DYNAMIC STUDY OF POST-NATAL THYROID FUNCTION IN THE RAT

1976 ◽  
Vol 83 (4) ◽  
pp. 752-762 ◽  
Author(s):  
E. Vigouroux
Keyword(s):  
Body Weight ◽  
Plasma Concentration ◽  
Thyroid Function ◽  
Rate Constant ◽  
Turnover Rate ◽  
Single Injection ◽  
Iodine Content ◽  
Adult Females ◽  
Maximal Plasma ◽  
Old Rats

ABSTRACT The thyroid function in development was investigated in post-natal rats. The thyroid iodine content rapidly increased from birth (137 ± 26 ng iodine/mg thyroid) up to day 10 (338 ± 42 ng iodine/mg thyroid) then increased more slowly up to day 30 (425 ± 34 ng iodine/mg thyroid). The maximal plasma concentration of thyroxine was observed on day 16 (56.9 ± 3.5 ng T4/ml) and of iodide on day 10 (110.2 ± 12.6 ng I−/ml). The turnover rate constant of extrathyroidal thyroxine was higher at birth (8.0 ± 2.3 %/h) than at any older age studied (average 6 %/h). Thyroxine secretion by the thyroid was more intense before weaning (37 ng hormonal iodine/h/100 g body weight on days 10 and 20) than after weaning (22 ± 6 ng hormonal iodine/h/100 g body weight in 30 days old rats). The peripheral deiodination rate of thyroxine represented about 90 % thyroxine secretion rate in newborn and 10 days old rats and only 40% in adult females. In pre-weaning rats, after a single injection of both [131I]L-T4 and [125I]Na, extrathyroidal radioactivity disappeared more slowly than in 30 days old rats and adult animals. This suggests that iodide concentrations of extrathyroidal tissues are higher before than after weaning.

Studies of the Toxicological Potential of Capsinoids, XI: Pharmacokinetic and Tissue Distribution Study of 14C-Dihydrocapsiate and Metabolites in Rats

2010 ◽  
Vol 29 (2_suppl) ◽  
pp. 3S-14S ◽  
Author(s):  
Bruce K. Bernard ◽  
Kazuyuki Ubukata ◽  
Ryuichi Mihara ◽  
Yoshiaki Sato ◽  
Hiroyuki Nemoto
Keyword(s):  
Body Weight ◽  
Plasma Concentration ◽  
Vanillic Acid ◽  
Male Rats ◽  
Vanillyl Alcohol ◽  
Tissue Concentrations ◽  
Distribution Study ◽  
Maximal Plasma ◽  
Tissue Distribution Study ◽  
Kidney Liver

Pharmacokinetics of a single gavage dose of 14C-labeled dihydrocapsiate (10 mg/kg) were investigated in male rats. Maximal plasma concentration was achieved in 40 minutes and exhibited an apparent half-life of 2.4 hours. Excretion of radioactivity in the urine, feces, and expired air was 78.2%, 19.4%, and 0.5% of the dose, respectively. Highest tissue concentrations were achieved in the kidney, liver, and blood; the data indicate that radioactivity accumulation following daily exposure at a dose of 10 mg/kg body weight is unlikely. Radioactivity in the plasma was associated with metabolites and their conjugates, probably vanillyl alcohol, vanillic acid, glucuronide of vanillyl alcohol, sulphate of vanillyl alcohol, and sulphate of vanillic acid. These results suggest dihydrocapsiate is metabolized by hydrolysis in the gut, or esterase or other enzymes in the blood, and the metabolites were rapidly absorbed and converted to their conjugates in the liver and eliminated by the kidneys into the urine.

The effect of a single injection of estradiol benzoate on thyroid function in intact male rats

1968 ◽  
Vol 46 (4) ◽  
pp. 697-700 ◽  
Author(s):  
K. Brown-Grant
Keyword(s):  
Body Weight ◽  
Thyroid Gland ◽  
Thyroid Function ◽  
Dose Level ◽  
Adult Male ◽  
Single Injection ◽  
Estradiol Benzoate ◽  
Male Rats ◽  
Intact Male ◽  
Federation Proc

The changes observed in the metabolism of radioiodide and radiophosphorus by the thyroid gland of intact adult male rats following a single injection of estradiol benzoate (4 μg/100 g body weight) are consistent with the suggestion (F. Labrie, G. Pelletier, and C. Fortier. Federation Proc. 26, 484 (1967). Abstr.) that at this dose level estrogen causes a hypersecretion of TSH in such animals.

