Postoperative Changes in the concentration of Thyroxine-Binding Prealbumin and Serum Free Thyroxine

Mi, Surks; Jh, Oppenheimer

doi:10.1210/jcem-24-8-794

Cited by 53 publications

(16 citation statements)

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“…Furthermore, the increase in the binding capacity of TBPA induced by adding the purified protein to normal and abnormal sera was equal. Finally, a simple inhibition of T4 binding would not explain the observation by Oppenheimer and co-workers, confirmed in the present studies, that the density of the protein stain is decreased in the prealbumin zone of gel electropherograms of sera from sick patients (8,36).…”

Section: Discussioncontrasting

confidence: 63%

Preparation of I-131-labeled human serum prealbumin and its metabolism in normal and sick patients.

Socolow¹,

Woeber²,

Purdy³

et al. 1965

J. Clin. Invest.

118

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Despite some early doubts concerning its presence in plasma and its physiological function (1-4), the thyroxine-binding prealbumin of human serum (TBPA) is now known to play a significant role in the transport of thyroxine (T4) (5-8). Normally, as assessed by in vitro techniques, TBPA appears to bind at least 25 to 35%o of T4 in serum (5,6). In the serum of many patients with severe acute or chronic illness, however, the proportion of endogenous T4 in serum bound by TBPA and the T4-binding capacity of TBPA decline (8,9). The recent availability of substantial quantities of a highly purified preparation of TBPA has made possible an investigation of the in vivo metabolism of this protein in normal patients and in patients with a variety of disorders that lead to decreased binding of T4 by TBPA in serum. In addition, the cause of this decrease in T4 binding in the serum of such "sick" patients has been evaluated. A portion of the findings has been presented in abstract form (10). While these studies were in progress, Oppenheimer, Surks, Bernstein, and Smith reported similar studies in abstract form (11,12). MethodsHighly purified TBPA was prepared from plasma Fraction IV-6 (method 6) of Cohn and colleagues (13).* Submitted for publication April 9, 1965; accepted June 16, 1965. This The method of purification of the protein and details of its characterization will be described in detail elsewhere (14). Additional characterization of the specific batch of protein employed in the present studies was carried out. Solutions of TBPA (2.0 g per 100 ml), enriched with I'-labeled T4,1 were subjected to electrophoresis in acrylamide gel in a Tris-maleate buffer system,2 pH 9.2. Gel concentrations of 5.0, 7.0, and 8.0 g per 100 ml were employed, and, in some instances, two dimensional gel electrophoretic studies were conducted (15). After electrophoresis, gels were radioautographed and then stained with amido black 10 B.Iodination of TBPA. To minimize the possibility of denaturing the TBPA during the iodination process, a technique was developed for iodinating protein by a microdiffusion process. The technique, an adaptation of that described by Banerjee and Ekins (16), was first employed in tests with human serum albumin (HSA) or with purified TBPA for relatively low specific activity labeling. When the method had been standardized, it was employed for higher specific activity labeling of the TBPA used in the present studies. This was performed as follows. All glassware and buffer media employed were autoclaved before use. A 2.0 g per 100 ml solution of TBPA was prepared in 0.01 M phosphate buffer, pH 7.5, and 200 Al was pipetted into the center well of a single side-armed Warburg flask of 5.0 ml capacity. NaI' (10 to 15 mc, free of carrier iodide and reducing agent),8 together with 60 Ag of unlabeled NaI, was introduced into the main compartment of the vessel in approximately 1 ml of phosphate buffer. Five hundred Al of fresh 3% H202 4 was added to the side arm, and the vessel was closed with a greased ground-glass stopp...

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Section: Discussioncontrasting

confidence: 63%

Preparation of I-131-labeled human serum prealbumin and its metabolism in normal and sick patients.

Socolow¹,

Woeber²,

Purdy³

et al. 1965

J. Clin. Invest.

118

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“…These patients were extremely ill, in some instances moribund, in contrast to the previously reported group without significant elevations, which consisted mainly of ambulatory patients with minor illnesses (1). Diminished total binding capacity of prealbumin (TBPA) in various nonthyroidal illnesses has been reported by Ingbar and associates (34,36,43) and by Oppenheimer and co-workers (30,31). In addition to diminished binding capacity, Oppenheimer and associates showed disappearance of stainable prealbumin-1 on starch gel electrophoresis and a rise in free thyroxine.…”

Section: Methodsmentioning

confidence: 81%

Free thyroxine in human serum: simplified measurement with the aid of magnesium precipitation.

Sterling¹,

Brenner²

1966

J. Clin. Invest.

407

110

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“…Suffice it to say that the liver appeared to participate in the early phase of redistribution of hormone after the acute increase in the level of circulating T4 produced by the loading dose. Although such marked and rapid changes in plasma T, level would not occur in nature, measurable increases in the concentration of free T4 in plasma have been noted in acutely and chronically ill patients (16) and after surgical stress (38). In such situations the liver might serve as a modulator by minimizing the effects on other tissues of increased levels of free T4.…”

Section: Discussionmentioning

confidence: 99%

The kinetics of distribution between plasma and liver of 131-I-labeled L-thyroxine in man: observations of subjects with normal and decreased serum thyroxine-binding globulin.

Cavalieri¹,

Searle²

1966

J. Clin. Invest.

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All but a few studies concerned with the peripheral metabolism of labeled thyroxine 1 in man have ignored the early phase of equilibration of labeled with unlabeled hormone in the tissues (see review in reference 1). Lennon, Engbring, and Engstrom (2) measured the rate of disappearance of radioactivity from the blood during the initial 50 minutes after intravenous injection of T4-131I in humans. They found that the rate of decline in the level of circulating tracer was abnormally slow in patients with hepatic disease and in untreated cases of hypothyroidism and abnormally rapid in thyrotoxic individuals. Haddad (3) analyzed the plasma curve in normal subjects and fit the data to a two compartment kinetics model representing plasma and tissue pools of thyroxine. More recently, Blomstedt and Plantin (4), using only the time curve of plasma disappearance and the rate of excretion of tracer, proposed a four compartment system to describe the distribution and metabolism of labeled T4 in normal humans. Hepatic localization of radioactivity within hours after the intravenous administration of labeled T4 was observed in several studies in man (5-9).The purpose of the present investigation was to study in a quantitative manner the rate of exchange of labeled T4 between plasma and liver in humans with neither thyroid nor hepatic disease. The method involves body sector counting with externally placed detectors and simultaneous meas-

show abstract

Postoperative Changes in the concentration of Thyroxine-Binding Prealbumin and Serum Free Thyroxine

Cited by 53 publications

References 0 publications

Preparation of I-131-labeled human serum prealbumin and its metabolism in normal and sick patients.

Preparation of I-131-labeled human serum prealbumin and its metabolism in normal and sick patients.

Free thyroxine in human serum: simplified measurement with the aid of magnesium precipitation.

The kinetics of distribution between plasma and liver of 131-I-labeled L-thyroxine in man: observations of subjects with normal and decreased serum thyroxine-binding globulin.

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