THE INFLUENCE OF THE THYROID GLAND ON THE CATABOLISM OF 131I-LABELLED HOMOLOGOUS γ-GLOBULIN IN THE GUINEA-PIG

1960 ◽  
Vol 21 (1) ◽  
pp. 91-96 ◽  
Author(s):  
C. P. FARTHING ◽  
JULIA GERWING ◽  
JENNIFER SHEWELL
Keyword(s):  
Thyroid Gland ◽  
Guinea Pig ◽  
Half Life ◽  
Guinea Pigs ◽  
Serum Globulin ◽  
Thyroxine Treatment ◽  
Biological Half Life ◽  
Catabolic Rate ◽  
Thyroid Glands

SUMMARY 1. Removal of the thyroid glands from guinea-pigs had no significant effect on the biological half-life of injected homologous 131I-labelled γ-globulin, or on the catabolic rate of the same material expressed as percentage intravascular protein broken down per day. 2. Administration of thyroxine to guinea-pigs decreased the biological half-life of injected 131I-labelled γ-globulin from 8·3 days in control animals to 5·6 days: the catabolic rate was correspondingly increased from 17·4±1·3% to 22·1 ± 3·4% intravascular protein per day. 3. Prolonged thyroxine treatment tended to increase serum globulin levels, particularly the γ-globulin. It is suggested that there must be a greatly increased synthesis of γ-globulin accompanying the increased catabolism of this material in hyperthyroid guinea-pigs.

THE CATABOLISM OF 131I-LABELLED HOMOLOGOUS γ-GLOBULIN IN NORMAL, HYPERTHYROID AND HYPOTHYROID RATS

1960 ◽  
Vol 21 (1) ◽  
pp. 83-89 ◽  
Author(s):  
C. P. FARTHING ◽  
JULIA GERWING ◽  
JENNIFER SHEWELL
Keyword(s):  
Serum Protein ◽  
Half Life ◽  
Total Serum Protein ◽  
Total Serum ◽  
Protein Levels ◽  
Globulin Level ◽  
Thyroxine Treatment ◽  
Biological Half Life ◽  
Catabolic Rate

SUMMARY The biological half-life of injected homologous 131I-γ-globulin was found to be 4·8 days in euthyroid, 5·8 days in thyroidectomized, and 3·8 days in thyroxine-treated rats. The catabolic rate of homologous γ-globulin, expressed as a percentage of the intravascular protein broken down per day, was decreased from 25·5% in normal rats to 22·5% in thyroidectomized animals, and increased to 39·2% by thyroxine treatment. Total serum protein levels were not affected by thyroxine treatment (0·02 mg/kg) in the rat, but increased after thyroidectomy. This increase was chiefly due to an increased γ-globulin level, and it is postulated that catabolism of γ-globulin in the thyroidectomized rat is decreased to a greater extent than is γ-globulin synthesis.

WATER AND ELECTROLYTE DISTRIBUTION IN RAT AND GUINEA-PIG THYROID GLANDS

1971 ◽  
Vol 50 (4) ◽  
pp. 561-576 ◽  
Author(s):  
S. Y. CHOW ◽  
D. M. WOODBURY
Keyword(s):  
Thyroid Gland ◽  
Guinea Pig ◽  
Interstitial Fluid ◽  
Equilibrium Potential ◽  
Excellent Correlation ◽  
Nernst Equation ◽  
Thyroid Glands ◽  
Uptake Studies ◽  
Rat Thyroid ◽  
Cellular Compartments

