COMPARATIVE EXPERIMENTS ON THE URINARY EXCRETION OF EXOGENOUS OXYTOCIN AND VASOPRESSIN

1973 ◽  
Vol 73 (4) ◽  
pp. 643-650 ◽  
Author(s):  
Svend Erik Jensen ◽  
Per Frandsen ◽  
Aage Theil Nielsen
Keyword(s):  
Steady State ◽  
Urinary Excretion ◽  
Continuous Infusion ◽  
Glomerular Filtration ◽  
Blood Level ◽  
Intravenous Injection ◽  
Arginine Vasopressin ◽  
Plasma Proteins ◽  
Renal Handling ◽  
Collecting Ducts

ABSTRACT The urinary excretion of oxytocin (milk-ejecting activity) and arginine vasopressin (antidiuretic activity) in water-loaded rabbits was measured following simultaneous intravenous injection of 1–9 IU of oxytocin and 0.1–0.3 IU of vasopressin per animal. The percentage excretion of vasopressin was 2–10 times that of oxytocin. Experiments with a steady state blood level of vasopressin and oxytocin maintained by continuous infusion showed, that the vasopressin/oxytocin ratio increased 2–6 times, when the hormones passed from the blood into the urine. This indicates a difference in the renal handling of the hormones with regard to the mechanism of the urinary excretion. The urinary clearance of vasopressin was about the same as that of inulin, consistent with the hypothesis, that vasopressin is excreted mainly by glomerular filtration. The clearance of oxytocin was lower than that of vasopressin and inulin, indicating that oxytocin is filtered at a lower rate (binding to plasma proteins) or partly re-absorbed or inactivated in the tubules and/or collecting ducts.

Renal Handling of Lithium and the Effects of Mannitol and Arginine Vasopressin in man

1995 ◽  
Vol 89 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Faruq H. Noormohamed ◽  
Ariel F. Lant
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Flow Rate ◽  
Arginine Vasopressin ◽  
Filtration Rate ◽  
Free Water ◽  
Fractional Excretion ◽  
Renal Handling ◽  
Fractional Clearance ◽  
Induced Changes

1. A study has been undertaken in six healthy male subjects to clarify whether post-proximal segments of the nephron contribute to the renal handling of lithium under conditions of maximal forced osmotic load diuresis and arginine vasopressin-induced antidiuresis. Increments in the fractional clearance of free water, as a measure of effect at the proximal tubule, were positively correlated with incremental changes in flow rate, factored for glomerular filtration rate (mean r = 0.80 ± 0.12, P < 0.001), and fractional excretion of lithium (mean r = 0.84 ± 0.06, P < 0.001). Changes in flow rate and fractional excretion of lithium were also closely correlated with one another (mean r = 0.81 ± 0.06, P < 0.001), and the mean slope of these regression lines was not significantly different from unity (1.18; 95% confidence interval 0.76–1.59). These results show that, under conditions of maximal hydration, mannitol-induced changes in proximal tubular function were closely correlated with induced changes in the fractional excretion of lithium. 2. Infusion of arginine vasopressin alone (0.5 m-units/min) caused a marked reduction in both fractional clearance of free water (10.7% ± 1.2% to −1.2% ± 0.2%, P < 0.001) and flow rate factored for glomerular filtration rate (14.0 ± 1.5 to 0.8 ± 0.2%; P < 0.001) while the fractional excretion of lithium showed only a small non-significant decrease (25.3% ± 2.0% to 23.3% ± 2.2%). A similar dissociation was noted between fluid and lithium excretion when arginine vasopressin was superimposed on mannitol infusion with reductions in the fractional clearance of free water (12.7% ± 1.0% to −0.9% ± 0.7%, P < 0.001) and flow rate (18.6% ± 1.5% to 5.7% ± 1.0%; P < 0.001), while the fractional excretion of lithium showed a significant increase (28.4% ± 1.7% to 33.1% ± 2.4%; P < 0.05). The lack of correlation between fluid and lithium excretion, in the presence of arginine vasopressin with or without mannitol, indicates that the late distal tubule and collecting duct have little or no significant capacity to reabsorb lithium. 3. These findings, taken as a whole, strengthen the view that renal tubular handling of lithium is primarily a proximal event.

