Thyroxine in unextracted urine

1987 ◽  
Vol 114 (4) ◽  
pp. 503-508 ◽  
Author(s):  
I. Orden ◽  
J. Pie ◽  
M. G. Juste ◽  
J. A. Marsella ◽  
C. Blasco
Keyword(s):  
Urinary Excretion ◽  
Renal Clearance ◽  
Filtration Rate ◽  
Experimental Studies ◽  
Tubular Reabsorption ◽  
Enzyme Hydrolysis ◽  
Renal Handling ◽  
The Mean ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients

Abstract. The aim of this work was to estimate the daily urinary excretion of free and conjugated thyroxine using a direct radioimmunoassay and enzyme hydrolysis. The renal clearance of free T4 was also determined. The mean urinary values of free and total T4 (mean ± 1 sd) in 112 euthyroid controls were 1353 ± 496 and 1855 ± 651 pmol/24 h, respectively. Urinary excretion of free hormone in 13 hyperthyroid patients was 5552 ± 4320 pmol/24 h and total T4 was 8122 ± 7219 pmol/24 h. Urinary free T4 excretion was 223 ± 223 pmol/24 h in hypothyroid patients and total T4 was 542 ± 490 pmol/24 h. These results indicate that daily urinary T4 excretion is a good indicator of thyroid function. The mean renal clearance of free T4 was 52 ± 19 ml/min (mean ± 1 sd) in euthyroid patients, 53.7 ± 12.3 ml/min in hyperthyroid patients, and 67.6 ± 13.1 ml/min in hypothyroid patients. We estimated the endogenous creatinine renal clearance as a control of the renal filtration rate. The data suggest that there is T4 filtration of unbound T4 and partial tubular reabsorption. Further experimental studies will be necessary to clarify the renal handling of thyroxine as well as the fate of reabsorbed T4.

The Influence of Orthophosphate on the Renal Handling of Inorganic Pyrophosphate in Man and Dog

1976 ◽  
Vol 51 (5) ◽  
pp. 435-443 ◽  
Author(s):  
R. G. G. Russell ◽  
Sylvia Bisaz ◽  
H. Fleisch
Keyword(s):  
Urinary Excretion ◽  
Renal Clearance ◽  
Exchange Chromatography ◽  
Urinary Stones ◽  
Isotope Dilution Method ◽  
Dilution Method ◽  
Renal Handling ◽  
Inorganic Pyrophosphate ◽  
The Mean ◽  
Hydrolysis Of

1. The urinary excretion of inorganic pyrophosphate (PP1), a known inhibitor of the growth and aggregation of crystals of calcium phosphate and calcium oxalate, increases after ingestion of orthophosphate (P1). This effect may contribute to the apparent ability of oral phosphate to reduce the formation of urinary stones in man. This paper is a study of the mechanism by which P1 increases PP1 excretion, investigated by renal clearance techniques in man and renal arterial infusion in dogs. PP1 in plasma was measured by an isotope-dilution method after ion-exchange chromatography. 2. The mean renal clearance of endogenous PP1 in ten men was 7·9 ± 1·7 (se) ml/min, and the mean ratio of PP1 clearance to creatinine clearance was 008 ±002 (se). The oral ingestion of P1 increased the urinary excretion and renal clearance of PP1 about threefold, without significantly changing its concentration in plasma. 3. In dogs, the infusion of P1 into one renal artery caused a greater increase in urinary PP1 from the infused than from the non-infused kidney, an effect that could be accentuated by simultaneous intravenous infusion of PP1. In dogs, only 1–3% of an injected or infused dose of PP1 appeared intact in the urine, regardless of whether it was infused into the systemic or renal circulation. 4. These results suggest that P1 has a direct effect on the kidney to increase the excretion of PP1. It is possible that P1 either interferes with tubular reabsorption of PP1, perhaps by competing for a common tubular transport mechanism, or that P1 diminishes the intrarenal hydrolysis of PP1.

THE RENAL HANDLING OF PHOSPHATE IN THYROID DISEASE

1969 ◽  
Vol 45 (2) ◽  
pp. 269-273 ◽  
Author(s):  
B. MALAMOS ◽  
P. SFIKAKIS ◽  
P. PANDOS
Keyword(s):  
Thyroid Disease ◽  
Direct Proof ◽  
Tubular Reabsorption ◽  
Serum Phosphate ◽  
Serum Phosphate Level ◽  
Fasting Serum ◽  
Renal Handling ◽  
The Mean ◽  
Serum Inorganic Phosphate ◽  
Hypothyroid Patients

SUMMARY The fasting serum phosphate level, the tubular maximal (Tm) phosphate reabsorption and the mean renal phosphate threshold were measured in 18 hyper- and six hypothyroid patients in comparison with 11 euthyroid control subjects. A significant increase of serum inorganic phosphate, phosphate Tm and of the mean renal phosphate threshold were found in hyperthyroidism. These findings suggest an increased tubular reabsorption of phosphate in hyperthyroidism. Four main possible mechanisms of such a renal handling of phosphate in thyroid disease are briefly mentioned although their acceptance needs more direct proof.

