The Patterns of Renal Electrolyte Excretion in the Duck (Anas Platyrhynchos) Maintained on Freshwater and on Hypertonic Saline

1968 ◽  
Vol 48 (3) ◽  
pp. 487-508
Author(s):  
W. N. HOLMES ◽  
G. L. FLETCHER ◽  
D. J. STEWART
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Hypertonic Saline ◽  
Plasma Flow ◽  
Inorganic Phosphate ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Urine Flow ◽  
Electrolyte Excretion

1. The renal excretion of water and electrolytes was examined in starved ducks maintained on fresh water and on hypertonic saline containing 284 mM/1. NaCl and 6.0 mM/l. KCl. 2. No significant differences were observed in the urine flow, glomerular filtration rate, renal plasma flow and the excretory rates of K+, NH4+ and inorganic phosphate between these two groups of birds. 3. The excretory rates of Na+, Cl- and Ca2+ were significantly higher in saline-maintained birds than in the freshwater-maintained birds. 4. NH4+ appeared to be a major cationic component which occupied over half of the available osmotic space in the urine of both the freshwater-maintained and saline-maintained birds. 5. In saline-maintained birds the excretion of K+ and inorganic phosphate appeared to be independent of the available osmotic space in the urine whereas the excretion of Na+ and Cl- appeared to be very dependent upon this factor. 6. These observations suggest that the kidneys of the saline-maintained bird constitute the primary pathway for the excretion of K+, NH4+ and inorganic phosphate, and that with respect to the excretion of Na+ they constitute a relatively minor pathway.

Renal Excretion of l-Epinephrine in the Dog

1958 ◽  
Vol 193 (2) ◽  
pp. 371-374 ◽  
Author(s):  
Richard T. Jones ◽  
William D. Blake
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Blocking Agent ◽  
Tubular Secretion ◽  
Sodium Pentobarbital ◽  
Tubular Transport

The renal excretion of epinephrine was studied in dogs anesthetized with sodium pentobarbital. Epinephrine in plasma and urine was quantitatively estimated by the fluorometric method of Lund. Glomerular filtration rate (creatinine clearance), renal plasma flow (PAH clearance) and PAH transport were employed as parameters of renal function. During periods of intravenous infusion of epinephrine, the percentage of hormone excreted was about 4.6% of that infused. The renal clearance of epinephrine was significantly greater than the glomerular filtration rate though less than renal plasma flow. From this and other information it was concluded that epinephrine is excreted both by tubular transport (tubular secretion) and glomerular filtration. The tubular transport of epinephrine was not inhibited by either 2,4-dinitrophenol or an adrenergic blocking agent.

Effects of X-Irradiation on Renal Function of Rats

1957 ◽  
Vol 188 (2) ◽  
pp. 367-370 ◽  
Author(s):  
L. H. Smith ◽  
W. R. Boss
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Flow ◽  
Whole Body ◽  
Irradiation Damage ◽  
X Rays

In a study of the direct effects of irradiation on the renal function of rats whose exteriorized kidneys were exposed to massive doses of x-rays, significant augmentation of the urine flow was observed 28 days after 2500 r. On the 7th day after 2500, 3000 and 4000 r the urine flow was slightly above that of control rats. The glomerular filtration rate was enhanced on the 7th day after 2500 and 3000 r. Conversely, 28 days after these x-ray doses the filtration rate was slightly below the control values. In the 4000-r, 28-day group, the glomerular filtration rate was 43% below that of the controls. No significant changes in the renal plasma flow occurred on the 7th day after 2500, 3000 and 4000 r. An insignificant increase in the renal plasma flow was noted 28 days after 2500 and 3000 r. On the 28th day after 4000 r, however, the renal plasma flow was 51% below that of the controls. We concluded that both augmentation and depression of renal function were the result of the direct action of x-rays on the kidneys. The results also suggest that renal failure resulting from direct irradiation damage to the kidneys is not a major factor that contributes to deaths occurring within 7 days after the exposure of rats to 4000 r or less of whole-body x-rays.

DIE RENALE CLEARANCE DES ALDOSTERONS UND SEINER HAUPTMETABOLITE BEIM MENSCHEN

1965 ◽  
Vol 49 (4) ◽  
pp. 510-524 ◽  
Author(s):  
J. Gfeller ◽  
W. Siegenthaler
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Clearance ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Flow ◽  
Order Of Magnitude ◽  
Renale Clearance

ABSTRACT Metabolism and excretion of aldosterone in six normal persons were investigated with the renal clearance method. At normal levels of urine flow (0.5–1.2 ml/min), the reabsorption of free aldosterone in the kidney is 90–95 %, ranging thus in the same order of magnitude as the reabsorption of cortisol. The average clearance of the 3-oxo-conjugate exceeds renal plasma flow by 70 %. Therefore it can be assumed that free aldosterone is converted to the 3-oxo-conjugate by the kidney. The renal clearance of the tetrahydroaldosterone glucuronide was on the average 138 % of the thiosulfate clearance or glomerular filtration rate. The concept of renal clearance properly used cannot be applied to the excretion of the metabolites of aldosterone which apparently are produced to some extent by the kidneys themselves.

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.

Influence of nifedipine on cyclosporin A nephrotoxicity after unilateral nephrectomy in the spontaneously hypertensive rat

1991 ◽  
Vol 81 (2) ◽  
pp. 271-279 ◽  
Author(s):  
P. G. McNally ◽  
F. Baker ◽  
N. Mistry ◽  
J. Walls ◽  
J. Feehally
Keyword(s):  
Body Weight ◽  
Glomerular Filtration Rate ◽  
Renal Impairment ◽  
Cyclosporin A ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Denervation ◽  
Renal Plasma Flow ◽  
Spontaneously Hypertensive

1. Nifedipine ameliorates cyclosporin A-induced renal impairment in surgically intact (two-kidney) rats. This study investigates the effect of nifedipine on cyclosporin A nephrotoxicity in spontaneously hypertensive rats after either uninephrectomy or uninephrectomy with contralateral renal denervation. 2. Fourteen days after uninephrectomy pair-fed rats were injected for 14 days with cyclosporin A (25 mg/kg body weight) via the subcutaneous route and with nifedipine (0.1 mg/kg body weight) via the intraperitoneal route. Renal and systemic haemodynamics were measured in conscious unrestrained rats. 3. Whole-blood levels of cyclosporin A did not differ between groups (overall 352 ± 22 ng/ml, means ± sem). After uninephrectomy, cyclosporin A decreased the glomerular filtration rate (olive oil versus cyclosporin A: 0.96 ± 0.04 versus 0.70 ± 0.06 ml min−1 100 g body weight, P < 0.02) and effective renal plasma flow (1.94 ± 0.10 versus 1.38 ± 0.13, P < 0.01), and increased renal vascular resistance {(20.2 ± 1.8) × 104 versus (31.6 ± 3.3) × 104 kPa l−1 s [(20.2 ± 1.8) × 103 versus (31.6 ± 3.3) × 103 dyn s cm−5], P < 0.02} and mean arterial pressure (146.7 ± 6.7 versus 167.3 ± 2.9 mmHg, P < 0.05). Neither renal denervation nor nifedipine prevented the reduction in glomerular filtration rate or effective renal plasma flow induced by cyclosporin A. 4. This study infers that the sympathetic nervous system does not play an active role in cyclosporin A nephrotoxicity and demonstrates that the concomitant administration of nifedipine to rats with reduced renal mass does not ameliorate cyclosporin A-induced renal impairment.

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