Single nephron function during prolactin-induced pseudopregnancy in the rat

1985 ◽  
Vol 107 (1) ◽  
pp. 127-131 ◽  
Author(s):  
J. Walker ◽  
H. O. Garland
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Filtration Rate ◽  
Treated Group ◽  
Female Rats ◽  
Fluid Reabsorption ◽  
Single Nephron ◽  
Renal Changes ◽  
Proximal Tubular ◽  
Renal Micropuncture

ABSTRACT Whole kidney and renal micropuncture techniques were used to investigate the effects of chronic prolactin treatment on kidney function in anaesthetized female rats. At the whole kidney level, glomerular filtration rate (GFR) and fluid reabsorption were both significantly (P<0·02) increased in the hormone-treated group. At the single nephron level, GFR and proximal fluid reabsorption were also increased (P<0·05) by prolactin treatment. Fractional reabsorption was also enhanced at the proximal tubular level in hormone-treated animals. Such changes in renal function are similar to those seen in rat pregnancy and cervically stimulated pseudopregnancy. Since circulating prolactin concentrations are increased in both reproductive states, the hormone may play an important role in establishing the characteristic renal changes seen therein. J. Endocr. (1985) 107, 127–131

scholarly journals Nephron filtration rate and proximal tubular fluid reabsorption in the Akita mouse model of type I diabetes mellitus

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 83 ◽  
Author(s):  
Jurgen Schnermann ◽  
Mona Oppermann ◽  
Yuning Huang
Keyword(s):  
Diabetes Mellitus ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Type I Diabetes ◽  
Type I ◽  
Fluid Reabsorption ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Tubular Fluid Reabsorption

An increase of glomerular filtration rate (hyperfiltration) is an early functional change associated with type I or type II diabetes mellitus in patients and animal models. The causes underlying glomerular hyperfiltration are not entirely clear. There is evidence from studies in the streptozotocin model of diabetes in rats that an increase of proximal tubular reabsorption results in the withdrawal of a vasoconstrictor input exerted by the tubuloglomerular feedback (TGF) mechanism. In the present study, we have used micropuncture to assess single nephron function in wild type (WT) mice and in two strains of type I diabetic Ins2+/- mice in either a C57Bl/6 (Akita) or an A1AR-/- background (Akita/A1AR-/-) in which TGF is non-functional. Kidney glomerular filtration rate (GFR) of anesthetized mice was increased by 25% in Akita mice and by 52% in Akita/A1AR-/-, but did not differ between genotypes when corrected for kidney weight. Single nephron GFR (SNGFR) measured by end-proximal fluid collections averaged 11.8 ± 1 nl/min (n=17), 13.05 ± 1.1 nl/min (n=23; p=0.27), and 15.4 ± 0.84 nl/min (n=26; p=0.009 compared to WT; p=0.09 compared to Akita) in WT, Akita, and Akita/A1AR-/- mice respectively. Proximal tubular fluid reabsorption was not different between WT and diabetic mice and correlated with SNGFR in all genotypes. We conclude that glomerular hyperfiltration is a primary event in the Akita model of type I diabetes, perhaps driven by an increased filtering surface area, and that it is ameliorated by TGF to the extent that this regulatory system is functional.

Feedback mediation of SNGFR autoregulation in hydropenic and DOCA- and salt-loaded rats

1979 ◽  
Vol 237 (1) ◽  
pp. F63-F74 ◽  
Author(s):  
L. C. Moore ◽  
J. Schnermann ◽  
S. Yarimizu
Keyword(s):  
Glomerular Filtration Rate ◽  
Arterial Pressure ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Tubuloglomerular Feedback ◽  
Single Nephron ◽  
Proximal Tubular

