thyronines and Liver-Cirrhosis--Alcoholic

A simple and accurate method for estimation of the free fractions (FFT) of T4, T3, rT3, 3,3'-diiodothyronine (3,3'-T2) and 3',5'-diiodothyronine (3',5'-T2) in serum is presented. The method is based on ultrafiltration of serum pre-incubated with tracers of high specific activity, followed by purification of the ultrafiltrate on small Sephadex columns. The addition of tracer only dilutes serum negligible (about 5%) and the ultrafiltration procedure only removes about 7% of the volume of serum, thus probably not disturbing the equilibrium between the free and protein bound fraction of iodothyronine. Progressive reduction of tracer to less than 10% of the amount usually used did not reduce the FFT of any of the iodothyronines. In contrast, addition of T4 to serum led to an increase of all FFTs except that of 3',5'-T2. These data suggest that FFT of T4, T3, rT3 and 3,3'-T2 primarily is determined by the amount of T4 present in serum and that significant amounts of these iodothyronines are bound to TBG, whereas 3',5'-T2 possibly primarily is bound to albumin. The median FFT of T4, T3, rT3, 3,3'-T2 and 3',5'-T2 in serum from euthyroid subjects (n = 38) was: 0.030, 0.29, 0.14, 1.10 and 1.07%, respectively. The corresponding median free concentrations in pmol/l were: 30, 4.79, 0.59, 0.44 and 0.77, respectively. Pregnant women in 3rd trimester had normal levels of free T4, free T3 and free rT3, whereas the median free 3,3'-T2 was reduced in contrast to elevated median free 3',5'-T2.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Diiodothyronines; Female; Humans; Hyperthyroidism; Kidney Failure, Chronic; Liver Cirrhosis, Alcoholic; Male; Middle Aged; Pregnancy; Thyronines; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Ultrafiltration

Simultaneous kinetic studies of 3,5-diiodothyronine (3,5-T2) and T3 were performed in 8 patients with biopsy proven cirrhosis and in 15 healthy subjects using the single injection, noncompartmental approach. The following T3 kinetic data were obtained in patients with cirrhosis and normal subjects (mean +/- SD): serum T3 (nmol/liter) 1.27 +/- 0.30 vs. 1.79 +/- 0.28 (P less than 0.001); MCR [liters X day-1 X (70 kg)-1] 22.9 +/- 5.3 vs. 26.7 +/- 4.4 (P less than 0.10); production rate [nmol X day-1 X (70 kg)-1] 29.0 +/- 9.6 vs. 47.7 +/- 9.0 (P less than 0.001). In patients with cirrhosis serum 3,5-T2 levels were reduced to 58 +/- 38% of those found in normal subjects (P less than 0.02). The MCR was unaffected, 125 +/- 85%, whereas the production rate was reduced to 57 +/- 26% (P less than 0.005). The conversion rate from T3 to 3,5-T2 was unaltered, 96 +/- 34% of that found in normals. It is concluded that reduced serum levels of 3,5-T2 in cirrhosis are due to a diminished amount of substrate, T3, and not to decreased 3'-deiodination of T3 or to an increase clearance of 3,5-T2.

Topics: Adult; Diiodothyronines; Female; Humans; Kinetics; Liver Cirrhosis, Alcoholic; Male; Metabolic Clearance Rate; Middle Aged; Sex Factors; Thyronines; Triiodothyronine

A radioimmunoassay (RIA) for serum 3,5-diiodothyronine (3,5-T2) was developed using small Sephadex G 25 (fine) columns. Prior to the RIA an alcohol extraction of 3,5-T2 from serum and an evaporation of the extract was performed. The recovery of 3,5-T2 added to serum was in mean (plus or minus SEM) 101 plus or minus 11%. The lower detection limit was 0.012 pmol/column corresponding to 14 pmol/l using 3 ml serum. Due to a 5% cross-reaction of 3,5-T2 antibody with 3,5,3'-triiodothyronine (T3) individual correction for T3 present in serum was necessary. Serum 3,5-T2 levels in 52 éuthyroid controls were (mean plus or minus SD) 105 plus or minus 51 pmol/l. Serum levels were higher in men (125 plus or minus 56 pmol/l. Serum levels were higher in men (125 plus or minus 56 pmol/l) than in women (84 plus or minus 34 pmol/l, P less than 0.005). In 17 hyperthyroid subjects serum 3,5-T2 levels were elevated (232 plus or minus 187 pmol/l, P less than 0.005). In hypothyroid patients and patients with non-toxic goitre serum 3,5-T2 levels did not differ significantly from control values, whereas 8 patients with liver cirrhosis had severely reduced serum 3,5-T2 concentrations (20 plus or minus 23 pmol/l, P less than 0.001).

