and Sodium and Water Excretion

1977 ◽  
Vol 52 (5) ◽  
pp. 469-475 ◽  
Author(s):  
S. P. Wilkinson ◽  
I. K. Smith ◽  
M. Clarke ◽  
V. Arroyo ◽  
J. Richardson ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Free Water ◽  
Plasma Renin ◽  
Renal Perfusion ◽  
Renin Activity ◽  
Water Excretion ◽  
Transit Times ◽  
Abnormal Pattern ◽  
Intrarenal Distribution

1. The intrarenal distribution of plasma flow was determined with a technique based on the analysis of the transit time of sodium o-[131I]-iodohippurate through the kidney in 43 patients with cirrhosis with near-normal total renal perfusion. 2. Twenty-five of the patients had an abnormal pattern of transit times, suggesting a redistribution of plasma flow from outer cortical to juxtamedullary nephrons. 3. Plasma renin activity ranged from below normal to six times normal and high values were found only in patients showing an abnormal pattern of transit times. The latter was also found to be related to sodium retention and a reduced renal capacity to excrete free water.

Plasma renin activity responses to graded decreases in renal perfusion pressure in fetal and newborn lambs

1992 ◽  
Vol 262 (3) ◽  
pp. R524-R529 ◽  
Author(s):  
N. D. Binder ◽  
D. F. Anderson
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Perfusion Pressure ◽  
Plasma Renin ◽  
Renal Perfusion ◽  
Renin Activity ◽  
Renal Perfusion Pressure ◽  
Arterial Blood ◽  
The Right ◽  
The Relationship

We examined the relationship between acute reductions in renal perfusion pressure, as approximated by femoral arterial blood pressure, and plasma renin activity in the uninephrectomized fetal lamb. Renal perfusion pressure was reduced and maintained at a constant value by controlled partial occlusion of the aorta above the renal artery. After 15 min of reduced blood pressure, blood samples were taken for determination of plasma renin activity. This protocol was performed 22 times in 11 fetal lambs. Additionally, three of the fetuses were delivered by cesarean section and studied as newborns for the first week of life. In the fetus, there was a linear relationship between log plasma renin activity and femoral arterial blood pressure (P less than 0.01). After birth, the relationship still existed, although it was shifted to the right (P less than 0.0001). We conclude that there is a significant relationship between plasma renin activity and renal perfusion pressure in the fetal lamb, and as early as 1 day after birth, this relationship shifts to the right in the newborn lamb.

Plasma epinephrine and control of plasma renin activity: possible extrarenal mechanisms

1979 ◽  
Vol 236 (6) ◽  
pp. H854-H859 ◽  
Author(s):  
M. D. Johnson ◽  
E. R. Fahri ◽  
B. R. Troen ◽  
A. C. Barger
Keyword(s):  
Plasma Renin Activity ◽  
Perfusion Pressure ◽  
Potassium Concentration ◽  
Plasma Renin ◽  
Plasma Potassium ◽  
Renal Perfusion ◽  
Renin Activity ◽  
Renal Nerves ◽  
Epinephrine Infusion ◽  
Renal Perfusion Pressure

Previous work from our laboratory has shown that physiological increments of circulating epinephrine concentration increase plasma renin activity (PRA) by an extrarenal beta-receptor mechanism. In the present experiments, epinephrine was infused intravenously at 125 ng.kg-1.min-1 for 45 min in trained, conscious dogs. PRA rose 3 to 5-fold, as previously described, and was accompanied by a transient decline of mean arterial pressure, decreased plasma potassium concentration, and increased hematocrit. Prior splenectomy to maintain hematocrit constant did not attenuate the PRA response to epinephrine. The kidneys of 4 dogs were denervated and constrictor cuff was placed around the renal artery. Renal denervation did not alter the PRA response to intravenous epinephrine infusion. A transient decline in renal perfusion pressure produced by cuff constriction only transiently increase PRA. Neither maintenance of a constant plasma potassium concentration nor oral administration of indomethacin altered the PRA response to epinephrine. We conclude that intravenous epinephrine increases PRA by a mechanism independent of the renal nerves, changes in renal perfusion pressure, hematocrit, plasma potassium concentration, and plasma prostaglandins.