Tubuloglomerular feedback (TGF) mediation of autoregulation was investigated by measuring the response of single nephron glomerular filtration rate (SNGFR) to changes in arterial pressure (AP) following acute or chronic TGF inhibition. In hydropenic rats with intact TGF, distal SNGFR was 25.0 +/- 1.2 (SE) and 23.9 +/- 1.4 nl/min at AP of 111 and 135 mmHg, respectively. In the same 20 nephrons during proximal tubular microinfusion of furosemide, distal SNGFR was 23.6 +/- 1.4 (n = 16) and 29.7 +/- 1.4 nl/min (n = 20) (P less than 0.001, n = 16) at 112 and 133 mmHg. When determined proximally, SNGFR was 25.6 +/- 1.0 and 29.5 +/- 0.9 nl/min (P less than 0.001, n = 31) at 112 and 157 mmHg; kidney GFR increased similarly. These data and the predictions of a GFR model were then used to estimate autoregulatory efficiency. This analysis indicated that partial autoregulation occurred during TGF inhibition. Therefore, TGF is an essential, but probably not the only, mechanism mediating SNGFR autoregulation.

Micropuncture study of avian kidney: effect of prolactin

1992 ◽  
Vol 262 (5) ◽  
pp. R933-R937 ◽  
Author(s):  
J. R. Roberts ◽  
W. H. Dantzler
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Slight Reduction ◽  
Plasma Parameters ◽  
Single Nephron ◽  
Ovine Prolactin ◽  
Fractional Excretion Of Phosphate

Renal function was studied in anesthetized European starlings (Sturnis vulgaris) by micropuncture and clearance techniques. A previous study had shown some changes in the renal function of birds in molt. Endogenous prolactin levels have been shown to be elevated at this time. In the present study, renal function was studied during the infusion of an isotonic sodium chloride solution and then when ovine prolactin was added to the infusion. Ovine prolactin resulted in an elevation of plasma urate concentration but had no significant effects on other plasma parameters or on the concentration of the various ions in tubular fluid samples. Urine flow rate was significantly higher during prolactin infusion, although whole animal glomerular filtration rate, single nephron glomerular filtration rate, and the percentage fluid reabsorption in the proximal tubule (up to the point of micropuncture) were unaltered. The whole animal fractional excretions of sodium and chloride were significantly higher, those of magnesium and potassium were significantly lower, and the fractional excretion of phosphate tended to be lower during prolactin infusion. At the level of the proximal tubules of the reptilian-type nephrons, prolactin infusion caused a slight reduction in the net reabsorption of sodium and chloride. Therefore the main effects of prolactin on renal function are occurring in the distal nephron of the reptilian-type nephrons or in the mammalian-type nephrons. It appears that prolactin may affect renal function in avian species and that these actions may be modulated by a range of factors as has been demonstrated in mammals.

Head-down tilt and restraint on renal function and glomerular dynamics in the rat

1987 ◽  
Vol 63 (2) ◽  
pp. 505-513 ◽  
Author(s):  
B. J. Tucker ◽  
C. A. Mundy ◽  
M. G. Ziegler ◽  
C. Baylis ◽  
R. C. Blantz
Keyword(s):  
Renal Function ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Extracellular Volume ◽  
Extracellular Fluid ◽  
Conscious Rats ◽  
Single Nephron ◽  
Volume Measurements ◽  
Renal Micropuncture ◽  
Glomerular Ultrafiltration

A model utilizing 25 degree head-down tilt (HDT) and incorporated with chronic catheterization and renal micropuncture techniques in rats was employed to study alterations in renal function induced by HDT. Renal function and extracellular volume measurements were performed after 24 h, 4 days, and 7 days of HDT in conscious rats and compared with their own control measurements and to nontilted but similarly restrained rats. After 24 h HDT, glomerular filtration rate (GFR) increased 19 +/- 8% and renal plasma flow (RPF) increased 18 +/- 8% with increases in urine flow rate, Na+, and K+ excretion in conscious rats. These increases after 24 h were associated with an increase in extracellular volume of 16 +/- 3% (P less than 0.01). In the nontilted controls, there was a decrease in extracellular volume after 24 h of suspension. After 7 days of HDT, GFR was decreased by 7 +/- 1% (P less than 0.01), but RPF and extracellular fluid volume were not different from control values. However, RPF and GFR increased in the nontilted rats after 7 days. After 7 days of HDT renal micropuncture studies demonstrated that single-nephron filtration rate was also decreased from 43 +/- 2 to 31 +/- 3 nl/min (P less than 0.05) due solely to reductions in the glomerular ultrafiltration coefficient (0.11 +/- 0.01 to 0.07 +/- 0.01 nl.s-1 X mmHg-1, P less than 0.05). There was a dissociation between GFR and water and Na+ excretion at days 4 and 7 of HDT not observed in the nontilt restraint controls.