Effect of 25(OH)vitamin D3 on urinary excretion of cyclic adenosine monophosphate

1975 ◽  
Vol 229 (4) ◽  
pp. 907-910 ◽  
Author(s):  
MM Popovtzer ◽  
JB Robinette
Keyword(s):  
Urinary Excretion ◽  
Continuous Infusion ◽  
Vitamin D3 ◽  
Cyclic Adenosine Monophosphate ◽  
Fractional Excretion ◽  
Adenosine Monophosphate ◽  
Renal Handling ◽  
Control Value ◽  
Group 1 ◽  
Intact Rats

To further evaluate the effect of 25(OH)vitamin D3 (25(OH)vit D3) on renal handling of phosphorus, fractional excretion of phosphorus (CP/CIn) and urinary excretion of cyclic AMP (UcAMP) were measured in the following groups of animals: 1) intact rats receiving intravenously 25(OH)vit D3. 2a) Parathyroidectomized (PTX) rats receiving a continuous infusion of parathyroid hormone (PTH). 2b) PTX rats undergoing continuous infusion of PTH and receiving intravenously 25(OH)vit D3. In group 1 a decrease in CP/CIn from a control value of 0.210 +/- 0.064 (kappa +/- SE) to 0.052 +/- 0.017 (P less than 0.001) during 25(OH)vit D3 infusion was associated with a corresponding decrease in UcAMP from 182 +/- 18 to 87 +/- 8 pmol/min (P less than 0.001). In group 2a an increase in CP/CIn from a control value of 0.031 +/- 0.014 to 0.365 +/- 0.017 during PTH infusion was associated with a corresponding increase in UcAMP from 76 +/- 17 to 330 +/- 51 pmol/min (P less than 0.001). In group 2b a decrease in CP/CIn from 0.365 +/- 0.017 to 0.256 +/- 0.011 (P less than 0.01) during 25(OH)vit D3 infusion was associated with a decrease in UcAMP from 356 +/- 63 to 191 +/- 33 pmol/min (P less than 0.01). These results indicate that the blunting of the phosphaturic response to PTH by 25(OH)vit D3 is associated with a decrease in UcAMP. This observation suggests that the mechanism underlying the enhanced tubular reabsorption of phosphorus is inhibition of the PTH-induced activation of adenylate cyclase in the kidney.

Placental Transfer of Calcium and Strontium in the Rat and Rabbit

1957 ◽  
Vol 189 (1) ◽  
pp. 91-97 ◽  
Author(s):  
R. H. Wasserman ◽  
C. L. Comar ◽  
M. M. Nold ◽  
F. W. Lengemann
Keyword(s):  
Steady State ◽  
Urinary Excretion ◽  
Fetal Development ◽  
Placental Transfer ◽  
Maternal Diet ◽  
Late Pregnancy ◽  
Placental Barrier ◽  
Tracer Techniques ◽  
Comparative Metabolism ◽  
Differential Movement

The comparative metabolism of calcium and strontium during fetal development was investigated in rats and rabbits using double tracer techniques. In general, the placental transfer from dam to fetus of strontium was about one-half that of calcium; the site of discrimination was the placental barrier. The major discrimination occurred in movement of Ca* and Sr* from dam to fetus, with little or no differential movement from fetus to dam. Under steady state conditions in the rat the relative Sr*/Ca* ratios in the fetus, maternal skeleton and diet were 0.17, 0.28 and 1, respectively. The over-all discrimination of 0.17 between fetus and diet resulted from absorption (0.42), urinary excretion (0.63) and placental transfer (0.65). In the rat it was estimated that 92% of the fetal calcium had originated from the maternal diet. In the rabbit during late pregnancy, it was determined that about 24 mg of calcium/fetus/day moved across the placenta as compared with a need of about 13 mg for fetal development.

scholarly journals Response of cortical collecting ducts from remnant kidneys to arginine vasopressin

1992 ◽  
Vol 41 (5) ◽  
pp. 1150-1154 ◽  
Author(s):  
Melvin Bonilla-Felix ◽  
L. Lee Hamm ◽  
John Herndon ◽  
V. Matti Vehaskari
Keyword(s):  
Arginine Vasopressin ◽  
Collecting Ducts

Drug Interactions with Warfarin: Studies with Dichloralphenazone, Chloral Hydrate and Phenazone (Antipyrine)

1971 ◽  
Vol 40 (4) ◽  
pp. 351-364 ◽  
Author(s):  
A. Breckenridge ◽  
M. L'E. Orme ◽  
S. Thorgeirsson ◽  
D. S. Davies ◽  
R. V. Brooks
Keyword(s):  
Endoplasmic Reticulum ◽  
Steady State ◽  
Urinary Excretion ◽  
Binding Sites ◽  
Half Life ◽  
Chloral Hydrate ◽  
Maximal Velocity ◽  
Protein Binding Sites ◽  
Drug Oxidation ◽  
State Plasma

