Renal handling of thyroxine, 3,5,3'- and 3,3',5'-triiodothyronine, 3,3'- and 3',5'-diiodothyronine in man

1987 ◽  
Vol 115 (1) ◽  
pp. 144-148 ◽  
Author(s):  
Jens Faber ◽  
Kaj Siersbæk-Nielsen ◽  
Carsten Kirkegaard
Keyword(s):  
Urinary Excretion ◽  
Creatinine Clearance ◽  
Iodine Atom ◽  
Healthy Subjects ◽  
Tubular Reabsorption ◽  
Transport Mechanisms ◽  
Renal Handling ◽  
Phenolic Ring ◽  
Tubular Transport ◽  
Renal Clearances

Abstract. The 24-h urinary excretion and renal clearance of thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), 3,3'-diiodothyronine (3,3'-T2), and 3',5'-diiodothyronine (3',5'-T2) were measured in 17 healthy subjects. The median urinary excretion was (pmol/24h) T4: 1242, T3: 828, rT3: 12.9, 3,3'-T2: 331, and 3',5'-T2: 5.8. The corresponding renal clearances were in median (ml/min) T4: 31, T3: 133, rT3: 15, 3,3'-T2: 683, and 3',5'-T2: 4.5. The clearances differed mutually (P < 0.01) as well as from the creatinine clearance (P < 0.01) which was in median 87 ml/min. Thus, all iodothyronines studied were subject to tubular transport mechanisms besides glomerular filtration. The 3 iodothyronines with 2 iodine atoms in the phenolic ring of the thyronine molecule, T4, rT3 and 3',5'-T2, were mainly tubularly reabsorbed, whereas those with only one iodine atom in the phenolic ring, T3 and 3,3'-T2, were mainly tubularly secreted. It might be hypothesized that the number of iodine atoms in the phenolic ring determines the direction of the tubular transport (presence of 2 iodine atoms is associated with tubular reabsorption, and of one iodine atom with secretion), whereas the rate of tubular transport decreases with decreasing number of iodine atoms in the tyrosylic ring.

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.

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.

Renal Handling of Beta2-Microglobulin in Patients with Cystic Fibrosis

DICP ◽  
1989 ◽  
Vol 23 (12) ◽  
pp. 1013-1017 ◽  
Author(s):  
Gregory L. Kearns ◽  
Phillip L. Berry ◽  
Joseph A. Bocchini ◽  
Bettina C. Hilman ◽  
John T. Wilson
Keyword(s):  
Cystic Fibrosis ◽  
Creatinine Clearance ◽  
Fractional Excretion ◽  
Tubular Reabsorption ◽  
Hospitalized Patients ◽  
Normal Children ◽  
Renal Handling ◽  
Renal Tubular Reabsorption ◽  
Proximal Tubular ◽  
Renal Tubular

We evaluated the renal handling of beta2-microglobulin (β2-M) and creatinine in healthy outpatients (n = 6), normal children hospitalized for infections treated with antibiotics (not including an aminoglycoside) (n = 4); outpatients with cystic fibrosis (CF; n = 12), and hospitalized patients with CF (n = 6) who received a 10- to 14-day course of antibiotic treatment that included an aminoglycoside. The serum β2-M concentrations in the normal outpatients (2020.1 ± 276.6 μg/L) were significantly lower (p <0.05) than those observed for outpatients (2833.3 ± 202.6 μg/L) or patients with CF (2861.8 ± 340.5 μg/L. There were no significant differences found for creatinine clearance or fractional excretion of β2-M when subjects without CF were compared with those with the disease. Furthermore, no significant differences were observed in hospitalized patients with CF when creatinine clearance and fractional excretion of β2-M were compared between the initiation and conclusion of aminoglycoside treatment. Glomerular filtration and proximal tubular reabsorption of β2-M were not altered in patients with CF. These findings do not support a global defect in proximal renal tubular reabsorption as the underlying cause for altered aminoglycoside clearance in patients with CF.