Hepatic Elimination of Renin in Man

1978 ◽  
Vol 55 (4) ◽  
pp. 377-382 ◽  
Author(s):  
B. Hesse ◽  
Ellen Damgaard Andersen ◽  
H. Ring-Larsen
Keyword(s):  
Plasma Renin Activity ◽  
Hepatic Vein ◽  
Plasma Flow ◽  
Control Period ◽  
Elimination Rate ◽  
Plasma Renin ◽  
Extraction Ratio ◽  
Renin Activity ◽  
Hepatic Elimination ◽  
Arterial Plasma

1. Hepatic elimination of renin was measured in 10 well-compensated cardiac patients with normal liver function during a control period and during a period of reduced hepatic plasma flow, induced by physical exercise (seven patients) or intravenous infusion of lysine vasopressin (three patients). 2. Hepatic renin elimination rate (hepatic plasma flow × arterial-hepatic vein difference of plasma renin activity) was found to be linearly correlated with arterial plasma renin activity (r = 0.986, P < 0.001). 3. When hepatic plasma flow fell by 45% the hepatic extraction ratio of renin (arterial-hepatic vein plasma renin activity difference/arterial plasma renin activity) increased by 75%. Hepatic renin clearance (hepatic plasma flow × extraction ratio) remained constant. 4. The results indicate that changes in the hepatic elimination rate of renin do not contribute to changes in plasma renin activity during these events.

Familial Hypertension and Hormonal Profile, Renal Haemodynamics and Body Fluids of Young Normotensive Subjects

1978 ◽  
Vol 55 (s4) ◽  
pp. 367s-371s ◽  
Author(s):  
G. Bianchi ◽  
G. B. Picotti ◽  
G. Bracchi ◽  
D. Cusi ◽  
M. Gatti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Renal Plasma Flow ◽  
Plasma Catecholamines ◽  
Plasma Renin ◽  
Significant Negative Correlation ◽  
Renin Activity ◽  
Compensatory Mechanism ◽  
Normotensive Subjects

1. Almost all the factors that may cause a rise in blood pressure are, in turn, influenced by the increase in blood pressure per se. Thus any primary involvement of one or more of these factors in the pathogenesis of essential hypertension must be evaluated before or during the development of hypertension. 2. Young normotensive subjects both of whose parents are hypertensive have a much higher probability of developing hypertension than those whose parents are both normotensive. 3. The following measurements were made in 56 subjects of the first group (both parents hypertensive) and 35 of the second group (both parents normotensive), matched for age, sex and body surface area: renal plasma flow and glomerular filtration rate, using p-aminohippurate and inulin clearance; 24 h urinary excretion of aldosterone, protein and electrolytes; plasma renin activity; plasma volume. Plasma catecholamines and cardiac index were also measured in 26 subjects of the first group and 25 subjects of the second group using a radioenzymic method and echocardiography. 4. All these factors were similar in the two groups except that renal plasma flow was higher in the first group (767·2 ± 30 versus 650·7 ± 17 ml/min, P < 0·01). Plasma renin activity tended to be lower in subjects with a higher renal plasma flow, but there was no significant negative correlation between the two factors. 5. The possibility that the higher renal plasma flow in subjects with a high probability of developing hypertension is a compensatory mechanism for a primary intrarenal defect is discussed.

Renal Effects of Angiotensin I-Receptor Blockade and Angiotensin Convertase Inhibition in Man

1996 ◽  
Vol 90 (3) ◽  
pp. 205-213 ◽  
Author(s):  
Francois Schmitt ◽  
Svetlozar Natov ◽  
Frank Martinez ◽  
Bernard Lacour ◽  
Thierry P. Hannedouche
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Renal Plasma Flow ◽  
Plasma Renin ◽  
Renin Activity ◽  
Angiotensin Converting Enzyme Inhibition ◽  
Converting Enzyme ◽  
Converting Enzyme Inhibition