1. Administration of dichloralphenazone, a complex of chloral hydrate and phenazone (antipyrine) caused a fall in steady-state plasma warfarin concentration and loss of anticoagulant control in five subjects. 2. This effect of dichloralphenazone is due to stimulation of the drug-oxidizing enzymes of the liver endoplasmic reticulum by antipyrine, the non-hypnotic part of the complex. Administration of antipyrine caused a fall in steady-state plasma warfarin concentration in five subjects, a shortening of the plasma warfarin half-life, with increased urinary excretion of the metabolites of 14C-labelled warfarin in two subjects and increased urinary excretion of 6β-hydroxycortisol which is formed in the liver endoplasmic reticulum. 3. Administration of chloral hydrate, the hypnotic part of dichloralphenazone, caused no change in anticoagulant control but a fall in steady-state plasma warfarin concentration in five subjects. This is due to the accumulation of trichloroacetic acid which displaces warfarin from plasma protein binding sites. 4. Individual differences in the extent of enzyme induction have been shown to be related to the subjects' rates of drug oxidation. 5. In the rat administration of dichloralphenazone and antipyrine, but not chloral hydrate, caused shortening of pentobarbitone sleeping time and of the plasma [14C]pentobarbitone half-life, shortening of the zoxazolamine paralysis time and increase in the maximal velocity of N-demethylation of ethylmorphine.

scholarly journals Role of Klotho in Hyperglycemia: Its Levels and Effects on Fibroblast Growth Factor Receptors, Glycolysis, and Glomerular Filtration

2021 ◽  
Vol 22 (15) ◽  
pp. 7867
Author(s):  
Marlena Typiak ◽  
Tomasz Kulesza ◽  
Patrycja Rachubik ◽  
Dorota Rogacka ◽  
Irena Audzeyenka ◽  
...  
Keyword(s):  
Growth Factor ◽  
Urinary Excretion ◽  
Glomerular Filtration ◽  
Fibroblast Growth Factor ◽  
Growth Factor Receptors ◽  
Renal Tissue ◽  
Proper Function ◽  
Fibroblast Growth ◽  
Fibroblast Growth Factor Receptors ◽  
Plasma Filtration

Hyperglycemic conditions (HG), at early stages of diabetic nephropathy (DN), cause a decrease in podocyte numbers and an aberration of their function as key cells for glomerular plasma filtration. Klotho protein was shown to overcome some negative effects of hyperglycemia. Klotho is also a coreceptor for fibroblast growth factor receptors (FGFRs), the signaling of which, together with a proper rate of glycolysis in podocytes, is needed for a proper function of the glomerular filtration barrier. Therefore, we measured levels of Klotho in renal tissue, serum, and urine shortly after DN induction. We investigated whether it influences levels of FGFRs, rates of glycolysis in podocytes, and albumin permeability. During hyperglycemia, the level of membrane-bound Klotho in renal tissue decreased, with an increase in the shedding of soluble Klotho, its higher presence in serum, and lower urinary excretion. The addition of Klotho increased FGFR levels, especially FGFR1/FGFR2, after their HG-induced decrease. Klotho also increased levels of glycolytic parameters of podocytes, and decreased podocytic and glomerular albumin permeability in HG. Thus, we found that the decrease in the urinary excretion of Klotho might be an early biomarker of DN and that Klotho administration may have several beneficial effects on renal function in DN.

Measurement of leucine metabolism in man from a primed, continuous infusion of L-[1-3C]leucine

1980 ◽  
Vol 238 (5) ◽  
pp. E473-E479 ◽  
Author(s):  
D. E. Matthews ◽  
K. J. Motil ◽  
D. K. Rohrbaugh ◽  
J. F. Burke ◽  
V. R. Young ◽  
...  
Keyword(s):  
Steady State ◽  
Continuous Infusion ◽  
Co2 Production ◽  
Human Beings ◽  
Priming Dose ◽  
Leucine Metabolism ◽  
Kinetics Of ◽  
13Co2 Enrichment

Leucine metabolism in vivo can be determined from a primed, continuous infusion of L-[1-13C]leucine by measuring, at isotopic steady state, plasm [-13C]leucine enrichment, expired 13CO2 enrichment, and CO2 production rate. With an appropriate priming dose of L-[1-13C]leucine and NaH13CO3, isotopic steady state is reached in less than 2 h, and the infusion is completed in 4 h. The method can determine rates of leucine turnover, oxidation, and incorporation into protein with typical relative uncertainties of 2, 10, and 4%, respectively. The method requires no more than 1 ml of blood and uses stable isotope rather than radioisotope techniques. Thus, the method is applicable to studies of human beings of all ages. L-[1-13C]leucine may be infused with a second amino acid labeled with 15N for simultaneous determination of the kinetics of two amino acids.

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