Tubular transport and urinary excretion of phosphate after renal denervation in the anesthetized rat

1981 ◽  
Vol 240 (6) ◽  
pp. F481-F486 ◽  
Author(s):  
G. Szenasi ◽  
P. Bencsath ◽  
E. Lehoczky ◽  
L. Takacs
Keyword(s):  
Urinary Excretion ◽  
Inorganic Phosphate ◽  
Renal Denervation ◽  
Left Kidney ◽  
Tubular Reabsorption ◽  
Male Rats ◽  
Tubular Transport ◽  
Transport Of Inorganic Phosphate ◽  
Chronic Denervation ◽  
Two Sides

Tubular transport of phosphate (Pi) was studied using clearance and tracer microinjection techniques in Inactin-anesthetized male rats subjected to left kidney denervation. Experiments were conducted in the following groups: i) acute denervation (AD); ii) chronic denervation (CD); iii) acute denervation plus thyroparathyroidectomy (AD + TPTX); iv) microinjection with AD. Besides a marked diuresis and natriuresis with no difference in GFR between innervated (inn) and denervated (den) kidneys, unilateral renal denervation resulted in an increased urinary excretion and decreased tubular reabsorption of inorganic phosphate. Maximum tubular reabsorption of Pi (TmPi) calculated per unit GFR was (means +/- SE): AD, inn: 2.38 +/- 0.04, den: 1.98 +/- 0.06 mumol/ml; CD, inn: 2.66 +/- 0.10, den: 2.19 +/- 0.11 mumol/ml; AD + TPTX, inn: 4.78 +/- 0.06, den: 4.26 +/- 0.08 mumol/ml. Thus, differences in TmPi between the two sides were of the same magnitude in the three groups. Fractional recovery of 32Pi from microinjections in control (C) and postdenervation (D) periods was: early proximal, C: 53.0 +/- 0.81, D: 61.3 +/- 1.07%; late proximal, C: 77.0 +/- 0.81, D: 70.6 +/- 0.60%; early distal, C: 93.7 +/- 0.75, D: 03.5 +/- 0.72%. It is concluded that renal sympathectomy depresses tubular transport of inorganic phosphate in anesthetized rats by a primary action on the proximal convoluted tubule and with a partial compensation in the loop of Henle.

scholarly journals Effect of an acute oral protein load on renal acidification in healthy humans and in patients with chronic renal failure.

1997 ◽  
Vol 8 (5) ◽  
pp. 784-792
Author(s):  
N G de Santo ◽  
G Capasso ◽  
G Malnic ◽  
P Anastasio ◽  
L Spitali ◽  
...  
Keyword(s):  
Renal Failure ◽  
Metabolic Acidosis ◽  
Chronic Renal Failure ◽  
Urinary Excretion ◽  
Healthy Subjects ◽  
Tubular Reabsorption ◽  
Renal Tubules ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance

The effect of a meat load on the renal handling of acid-base balance was studied in ten healthy subjects (GFR by inulin clearance = 98.5 +/- 8.14 ml.min-1.1.73 m-2) and in ten patients affected by chronic renal failure (CRF) (GFR = 39.9 +/- 5.3 ml.min-1.1.73 m-2). After the meat load (2 g.kg-1 body weight of cooked unsalted red meat), GFR increased by 26.9% (peak value) over baseline in healthy subjects and by 32% in CRF patients. The acid-base status of the healthy subjects was in the normal range, whereas the CRF patients disclosed a slight metabolic acidosis. After a meat load, there was, in the healthy subjects, an increase in the filtered load of bicarbonate coupled to an enhanced tubular reabsorption and urinary excretion. The time course between bicarbonate load and urinary excretion was coincident. In CRF patients, the increase of bicarbonate tubular load after the meal was associated with an increase in tubular reabsorption but not in urinary excretion of this anion. The relationship between bicarbonate load and reabsorption was linear in both groups up to the highest filtered loads. Baseline titratable acidity (TA) and ammonium (NH4+) excretion (expressed per ml GFR) were increased in CRF patients as compared with control subjects, but no changes were found after the meat load in both groups in these experimental conditions. The data indicate that the renal tubules contribute to the maintenance of acid-base balance both in healthy subjects and in CRF patients by reabsorbing most of the additional bicarbonate load. The transient, but significant, increase in bicarbonate excretion observed in healthy subjects could be related to the increased tubular load of bicarbonate. In CRF patients, tubular bicarbonate reabsorption was more complete, possibly because of the stimulation of H+ secretion by the mild metabolic acidosis. TA and NH4+ did not participate in tubular compensation of the increased buffer load.