1. The objective was to compare two means of inhibition of the renin—angiotensin system [angiotensin-converting enzyme inhibition and selective antagonism of angiotensin II subtype 1 (AT1) receptor] on renal function in 10 healthy normotensive volunteers on a normal sodium diet. Since mechanisms of action may differ between both drugs, a synergistic action was further studied by combining the two drugs. 2. The design was a double-blind randomized acute administration of either placebo or a single oral dose of enalapril, 20 mg, followed in each case by administration of the AT1 selective antagonist losartan potassium, 50 mg orally. 3. The methods included measurements of hormones (plasma renin activity, plasma aldosterone), blood pressure and renal function from 45 to 135 min after administration of placebo or enalapril, and from 45 to 135 min after losartan and placebo or losartan and enalapril. Renal function was studied using clearance of sodium, lithium, uric acid, inulin and para-aminohippuric acid. To examine further the determinants of glomerular filtration at the microcirculation level, fractional clearance of neutral dextran was determined and sieving curves were applied on a hydrodynamic model of ultrafiltration. 4. Losartan did not change plasma renin activity, blood pressure or glomerular filtration rate, but increased significantly renal plasma flow and urinary excretion of sodium and uric acid. Enalapril increased plasma renin activity and renal plasma flow, and decreased blood pressure without natriuretic, lithiuretic or uricosuric effects. The renal vasodilatation was potentiated when losartan and enalapril were combined, despite a further rise in plasma renin. In contrast to enalapril, losartan either alone or in combination with enalapril significantly depressed fractional clearances of dextran of small radii (34–42 Å). These changes in fractional clearances of dextran were presumably related to the rise in glomerular plasma flow since the other major determinants of filtration, i.e. transcapillary glomerular pressure gradient, ultrafiltration coefficient and membrane property, were computed as unchanged by either losartan, enalapril or a combination of both. 5. In conclusion, these findings suggest that in normal sodium-repleted man the renal, hormonal and blood pressure effects of AT1 antagonism and angiotensin-converting enzyme inhibition are not strictly similar and could be synergistic.

Plasma renin activity, vasopressin concentration, and urinary excretory responses to exercise in men

1980 ◽  
Vol 49 (6) ◽  
pp. 930-936 ◽  
Author(s):  
C. E. Wade ◽  
J. R. Claybaugh
Keyword(s):  
Plasma Renin Activity ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Plasma Osmolality ◽  
Free Water ◽  
Plasma Renin ◽  
Renin Activity ◽  
Work Intensity ◽  
Vasopressin Release ◽  
Plasma Lactate Concentration

Plasma vasopressin concentration (PAVP), renal function, and effectors of vasopressin release were evaluated in male volunteers during running at heart rates of 0, 35, 70, and 100% of maximum after 10 h abstinence from water (normal hydration) and at 100% after ingestion of 300 ml water. Plasma renin activity (PRA) and PAVP were linearly correlated and correlated to work intensity over all observations. Changes in PAVP were not correlated with changes in plasma osmolality (POSMOL) and plasma volume (PV) over all observations. Furthermore, despite similar changes in POSMOL, PV, PRA, body weight, mean arterial pressure, and plasma lactate concentration, the increase in PAVP after maximal exercise was greater during normal hydration than the water-supplemented state. Decreased urine flow observed in association with exercise was characterized by increased free water and decreased osmotic and creatinine clearances. Thus increased PAVP associated with exercise appears not to play a role in the concomitant antidiuresis. Vasopressin stimuli are probably variable at different times during exercise and may include factors other than those measured.

Urinary Kallikrein and Plasma Renin during the Reversal of Renovascular Hypertension in Rats

1976 ◽  
Vol 51 (s3) ◽  
pp. 263s-266s
Author(s):  
O. P. Gulati ◽  
O. A. Carretero ◽  
T. Morino ◽  
N. B. Oza
Keyword(s):  
Plasma Renin Activity ◽  
Renal Artery ◽  
Renovascular Hypertension ◽  
Sodium Excretion ◽  
Plasma Renin ◽  
Renin Activity ◽  
Experimental Hypertension ◽  
Urinary Kallikrein ◽  
Sodium Potassium ◽  
Water Excretion

1. Urinary kallikrein, sodium, potassium and water excretion, and plasma renin activity were measured before and during the reversal of experimental hypertension produced by unclamping the renal artery in rats. 2. Kallikrein excretion decreased significantly after unclamping, suggesting that it does not play a significant role in the reversal of hypertension. 3. A decrease in plasma renin activity coupled with a slight increase of sodium excretion was observed, indicating that these might participate in the reversal of hypertension.

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