SUMMARY Procedures for the calculation of the volume of water and the Na+, K+ and Cl− concentrations in the three anatomical compartments of the thyroid (interstitium, follicular cells and lumen) are described. There was an excellent correlation between the volume of water of these three compartments calculated from the total water, [14C]inulin space and histometric measurements of the thyroid gland and the results obtained from 3H2O-uptake studies. Na+ and K+ concentrations in the luminal fluid of rat and guinea-pig thyroid glands were the same as those in the interstitial fluid which is an ultrafiltrate of plasma. Cl− concentration in the luminal fluid of thyroid gland was usually lower than that in the interstitial fluid. The concentration depends on the amount of colloid present in the follicular lumen. In the cellular fluid of the thyroid follicle, Na+ and Cl− concentrations were low and K+ concentration was high. The Cl− equilibrium potential between the interstitial and the cellular compartments, calculated from the corresponding Cl− concentrations by the Nernst equation, was the same as for previous values reported for the intracellular potentials determined by micro-electrode techniques in both rat and guinea-pig thyroid glands. In the rat thyroid, the calculated Cl− equilibrium potential between the interstitial and the luminal compartments was the same as the measured intra-luminal potential. However, in the guinea-pig thyroid the calculated Cl− equilibrium potential between the interstitial and the luminal fluids was considerably higher than the measured intra-luminal potential.

EFFECTS OF DIETARY IODINE ON THE UTILIZATION OF RADIOACTIVE IODIDE BY THE RAT

1963 ◽  
Vol 41 (7) ◽  
pp. 1547-1555 ◽  
Author(s):  
G. A. Robinson
Keyword(s):  
Thyroid Gland ◽  
Half Life ◽  
Sprague Dawley ◽  
High Iodine ◽  
In Vivo Measurements ◽  
Biological Half Life ◽  
Sprague Dawley Rats ◽  
Lower Protein ◽  
Life Values

Sprague–Dawley rats were fed on diets ranging from 40 μg I/kg to 3885 μg I/kg. Single doses of iodide-131 were injected intraperitoneally into each of the rats. In vivo measurements of radioisotope levels were made at intervals for 11 to 15 days over the neck and thorax. Thyroidal I131 curves were obtained by using a fraction of the thoracic counts to correct for the extrathyroidal component of the neck counts. Animals on low-iodine diets concentrated I131 in their thyroids more rapidly and to greater peak values, had lower protein-bound iodine (I127) concentrations, and lower total thyroidal iodide (I127) content than did rats in the high-iodine groups. An attempt was made to compensate the thyroidal counts for the continuing decrease in the concentration of iodide-131 in the plasma. From this attempt was derived the "thyroidal index", a parameter which may be related to the rate of exchange of the total thyroidal iodine stores. Biological half-life values (I131 in thyroid gland) for the low-iodine groups were larger than those for the high-iodine animals. The hypothesis is advanced that, at least for the conditions reported here, the biological half-life does not adequately reflect thyroidal activity; exchange of iodine between the rat and its environment is considered to be the more important factor in controlling the numerical value of this parameter.

EFFECTS OF DIETARY IODINE ON THE UTILIZATION OF RADIOACTIVE IODIDE BY THE RAT

1963 ◽  
Vol 41 (1) ◽  
pp. 1547-1555 ◽  
Author(s):  
G. A. Robinson
Keyword(s):  
Thyroid Gland ◽  
Half Life ◽  
Sprague Dawley ◽  
High Iodine ◽  
In Vivo Measurements ◽  
Biological Half Life ◽  
Sprague Dawley Rats ◽  
Lower Protein ◽  
Life Values

Sprague–Dawley rats were fed on diets ranging from 40 μg I/kg to 3885 μg I/kg. Single doses of iodide-131 were injected intraperitoneally into each of the rats. In vivo measurements of radioisotope levels were made at intervals for 11 to 15 days over the neck and thorax. Thyroidal I131 curves were obtained by using a fraction of the thoracic counts to correct for the extrathyroidal component of the neck counts. Animals on low-iodine diets concentrated I131 in their thyroids more rapidly and to greater peak values, had lower protein-bound iodine (I127) concentrations, and lower total thyroidal iodide (I127) content than did rats in the high-iodine groups. An attempt was made to compensate the thyroidal counts for the continuing decrease in the concentration of iodide-131 in the plasma. From this attempt was derived the "thyroidal index", a parameter which may be related to the rate of exchange of the total thyroidal iodine stores. Biological half-life values (I131 in thyroid gland) for the low-iodine groups were larger than those for the high-iodine animals. The hypothesis is advanced that, at least for the conditions reported here, the biological half-life does not adequately reflect thyroidal activity; exchange of iodine between the rat and its environment is considered to be the more important factor in controlling the numerical value of this parameter.