scholarly journals Pilot Studies on Membranes and some Transport Mechanisms in Friedreich's Ataxia

1979 ◽  
Vol 6 (2) ◽  
pp. 285-289 ◽  
Author(s):  
A. Filla ◽  
R. F. Butter Worth ◽  
A. Barbeau
Keyword(s):  
Urinary Excretion ◽  
Screening Program ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
High Density Lipoproteins ◽  
Transport Mechanisms ◽  
Renal Handling ◽  
Pilot Studies ◽  
Preliminary Screening ◽  
Phospho Lipid

SummaryThe observed anomalies in high density lipoproteins in Friedreich's ataxia led us to investigate the state of cellular membranes in this illness. As a preliminary screening program, we studied the shape of erythrocytes; the phospho-lipid content of platelets and the transport properties of these membranes as indirectly reflected in the absorption of Vit E and the renal handling of orally injected taurine. All these investigations were normal, except for a tendency towards more echinocytes in Friedreich's ataxia and the significant increase in taurine urinary excretion after an oral load. We concluded that the possible membrane abnormalities are not major and will have to be searched for with more subtle and specific tests.

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.

Effects of Protein Meals on the Urinary Excretion of Various Plasma Proteins in Healthy Subjects

Nephron ◽  
1999 ◽  
Vol 81 (4) ◽  
pp. 398-405 ◽  
Author(s):  
Takuma Narita ◽  
Hiroji Kitazato ◽  
Jun Koshimura ◽  
Katsunori Suzuki ◽  
Masahiko Murata ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Healthy Subjects ◽  
Plasma Proteins

scholarly journals Glucose-Induced Insulin Hypersecretion in Lipid-Infused Healthy Subjects Is Associated with a Decrease in Plasma Norepinephrine Concentration and Urinary Excretion

2001 ◽  
Vol 86 (10) ◽  
pp. 4901-4907 ◽  
Author(s):  
Christophe Magnan ◽  
Céline Cruciani ◽  
Laurence Clément ◽  
Pierre Adnot ◽  
Mylène Vincent ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Urinary Excretion ◽  
Healthy Subjects ◽  
Plasma Concentrations ◽  
Sympathetic Tone ◽  
Plasma Norepinephrine ◽  
C Peptide ◽  
Lipid Infusion ◽  
Hyperglycemic Clamp ◽  
Glucose Injection

We investigated the effect of a 48 h triglyceride infusion on the subsequent insulin secretion in response to glucose in healthy men. We measured the variations in plasma concentration and urinary excretion of catecholamines as an indirect estimation of sympathetic tone. For 48 h, 20 volunteers received a triglyceride/heparin or a saline solution, separated by a 1-month interval. At time 48 h, insulin secretion in response to glucose was investigated by a single iv glucose injection (0.5 g/kg−1) followed by an hyperglycemic clamp (10 mg·kg−1·min−1, during 50 min). The triglyceride infusion resulted in a 3-fold elevation in plasma free fatty acids and an increase in insulin and C-peptide plasma concentrations (1.5- and 2.5-fold, respectively, P &lt; 0.05), compared with saline. At time 48 h of lipid infusion, plasma norepinephrine (NE) concentration and urinary excretion levels were lowered compared with saline (plasma NE: 0.65 ± 0.08 vs. 0.42 ± 0.06 ng/ml, P &lt; 0.05; urinary excretion: 800 ± 70 vs. 620 ± 25 nmol/24 h, P &lt; 0.05). In response to glucose loading, insulin and C-peptide plasma concentrations were higher in lipid compared with saline infusion (plasma insulin: 600 ± 98 vs. 310 ± 45 pm, P &lt; 0.05; plasma C-peptide 3.5 ± 0.2 vs. 1.7 ± 0.2 nm, P &lt; 0.05). In conclusion, in healthy subjects, a 48-h lipid infusion induces basal hyperinsulinemia and exaggerated insulin secretion in response to glucose which may be partly related to a decrease in sympathetic tone.

Sign in / Sign up

Export Citation Format

Share Document