Thromboxane and Prostacyclin Production by Irradiated and Perfused Rat Kidney

1. Human plasma was incubated with tissue kallikrein from porcine pancreas, dialysed to obtain a fraction with a molecular mass < 10 kDa and further purified by reverse-phase chromatography. 2. Vasopressor activity in the fractions obtained was tested in the isolated perfused rat kidney. 3. In one fraction a strong vasopressor action was found, which was blocked by saralasin and by an angiotensin II antibody. 4. Aprotinin inhibited the formation of vasopressor substances by tissue kallikrein. 5. U.v.-laser desorption/ionization mass spectrometry revealed a molecular mass of 1046 Da in the purified active fraction. 6. It is concluded that tissue kallikrein forms not only kinins, but also angiotensin II, from human plasma under physiological conditions.

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Comparison of the effects of parathyroid hormone (PTH) and recombinant PTH-related protein on bicarbonate excretion by the isolated perfused rat kidney

Journal of Endocrinology ◽

10.1677/joe.0.1260403 ◽

1990 ◽

Vol 126 (3) ◽

pp. 403-408 ◽

Cited By ~ 27

Author(s):

A. G. Ellis ◽

W. R. Adam ◽

T. J. Martin

Keyword(s):

Parathyroid Hormone ◽

Rat Kidney ◽

Urine Volume ◽

Clinical Manifestations ◽

Fractional Excretion ◽

Bicarbonate Concentration ◽

Isolated Perfused Rat Kidney ◽

Amino Terminal ◽

Fractional Excretion Of Sodium ◽

Perfused Rat Kidney

ABSTRACT The isolated perfused rat kidney was used to study the effects of amino-terminal fragments of human parathyroid hormone, hPTH(1–34), bovine parathyroid hormone, bPTH(1–84) and of PTH-related proteins, PTHrP(1–34), PTHrP(1–84), PTHrP(1–108) and PTHrP(1–141) on urinary bicarbonate excretion. PTHrP(1–34) (7 nmol/l), bPTH(1–84) (5·5 nmol/l) and hPTH(1–34) (7 nmol/l) had similar effects in increasing bicarbonate excretion with respect to the control. At lower concentrations (0·7 nmol/l) all PTHrP components, but not hPTH(1–34) or bPTH(1–84) increased bicarbonate excretion significantly. Infusions of PTHrP(1–108) and PTHrP(1–141) at 0·7 nmol/l, while associated with a rise in urinary bicarbonate concentration and excretion during the early stages of perfusion, produced a sharp decline in bicarbonate concentration and excretion in the latter part of perfusion. The different peptides produced no significant differences in glomerular filtration rate, fractional excretion of sodium or urine volume. The absence of substantial differences between the effects of hPTH(1–34) and PTHrP(1–34) are as noted in previous studies. The differences between PTHrP(1–108)/PTHrP(1–141) and PTHrP(1–34) demonstrated here are consistent with (1) the clinical manifestations of acidosis in hyperparathyroidism and alkalosis in humoral hypercalcaemia of malignancy, and (2) an independent action of a component of PTHrP beyond amino acids 1–34. Journal of Endocrinology (1990) 126, 403–408

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Uptake and release of amino acids by normal and remnant kidneys: studies in the isolated perfused rat kidney

American Journal of Clinical Nutrition ◽

10.1093/ajcn/33.7.1373 ◽

1980 ◽

Vol 33 (7) ◽

pp. 1373-1377 ◽

Cited By ~ 5

Author(s):

G Perez ◽

M Epstein ◽

B Reitberg ◽

C Horton ◽

R Loutzenhiser

Keyword(s):

Amino Acids ◽

Rat Kidney ◽

Isolated Perfused Rat Kidney ◽

Perfused Rat Kidney ◽

Uptake And Release

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Ca-dependent hemodynamic and natriuretic effects of atrial extract in isolated rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.1984.246.4.f447 ◽

1984 ◽

Vol 246 (4) ◽

pp. F447-F456 ◽

Cited By ~ 9

Author(s):

M. J. Camargo ◽

H. D. Kleinert ◽

S. A. Atlas ◽

J. E. Sealey ◽

J. H. Laragh ◽

...

Keyword(s):

Perfusion Pressure ◽

Rat Kidney ◽

Fractional Excretion ◽

Electrolyte Excretion ◽

Renal Vasculature ◽

Filtration Fraction ◽

Perfused Rat Kidney ◽

Site Of Action ◽

Initial Control ◽

Renal Vascular

The effects of rat atrial tissue extract on renal hemodynamics and fluid and electrolyte excretion were investigated in the isolated perfused rat kidney (IK). IK were perfused at a constant effective perfusion pressure of about 90 mmHg. After control clearance periods (C), extracts of rat atria (AE) or ventricles (VE) were added to the perfusate and three 10-min experimental periods followed. AE, but not VE, significantly increased (P less than 0.001) renal vascular resistance (RVR) to 133 +/- 8% of C, GFR to 201 +/- 34%, filtration fraction to 245 +/- 41%, urine flow (V) to 675 +/- 131%, fractional excretion (FE) of H2O to 336 +/- 29%, absolute Na excretion (UNaV) to 1,259 +/- 290%, FENa to 642 +/- 129%, UKV to 2,226 +/- 1,237%, and FEK to 542 +/- 119%. Despite the marked natriuresis, since GFR doubled, Na reabsorption rose from 78.3 +/- 36.3 in C to 132 +/- 36.3 mueq/min after AE. The effects of AE were immediate and lasted to the end of the perfusion. The lower the initial control GFR, the larger was the AE-induced increase in GFR. Perfusion with low [Ca] (0.2 mM) or verapamil (10(-5) M) severely blunted the hemodynamic, diuretic, kaliuretic, and natriuretic effects of AE. AE decreased rather than increased the RVR when IK were perfused with vasoconstrictors such as angiotensin II, norepinephrine, or vasopressin. The results demonstrate that AE acts directly on the kidney, eliciting powerful Ca-dependent hemodynamic and natriuretic responses. The natriuresis induced by AE can be accounted for, at least in part, by its renal hemodynamic effects rather than by the presence of a putative tubular natriuretic factor. The hypothesis is advanced that AE contains a substance(s) which behaves as a functional agonist/antagonist of endogenous vasoconstrictors with a preferential site of action on the efferent arterioles of the renal vasculature.

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