SUCCINIC DEHYDROGENASE ACTIVITY OF THE THYROID GLAND AS AN INDICATOR OF THE ACTIVITY OF THE THYROID CELLS

1960 ◽  
Vol XXXV (I) ◽  
pp. 135-138 ◽  
Author(s):  
Antti Telkkä ◽  
K. J. Heikkilä ◽  
Väinö K. Hopsu
Keyword(s):  
Thyroid Gland ◽  
Enzymatic Activity ◽  
Dehydrogenase Activity ◽  
Guinea Pigs ◽  
Quantitative Estimation ◽  
Succinic Dehydrogenase ◽  
Succinic Dehydrogenase Activity ◽  
Thyroid Cells ◽  
Thyroid Glands ◽  
Sensitive Method

ABSTRACT The thyroid glands of guinea-pigs were stimulated by the administration of methylthiouracil. The histochemically demonstrable succinic dehydrogenase activity was determined by the quantitative tetrazolium method. A marked increase in the enzymatic activity of the stimulated thyroid glands was observed and measured. The quantitative estimation of enzymatic activity is apparently a reliable and sensitive method for demonstrating the activity of the thyroid cells.

scholarly journals In Vitro Activity of Gemifloxacin (SB-265805, LB20304a) against Legionella pneumophila and Its Pharmacokinetics in Guinea Pigs with L. pneumophila Pneumonia

2001 ◽  
Vol 45 (8) ◽  
pp. 2204-2209 ◽  
Author(s):  
Paul H. Edelstein ◽  
Takashi Shinzato ◽  
Edward Doyle ◽  
Martha A. C. Edelstein
Keyword(s):  
Guinea Pig ◽  
Legionella Pneumophila ◽  
Half Life ◽  
Guinea Pigs ◽  
Clinical Effectiveness ◽  
Drug Dose ◽  
Time Curve ◽  
Once Daily ◽  
Legionnaires Disease

ABSTRACT The activity of gemifloxacin against intracellularLegionella pneumophila and for the treatment of guinea pigs with L. pneumophila pneumonia was studied. Gemifloxacin, azithromycin, and levofloxacin (1 μg/ml) reduced bacterial counts of two L. pneumophila strains grown in guinea pig alveolar macrophages by 2 to 3 log10 units. Gemifloxacin and levofloxacin had roughly equivalent intracellular activities. In contrast, erythromycin had static activity only. Therapy studies of gemifloxacin, azithromycin, and levofloxacin were performed in guinea pigs with L. pneumophila pneumonia. When gemifloxacin (10 mg/kg) was given by the intraperitoneal (i.p.) route to infected guinea pigs, mean peak levels in plasma were 1.3 μg/ml at 0.5 h and 1.2 μg/ml at 1 h postinjection. The terminal half-life phase of elimination from plasma was 1.3 h, and the area under the concentration-time curve from 0 to 24 h (AUC0–24) was 2.1 μg · h/ml. For the same drug dose, mean levels in lungs were 3.4 μg/g at both 0.5 and 1 h, with a half-life of 1.5 h and an AUC0–24 of 6.0 μg · h/ml. All 15 L. pneumophila-infected guinea pigs treated with gemifloxacin (10 mg/kg/dose given i.p. once daily) for 2 days survived for 9 days after antimicrobial therapy, as did 13 of 14 guinea pigs treated with the same dose of gemifloxacin given for 5 days. All 12 azithromycin-treated animals (15 mg/kg/dose given i.p. once daily for 2 days) survived, as did 11 of 12 animals treated with levofloxacin (10 mg/kg/dose given i.p. once daily for 5 days). None of 12 animals treated with saline survived. Gemifloxacin is effective against L. pneumophila in infected macrophages and in a guinea pig model of Legionnaires' disease, even with an abbreviated course of therapy. These data support studies of the clinical effectiveness of gemifloxacin for the treatment of Legionnaires' disease.