Renal filtration and excretion of aluminium in the rat: dose-response relationships and effects of aluminium speciation

1995 ◽  
Vol 14 (6) ◽  
pp. 494-499 ◽  
Author(s):  
CJ Lote ◽  
JA Wood ◽  
A. Thewles ◽  
M. Freeman
Keyword(s):  
Filtration Rate ◽  
Rat Plasma ◽  
Tubular Reabsorption ◽  
The Body ◽  
Aluminium Sulphate ◽  
Renal Handling ◽  
Aluminium Speciation ◽  
Aluminium Citrate ◽  
Aluminium Species ◽  
Filtered Load

The known toxicity of aluminium, and the toxicity of agents (such as desferrioxamine) used to remove alumini um from the body, has prompted us to investigate whether there may be ways of enhancing aluminium excretion by exploiting the normal renal handling of aluminium. Aluminium (as sulphate or citrate) was administered intravenously to conscious rats at doses ranging from 25 μg (0.93 μmol) to 800 μg (29.6 μmol) aluminium, and alu minium excretion was monitored over the following 2 h. Measurements of the filterability of aluminium from the rat plasma, and the glomerular filtration rate (inulin clearance), enabled us to calculate the filtered load of alu minium, and hence determine aluminium reabsorption. At all doses of administered aluminium, that adminis tered as sulphate was excreted less effectively than that administered as citrate. This difference was attributable to the much greater filterability of aluminium administered as citrate. However, for any given filtered load, the excre tion of aluminium administered as citrate was not signifi cantly different (in either fractional or absolute terms) from the excretion of aluminium administered as sulphate. It seems likely that, following aluminium sulphate administration, the filtered aluminium may be an alumini um citrate form which is then reabsorbed in the same way as aluminium administered as citrate. It is thus apparent that aluminium removal from the body could be further enhanced if it were possible to pre vent the tubular reabsorption of the aluminium species which is so effectively filtered following aluminium citrate administration.

Serial Studies of the Renal Clearance of Urate and Inulin during Pregnancy and after the Puerperium in Normal Women

1974 ◽  
Vol 47 (6) ◽  
pp. 559-565 ◽  
Author(s):  
P. F. Semple ◽  
W. Carswell ◽  
J. A. Boyle
Keyword(s):  
Urinary Excretion ◽  
Renal Clearance ◽  
Post Partum ◽  
Late Pregnancy ◽  
Serum Urate ◽  
Control Value ◽  
The Mean ◽  
Normal Women ◽  
In Pregnancy ◽  
Made In

1. A serial study of renal clearance of urate and inulin was made in thirteen normal women in early, mid and late pregnancy and 6–15 weeks after delivery. 2. The mean serum urate concentration was low in early and mid pregnancy but rose in late pregnancy towards the control value. 3. Clearances of urate and inulin were consistently elevated throughout pregnancy to about 150% of the post-partum values. The ratio of clearance of urate to clearance of inulin was the same in pregnancy as it was after the puerperium. 4. The urinary excretion of urate was increased only in late pregnancy.

TRIIODOTHYRONINE AND THYROXINE NUCLEAR RECEPTORS IN LYMPHOCYTES FROM NORMAL, HYPER- AND HYPOTHYROID SUBJECTS

1977 ◽  
Vol 85 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Th. Lemarchand-Béraud ◽  
A.-Ch. Holm ◽  
B. R. Scazziga
Keyword(s):  
Nuclear Receptors ◽  
Binding Sites ◽  
Intact Cell ◽  
Affinity Constant ◽  
Limited Capacity ◽  
Intact Cells ◽  
High Affinity ◽  
The Mean ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients

ABSTRACT In an investigation of thyroxine (T4) and triiodothyronine (T3) receptors in humans, the lymphocyte was chosen as the target cell. This study was performed to elucidate whether T3 and T4 bind to different receptors, if T4 is bound only after conversion into T3, and whether there is any modification of the receptors in hyper- and hypothyroidism. Lymphocytes were found to possess a high-affinity, limited-capacity binding sites for both T4 and T3. The mean equilibrium affinity constant (Ka) was 2.28 · 1010 ± 0.21 m−1 for T3, and 0.98 · 1010 ± 0.16 m−1 for T4. The mean number of saturable binding sites was 115 for T3, and 102 for T4. The binding capacities and affinities also determined in the lymphocyte nuclei isolated after incubation of the intact cell, were similar to those observed in the intact cells. In competition experiments, labelled T4 was as readily displaced by T3 as by T4 itself, whereas labelled T3 was displaced only by a 40 times higher concentration of T4 than T3. These observations suggest identical receptors for the two hormones and a binding of T4 as such, provided it is not in competition with T3. In lymphocytes from hyperthyroid patients, receptor affinities and numbers remained unchanged. In lymphocytes from hypothyroid patients, the affinity was normal, but the mean number of T3 binding sites was increased to 310 (P < 0.001), to return to normal after a few months of treatment.

THE "EFFECTIVE THYROXINE RATIO" – NEW IN VITRO TEST OF THYROID FUNCTION AND ITS CORRELATION WITH FREE THYROXINE

1974 ◽  
Vol 76 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Janusz Nauman ◽  
Alicja Nauman
Keyword(s):  
Pregnant Women ◽  
Normal Subjects ◽  
Free Thyroxine ◽  
In Vitro Test ◽  
High Reproducibility ◽  
Vitro Test ◽  
The Mean ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients

ABSTRACT The effective thyroxine ratio (ETR) and absolute concentration of free thyroxine (AFT4) were estimated in the sera of 31 normal subjects, 27 hyperthyroid patients, 12 hypothyroid patients and 21 euthyroid pregnant women. The mean ETR value in the controls was 1.0 ± 0.18, in the hyperthyroid patients 1.31 ± 0.25, in the hypothyroid patients 0.71 ± 0.21 and in normal pregnant women 0.99 ± 0.24. The mean AFT4 in the normal subjects was 3.0 ± 0.53 ng/100 ml, in the hyperthyroid patients 9.49 ± 2.44 ng/ 100 ml, in the hypothyroid patients 0.58 ± 0.15 ng/100 ml and in the pregnant women 2.84 ± 0.63 ng/100 ml, respectively. High reproducibility of ETR and a significant positive correlation between ETR and AFT4 with r = 0.96 suggest that ETR might be a suitable in vitro test for routine clinical evaluation of the thyrometabolic state.

The Relation between the Urinary Excretion of Inorganic Phosphate and Sodium

1971 ◽  
Vol 41 (3) ◽  
pp. 249-256 ◽  
Author(s):  
M. Fulop ◽  
P. Brazeau
Keyword(s):  
Glomerular Filtration Rate ◽  
Sodium Chloride ◽  
Urinary Excretion ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Inorganic Phosphate ◽  
Filtration Rate ◽  
Tubular Reabsorption ◽  
Back Pressure

1. The relation between the urinary excretion of inorganic phosphate and sodium was studied in anaesthetized dogs subjected to acute unilateral increases of ureteral back-pressure while receiving infusions of iso-osmotic sodium chloride. Under these circumstances modest increases of ureteral back-pressure, +14 to +23 cmH2O, were associated with relatively small changes of glomerular filtration rate from control values (−12.7 to +8.2%). 2. Increased ureteral back-pressure caused closely proportionate decreases of urinary phosphate and sodium excretion regardless of whether glomerular filtration rate increased, decreased or remained unchanged. When glomerular filtration rate increased or remained stable, the decreases of phosphate and sodium excretion were attributable to closely proportionate increases of tubular reabsorption of sodium and of phosphate. The increased tubular reabsorption of phosphate may be causally related to the increased tubular reabsorption of sodium.

Experimental Studies Comparing Iohexol and 51Cr-Edta for Glomerular Filtration Rate Measurements

1995 ◽  
Vol 36 (1) ◽  
pp. 58-63 ◽  
Author(s):  
S. Lundqvist ◽  
S.-O. Hietala ◽  
K. Karp
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Clearance ◽  
Filtration Rate ◽  
Plasma Clearance ◽  
Experimental Studies ◽  
Total Plasma ◽  
Total Plasma Clearance ◽  
51Cr Edta

The total plasma clearance as well as the renal clearance of iohexol were evaluated for determination of the glomerular filtration rate (GFR) in 16 anesthetized pigs. The iohexol levels in urine and plasma were measured by X-ray fluorescence. The total plasma clearance of 1 and 4 ml/kg b.w. of iohexol 300 mg I/ml was compared to the simultaneously as well as nonsimultaneously calculated total plasma clearance of 51Cr-EDTA. The total plasma clearance of 51Cr-EDTA and of iohexol turned out to be equal and independent of the injected dose of iohexol. The injected dose did not have any effect on the renal clearance of iohexol either. It is concluded that iohexol and 51Cr-EDTA are similar as marker substances for determination of the GFR.