A Micropuncture Study of Proximal Tubular Function after Acute Hydrochlorothiazide Administration to Brattleboro Rats with Diabetes Insipidus

1979 ◽  
Vol 57 (5) ◽  
pp. 427-434 ◽  
Author(s):  
S. J. Walter ◽  
J. F. Laycock ◽  
D. G. Shirley
Keyword(s):  
Glomerular Filtration Rate ◽  
Diabetes Insipidus ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Inhibitory Effect ◽  
Tubular Reabsorption ◽  
Brattleboro Rats ◽  
Fluid Reabsorption ◽  
Proximal Tubular ◽  
Proximal Tubular Reabsorption

1. Renal function in anaesthetized Brattleboro rats with hereditary hypothalamic diabetes insipidus was studied with micropuncture techniques before, and 1–3 h after, a single injection of hydrochlorothiazide. 2. In rats given hydrochlorothiazide and kept in sodium and water balance, total glomerular filtration rate and superficial nephron filtration rate were similar to values in control animals, whereas fractional fluid reabsorption in the proximal tubule (as evidenced by tubular fluid/plasma inulin concentration ratios) was slightly, but significantly, reduced. This suggests that hydrochlorothiazide may have a small direct inhibitory effect on proximal tubular reabsorption. 3. When rats were given hydrochlorothiazide and the resultant extra urinary sodium losses were not replaced, there was a marked antidiuresis. In these animals total glomerular filtration rate was reduced by 23% and superficial nephron filtration rate by 27% when compared with values in control rats. Fractional proximal tubular fluid reabsorption increased significantly whereas absolute proximal fluid reabsorption was unaffected. 4. It is concluded that the reduction in body sodium which follows acute hydrochlorothiazide administration over-rides any inhibitory effect of the drug on proximal tubular reabsorption, and leads instead to an increase in fractional fluid reabsorption at this site. This effect, combined with the fall in glomerular filtration rate, results in a greatly reduced delivery of fluid to the more distal nephron segments, and is probably largely responsible for the observed antidiuresis.

Medium-term cyclosporin renal dysfunction and its reversibility in rats

1991 ◽  
Vol 260 (6) ◽  
pp. F898-F905
Author(s):  
M. Sabbatini ◽  
L. De Nicola ◽  
F. Uccello ◽  
G. Romano ◽  
G. Papaccio ◽  
...  
Keyword(s):  
Filtration Rate ◽  
Normal Values ◽  
Body Weight Gain ◽  
Female Rats ◽  
Medium Term ◽  
Tubular Cells ◽  
Term Administration ◽  
Single Nephron ◽  
Renal Micropuncture ◽  
Sodium Metabolism

Renal dynamics and morphology were investigated by metabolic, renal micropuncture (RM), and electron microscopy (EM) studies in 50 female rats treated with cyclosporin A (CsA, 40 mg.kg body wt-1.48 h-1) for either 10, 20, or 30 days (groups CsA 10, CsA 20, and CsA 30, respectively); control rats received olive oil (group N). Body weight gain, sodium metabolism, and plasma volume were not altered by CsA administration in any group. GFR was decreased in group CsA 10 vs. group N (-10%, P less than 0.05) and was further impaired in groups CsA 20 and CsA 30 (-45%, P less than 0.01 vs. group N). RM studies showed a significant decrease of single-nephron glomerular filtration rate (SNGFR) in group CsA 30 vs. group N (-26%, P less than 0.01) after the fall of glomerular capillary pressure (Pgc;-8%, P less than 0.05), the increase of afferent arteriole resistance (Ra; +40%, P less than 0.05), and the consequent decrease of glomerular plasma flow (GPF; -28%, P less than 0.05). Thirty days after CsA withdrawal, SNGFR returned to normal values (P less than 0.01 vs. group CsA) as a result of the normalization of Pgc, Ra, and GPF.EM showed only a progressive vacuolation of proximal and distal tubular cells. These data suggest that medium-term administration of CsA is associated with reversible changes in glomerular dynamics and only mild histological lesions.