THE TRANSPLACENTAL PASSAGE OF THYROXINE AND FOETAL THYROID FUNCTION IN THE RAT

1974 ◽  
Vol 75 (4) ◽  
pp. 725-733 ◽  
Author(s):  
Barry Gray ◽  
Valerie Anne Galton
Keyword(s):  
Body Weight ◽  
Thyroid Gland ◽  
Thyroid Function ◽  
Placental Transfer ◽  
Iodine Content ◽  
Perinatal Period ◽  
Maternal Serum ◽  
Transplacental Passage ◽  
Pregnant Rats ◽  
Near Term

ABSTRACT A study has been made of the transplacental passage of thyroxine (T4) in rats when the hormone is present in physiological concentrations, and of the activity of the foetal thyroid gland in the perinatal period. Several aspects of foetal thyroid function were assessed in intact and thyroid-ectomized (TX) pregnant rats maintained with graded doses of T4. A daily dose of 2 μg T4/100 g body weight yielded near normal maternal and foetal serum PBI levels; with a dose of 1 μg the values were slightly low. Both these doses resulted in a decrease in the total and T4 iodine content of the foetal thyroid; an even greater decrease occurred in rats maintained with 5 μg/100 g body weight/day. The rate of uptake of iodine by the foetal gland was significantly depressed by the 2 but not the 1 μg dose. Serum PBI levels in the foetus were related directly to the dose of T4 and inversely with the degree of depression of the thyroid gland. Both maternal and foetal serum PBI levels in the unsupplemented TX rats were at least 60 % of normal and there was evidence of increased secretion of T4 by the foetal thyroid. The data indicate that the placenta is readily permeable to T4 when the hormone is present in maternal serum in doses that are close to physiological. However it was not possible to estimate the extent of the placental transfer of endogenous hormone. Significant foetal thyroid function was evident near term. It is suggested that both the foetal and maternal thyroids contribute to the maintenance of serum T4 levels in the foetus.

Dietary iodine and thyroidal iodide transport in chickens: organic binding blocked.

1978 ◽  
Vol 234 (2) ◽  
pp. E177
Author(s):  
W S Newcomer
Keyword(s):  
Experimental Data ◽  
Protein Binding ◽  
Rate Constant ◽  
Experimental Error ◽  
Compartmental Model ◽  
Single Injection ◽  
Iodine Content ◽  
Exit Rate ◽  
Iodide Transport

Experimental data concerning the increase in T/S [I-] (ratio of concentration of radioiodide in thyroid to that in serum) during equilibration after a single injection of radioidide were obtained from chickens in which protein binding of radioidide was inhibted by methimazole. Equilibration data were obtained from chickens fed a low-iodine diet (2 mo) as well as the low-iodine diet to which various amounts of NaI had been added. Experimental data were compared with productions based on the open two-compartmental model of Wollman and Reed (Am. J. Physiol. 196: 113-120, 1959). Thyroidal clearance (C/m) of radioiodide (the rate at which radioiodide is transferred from blood into the thyroid and equal to the radioiodide content of C microliter serum per minute) varied inversely to iodine content of feed. Exit rate constant (KTB, the fraction of thyroidal radioiodide transferred to serum per minute) was relatively more constant. The experimental data fitted the predictions from the model within experimental error. Thirty days of feeding the low-iodine diet was required before C/m stabilized at 50 microliter/min per mg and KTB at 0.065; stabilization of C/m and KTB occurred in 12 days with the highest iodine diet.

THE »EARLY-ANDROGEN« SYNDROME; ITS DEVELOPMENT AND THE RESPONSE TO HEMI-SPAYING

1964 ◽  
Vol 45 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. E. Swanson ◽  
J. J. van der Werff ten Bosch
Keyword(s):  
Sexual Maturity ◽  
Compensatory Growth ◽  
Testosterone Propionate ◽  
Single Injection ◽  
Weight Increase ◽  
Corpora Lutea ◽  
Transition Stage ◽  
Adult Females