THE EFFECT OF THYROTROPHIC HORMONE ON THE POTASSIUM CONTENT OF MUSCLE AND LIVER TISSUE AND ON THE BLOOD SUGAR LEVEL IN GUINEA PIGS

1964 ◽  
Vol 45 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Per Olof Gedda
Keyword(s):  
Thyroid Gland ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Blood Sugar Level ◽  
Previous Investigation ◽  
Striated Muscle ◽  
Potassium Content ◽  
Single Subcutaneous Injection ◽  
Thyrotrophic Hormone ◽  
Made In

ABSTRACT The investigation showed that a single subcutaneous injection of thyrotrophic hormone (TSH) in young guinea pigs does not produce any change in the potassium content of striated muscle or of the liver within 2 hours of the injection, but does induce hyperglycaemia within this period. In a previous investigation (Gedda 1960), it was demonstrated that an equally large dose of TSH produced a marked increase in the potassium content of the thyroid gland of the guinea pig within 2 hours. The observations made in the present investigation support the assumption that the increase in potassium in the thyroid gland is specific to the gland after stimulation with TSH and that the increase is not secondary to a primary hypoglycaemia.

scholarly journals In Vitro Activity of ABT-773 againstLegionella pneumophila, Its Pharmacokinetics in Guinea Pigs, and Its Use to Treat Guinea Pigs with L. pneumophila Pneumonia

2001 ◽  
Vol 45 (10) ◽  
pp. 2685-2690 ◽  
Author(s):  
Paul H. Edelstein ◽  
F. Higa ◽  
Martha A. C. Edelstein
Keyword(s):  
Guinea Pig ◽  
Legionella Pneumophila ◽  
Half Life ◽  
Guinea Pigs ◽  
Clinical Effectiveness ◽  
Drug Dose ◽  
Drug Induced ◽  
Time Curve ◽  
Legionnaires Disease

ABSTRACT The activity of ABT-773 was studied against extracellular and intracellular Legionella pneumophila and for the treatment of guinea pigs with L. pneumophila pneumonia. The ABT-773 MIC at which 50% of isolates are inhibited (MIC50) for 20 different Legionella sp. strains was 0.016 μg/ml, whereas the MIC50s of clarithromycin and erythromycin were 0.032 and 0.125 μg/ml, respectively. ABT-773 (1 μg/ml) was bactericidal for two L. pneumophila strains grown in guinea pig alveolar macrophages. In contrast, erythromycin and clarithromycin had easily reversible static activity only. Therapy studies of ABT-773 and erythromycin were performed with guinea pigs with L. pneumophilapneumonia. When ABT-773 was given to infected guinea pigs by the intraperitoneal route (10 mg/kg of body weight), mean peak levels in plasma were 0.49 μg/ml at 0.5 h and 0.30 μg/ml at 1 h postinjection. The terminal half-life phase of elimination from plasma was 0.55 h, and the area under the concentration-time curve from 0 to 24 h (AUC0–24) was 0.65 μg · h/ml. For the same drug dose, mean levels in the lung were 15.9 and 13.2 μg/g at 0.5 and 1 h, respectively, with a half-life of 0.68 h and an AUC0–24 of 37.0 μg · h/ml. Ten of 15 L. pneumophila-infected guinea pigs treated with ABT-773 (15 mg/kg/dose given intraperitoneally once daily) for 5 days survived for 9 days post-antimicrobial therapy, as did 14 of 15 guinea pigs treated with erythromycin (30 mg/kg given intraperitoneally twice daily) for 5 days. All of the ABT-773-treated animals that died appeared to do so because of drug-induced peritonitis rather than overwhelming pneumonia. None of 12 animals treated with saline survived. ABT-773 is as effective as erythromycin against L. pneumophila in infected macrophages and in a guinea pig model of Legionnaires' disease. These data support studies of the clinical effectiveness of ABT-773 for the treatment of Legionnaires' disease.

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