Functional and morphologic patterns of renal maturation in the developing guinea pig

1981 ◽  
Vol 241 (6) ◽  
pp. F618-F624 ◽  
Author(s):  
C. Merlet-Benichou ◽  
M. Pegorier ◽  
M. Muffat-Joly ◽  
C. Augeron
Keyword(s):  
Filtration Rate ◽  
Tubular Reabsorption ◽  
Proximal Tubules ◽  
Sodium Reabsorption ◽  
Morphologic Change ◽  
Concomitant Increase ◽  
Renal Handling ◽  
Salt Loading ◽  
Glomerular Volume ◽  
Proximal Tubular

Clearance experiments were carried out in fetal, young, and adult pigs undergoing salt loading. Kidney sections were histologically examined and the proximal tubular length, glomerular volume, and number of glomeruli were estimated. Between days 48 and 55 of gestation, the significant increase in glomerular filtration rate was proportionately higher than the concentration increase in water, total solutes, and sodium reabsorption. During this period, neither the proximal tubular length nor the glomerular volume of the juxtamedullary nephrons changed significantly. The main morphologic change took place in the superficial cortex, where new glomeruli attached to very short tubules differentiated. From day 55 to birth, the increase in water, total solutes, and sodium filtered loads was proportionately smaller than the concomitant increase in tubular reabsorption. During this phase, the major morphologic change was the significant lengthening of the proximal tubules of the juxtamedullary and superficial nephrons. These findings suggest that for water, sodium, and total solutes the maturation of superficial nephrons is accompanied by a phase of functional glomerular preponderance. Despite the differentiation of the superficial nephrons, renal handling of normally filtered glucose did not change significantly. Functional glomerulotubular coupling for water, sodium, and total solutes took place soon after birth.

Renal handling of 3,3',5'-triiodothyronine (reverse T3) compared to thyroxine and 3,5,3'-triiodothyronine in different thyroid function states in man

1980 ◽  
Vol 94 (3) ◽  
pp. 337-340 ◽  
Author(s):  
Preben Rogowski ◽  
Jens Faber ◽  
Kaj Siersbæk-Nielsen
Keyword(s):  
Glomerular Filtration ◽  
Renal Clearance ◽  
Serum Concentrations ◽  
Transport Mechanisms ◽  
Reverse T3 ◽  
Renal Handling ◽  
Phenolic Ring ◽  
Tubular Transport ◽  
Hormone Excretion ◽  
Hyperthyroid Patients

Abstract. The aim of the present work was to investigate the renal clearance of 3,3',5'-triiodothyronine (reverse T3, rT3) compared to thyroxine (T4) and 3,5,3'-triiodothyronine (T3) clearance. The urinary excretion of T4. T3 and rT3 was estimated by radioimmunoassay, serum unbound hormones (AFT4, AFT3, AFrT3) were measured using ultrafiltration technique. In 27 euthyroid controls the 24 h urinary T4 excretion was in median 1.7 nmol. T3 excretion 0.8 nmol and rT3 excretion 0.08 nmol. Serum AFT4 was in median 59 pmol/l, AFT3 7.9 pmol/l and AFrT3 2.2 pmol/l. Creatinine clearance was in median 93 ml/min. Median renal clearance of T4, T3 and rT3 were 26, 70 and 25 ml/min, and apparent tubular re-absorption was in average 77, 27 and 77%, respectively. In 18 hyperthyroid patients urinary hormone excretion was highly increased and was found parallel to the increase in serum concentrations of free hormones. Clearance and per cent tubular re-absorption of T4 and rT3 were equal to and not different from control values, but T3 clearance seemed to be increased to values higher than glomerular filtration rate (GFR). In 8 patients with hypothyroidism low urinary hormone excretion was found. Clearance of T4 and rT3 did not differ from control values, but T3 clearance was reduced. Our data show that T4, T3 and rT3 are excreted by glomerular filtration of free hormones and suggest that tubular transport mechanisms are involved. The hypothesis is put forward that the renal handling of the thyronines is influenced by the number of the outer phenolic ring iodine atoms.

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