Cardiac edema in dogs: Proximal tubular and renal function

1979 ◽  
Vol 57 (2) ◽  
pp. 185-192 ◽  
Author(s):  
H. Mandin
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Hydraulic Pressure ◽  
Oncotic Pressure ◽  
Peritubular Capillary ◽  
Filtration Fraction ◽  
Cardiac Edema ◽  
Single Nephron ◽  
Proximal Tubular

In recent dog studies, intrapericardial injection of Freund's adjuvant resulted in sodium retention, pulmonary edema, liver congestion, and ascites. Twenty-two experiments were initiated 6–13 days after pericardial injection. Micropuncture and clearance measurements were made during chronic cardiac tamponade (CCT) and 60 min after pericardiocentesis (PC). Following PC, sodium excretion (UNaV) increased from 12.2 to 41.3 μequiv./min. Glomerular filtration rate (GFR) during CCT was unaltered (from 37.3 to 38.7 mL/min) by PC. Single nephron glomerular filtration rate (sngfr) increased 23% (p < 0.005). Proximal fractional reabsorption (FR) decreased 6% after PC. Kidney filtration fraction (FF) increased from 0.35 to 0.38 (p < 0.01). Superficial nephron FF (six dogs) increased from 0.25 to 0.32 (p < 0.02). Peritubular capillary protein concentrations decreased following PC (from 7.41 to 6.89 g/100 mL), a result of decreasing systemic protein concentrations (from 5.51 to 4.69 g/100 mL). Tubule and capillary hydrostatic pressures (another six dogs) increased 6.2 and 3.3 mmHg, respectively, following PC (p < 0.05 and p < 0.005). The results indicate PC causes increased UNaV. GFR did not appear to influence UNaV. Decreased FR in the proximal tubule is secondary to increased sngfr, absolute absorption (C) remaining unaltered. The behaviour of C is in part explained by diminished capillary oncotic pressure and increased capillary hydraulic pressure.

Effects of parathyroid hormone and calcium and their interrelationship on urinary acidification in the rat

1992 ◽  
Vol 83 (6) ◽  
pp. 711-715 ◽  
Author(s):  
F. Zaladek Gil ◽  
V. L. Costa Silva ◽  
M. F. Cavanal ◽  
G. Malnic
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Parathyroid Hormone ◽  
Filtration Rate ◽  
Calcium Supplementation ◽  
Calcium Ionophore ◽  
Half Time ◽  
Acid Excretion ◽  
Oral Supplementation ◽  
Proximal Tubular

1. The influence of thyroparathyroidectomy on renal function and specifically on acid excretion was studied in rats with or without oral supplementation of calcium. 2. Thyroparathyroidectomy caused a significant decrease in glomerular filtration rate, in the urinary/ plasma inulin ratio and in overall acid excretion. These changes were not corrected by calcium supplementation. 3. Rates of proximal tubular acidification were studied by means of double-barrelled resin/reference microelectrodes. Acidification half-time was significantly increased in both thyroparathyroidectomized and calcium-supplemented thyroparathyroidectomized rats (838 s and 7.40 s, respectively) compared with control rats (5.44 s). 4. When 10−6 mol/l A23187, a calcium ionophore, was added to the luminal bicarbonate solution, the acidification half-time returned to 3.97 s in the thyroparathyroidectomized rats, whereas no significant changes were detected in the properties of acidification in the control rats. 5. These data show that parathyroid hormone and cellular calcium are important factors involved in proximal tubular H+ secretion, which appears to be largely dependent on a well-defined concentration range of these agents.

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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