Topics: Adolescent; Adult; Age Factors; Aged; Diiodothyronines; Female; Humans; Liver Cirrhosis, Alcoholic; Male; Middle Aged; Propranolol; Radioimmunoassay; Sex Factors; Thyroid Diseases; Thyronines

Turnover studies of T4, T3, rT3, 3',5'-diiodothyronine (3',5'-T2), 3,3'-diiodothyronine (3,3'-T2), and 3'-monoiodothyronine (3'-T1) were performed in 10 patients with alcoholic cirrhosis of the liver and 9 euthyroid, healthy controls using the single injection, noncompartmental approach. The kinetics of all 6 iodothyronines were studied in the same individuals. A newly developed, simple and reproducible gel separation technique, followed by antibody extraction, was used for the quantitation of tracer in serum. Serum T4, T3, and 3,3'-T2 levels were reduced in patients with liver cirrhosis, whereas serum rT3 and 3',5'-T2 levels were increased, Serum 3'-T1 levels were unaltered. A general tendency toward reduced MCRs was observed. The following median MCRs (liters per day per 70 kg BW) were found (cirrhotics vs. controls): T4, 1.13 vs. 1.19 (P = NS); T3, 16 vs. 20 (P less than 0.05); rT3, 81 vs. 147 (P less than 0.01); 3',5'-T2, 131 vs. 279 (P less than 0.01); 3,3'-T2, 533 vs. 1116 (P less than 0.01); and 3'-T1, 375 vs. 539 (P less than 0.05). The production rates (nanomoles per day per 70 kg BW) of T4, rT3, and 3,'5'-T2 were not significantly altered in patients with cirrhosis (cirrhotics vs. controls): 100 vs. 117, 47.5 vs. 52.0, and 14.5 vs. 13.9, respectively. In contrast, the following pronounced reductions in production rates of T3, 3,3'-T2, and 3'-T1 were found: 19.1 vs. 38.8 (P less than 0.01), 13.2 vs. 36.8 (P less than 0.01), and 15.7 vs. 28.6 (P less than 0.05), respectively. Assuming that thyroidal secretion contributes little rT3 and 3',5'-T2, the conversion rates from T4 to rT3 and further to 3',5'-T2 were calculated and found to be unaffected in patients with liver cirrhosis (48% vs. 34% in controls and 34% vs. 26% in controls, respectively). No tendency toward major changes in the activity of the nondeiodinative metabolic pathways was observed. In conclusion, our data show that liver cirrhosis profoundly changes the kinetics of all iodothyronines studied. Further, the 5-deiodination of T4 and rT3 is unaffected in patients with liver cirrhosis. In contrast, a general inhibition of the 5'-deiodinations seems to exist in patients with liver cirrhosis. Thus, our data are compatible with the existence of a common 5-deiodinase and a common 5'-deiodinase for the sequential deiodination of the iodothyronines in man.

Topics: Adult; Aged; Diiodothyronines; Female; Humans; Kinetics; Liver Cirrhosis, Alcoholic; Male; Metabolic Clearance Rate; Middle Aged; Thyroid Hormones; Thyronines; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

A simple, reproducible, and highly specific RIA has been developed for measurement of 3',5'-diiodothyronine ((3',5'-T2) in unextracted serum. Interference in binding of radioactive 3',5'-T2 to anti-3',5'-T2 by serum proteins was minimized by using 0.4 M phosphate buffer (pH 6.2) and merthiolate. The detection threshold of the RIA was 2.5 ng/100 ml. Recovery of nonradioactive 3',5'-T2 added to serum averaged 99%. T4, T3, and rT3 cross-reacted with 3',5'-T2-binding sites on anti-3',5'-T2 antibody only to the extent of 0.0025, less than 0.0004, and 0.22%, respectively. 3'-Monoiodothyronine cross-reacted 1.7%. Serum 3',5'-T2 concentrations were (mean +/- SD) 6.4 +/- 2.4 ng/100 ml in 53 normal subjects, 4.2 +/- 3.5 ng/100 ml in 7 hypothyroid patients, 14.9 +/- 7.7 ng/ml in 25 patients with hepatic cirrhosis, and 14.3 +/- 5.3 ng/100 ml in 31 newborns' cord blood sera. The values in each of the latter four groups were significantly different from normal. The mean serum 3',5'-T2 concentration of 7.7 +/- 2.5 ng/ml in eight subjects in the third trimester of pregnancy did not differ significantly from normal at a time when serum T4 and T3 were clearly elevated. Oral administration of 300 microgram rT3 to 9 normal subjects led to a mean maximal increase in serum 3',5'-T2 concentration of 45% at 1 h. Total fasting in 3 obese subjects was associated with a significant increase in serum 3',5'-T2 from 8.6 to 16.3 ng/100 ml at 6-8 days; serum rT3 increased similarly, while serum T3 decreased and T4 did not change. Administration of dexamethasone (2 mg also associated with nearly parallel increases in serum 3',5'-T2 and rT3 and a decrease in serum T3. 3',5'-T2 concentrations were also measured in amniotic fluids at different stages of gestation; the mean value of 15.2 ng/100 ml at 15-20 weeks gestation was significantly higher than that of 5.8 ng/ml at 33-40 weeks gestation. Pronase hydrolysates of 9 autopsy specimens of normal thyroid glands contained (mean +/- SD) 350 +/- 144 microgram T4 and 0.24 +/- 0.15 microgram 3',5'-T2/g wet wt. On the basis of these data and those available for MCRs of 3',5'-T2 and T4, it was estimated that thyroidal secretion contributes less than 1% of 3',5'-T2 measured in serum of normal man. The various data suggest that: 1) 3',5'-T2 is a normal component of human serum; 2) almost all 3',5'-T2 in human serum derives from extrathyroidal sources; and 3) changes in serum 3',5'-2 generally parallel those in rT3.

Topics: Adolescent; Adult; Aged; Amniotic Fluid; Antibodies; Antibody Specificity; Diiodothyronines; Fasting; Female; Fetal Blood; Graves Disease; Humans; Hyperthyroidism; Hypothyroidism; Liver Cirrhosis, Alcoholic; Male; Middle Aged; Pregnancy; Radioimmunoassay; Thyroid Gland; Thyroid Hormones; Thyronines