ABSTRACT The »early-androgen« syndrome in the rat – i. e. anovulatory ovaries in adult females after a single injection of testosterone propionate (TP) within a week of birth – may not become apparent until some time after the attainment of sexual maturity. Large doses (50 or 100 μg) of TP were effective earlier than lower doses (5 or 10 μg). Rats which received 5 μg TP were ovulating at 10 weeks of age, mated but were infertile at 13 weeks of age, and were anovulatory at 21 weeks. In rats between 10 and 13 weeks old there was a marked fall in the number of corpora lutea in the ovaries of animals which had been given 5 μg TP. Hemi-spaying was followed by compensatory growth of the remaining ovary which consisted of corpora lutea in ovulating, and of follicles in anovulatory rats; little or no compensatory weight increase occurred in animals which seemed to be in the transition stage from the ovulatory to the anovulatory condition.

scholarly journals Influence ofABCC2andABCC4Polymorphisms on Tenofovir Plasma Concentrations in Thai HIV-Infected Patients

2015 ◽  
Vol 59 (6) ◽  
pp. 3240-3245 ◽  
Author(s):  
Kanokrat Rungtivasuwan ◽  
Anchalee Avihingsanon ◽  
Narukjaporn Thammajaruk ◽  
Siwaporn Mitruk ◽  
David M. Burger ◽  
...  
Keyword(s):  
Body Weight ◽  
Multivariate Analysis ◽  
Plasma Concentration ◽  
Protease Inhibitors ◽  
Demographic Data ◽  
Plasma Concentrations ◽  
Multidrug Resistant ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
The Mean

ABSTRACTTenofovir (TFV) is eliminated by renal excretion, which is mediated through multidrug-resistant protein 2 (MRP2) and MRP4, encoded byABCC2andABCC4, respectively. Genetic polymorphisms of these transporters may affect the plasma concentrations of tenofovir. Therefore, the aim of this study was to investigate the influence of genetic and nongenetic factors on tenofovir plasma concentrations. A cross-sectional study was performed in Thai HIV-infected patients aged ≥18 years who had been receiving tenofovir disoproxil fumarate at 300 mg once daily for at least 6 months. A middose tenofovir plasma concentration was obtained. Multivariate analysis was performed to investigate whether there was an association between tenofovir plasma concentrations and demographic data, including age, sex, body weight, estimated glomerular filtration rate (eGFR), hepatitis B virus coinfection, hepatitis C virus coinfection, duration of tenofovir treatment, concomitant use of ritonavir-boosted protease inhibitors, and polymorphisms ofABCC2andABCC4. A total of 150 Thai HIV-infected patients were included. The mean age of the patients was 43.9 ± 7.2 years. The mean tenofovir plasma concentration was 100.3 ± 52.7 ng/ml. In multivariate analysis, a low body weight, a low eGFR, the concomitant use of ritonavir-boosted protease inhibitors, and theABCC44131T → G variation (genotype TG or GG) were independently associated with higher tenofovir plasma concentrations. After adjusting for weight, eGFR, and the concomitant use of ritonavir-boosted protease inhibitors, a 30% increase in the mean tenofovir plasma concentration was observed in patients having theABCC44131 TG or GG genotype. Both genetic and nongenetic factors affect tenofovir plasma concentrations. These factors should be considered when adjusting tenofovir dosage regimens to ensure the efficacy and safety of a drug. (This study has been registered at ClinicalTrials.gov under registration no. NCT01138241.)

Specific Susceptibility to HCN and the amount of HCN recovered from Fumigated Insects

1951 ◽  
Vol 42 (2) ◽  
pp. 399-418 ◽  
Author(s):  
S. Pradhan ◽  
S. C. Bhatia
Keyword(s):  
Body Weight ◽  
Water Content ◽  
Relative Position ◽  
Surface Resistance ◽  
Internal Resistance ◽  
Effective Resistance ◽  
The Body ◽  
Effective Dosage ◽  
Adult Females ◽  
The Dead

The relationship was studied between susceptibility of a number of different species of insects to HCN fumigation and the recovery of HCN from them immediately after fumigation.The test insects used were Tribolium castaneum, seventh stage caterpillars of Corcyra cephalonica, first-and second-instar nymphs of Drosicha sp., third-and fourthinstar nymphs of Drosicha sp. and adult females of Drosicha sp.The apparatus and methods used in the fumigation and in the recovery of HCN from the fumigated insects are fully described.Preliminary expsriments showed that the processes of distillation and redistillation did not affect the recovery of HCN but that the result obtained for recovery from distillation could be affected if some volatile reducing substance were produced and carried over to the distillate. It was found that this did actually take place in the case of one of the test insects—T. castaneum—but that redistillation got rid of the impurity.In the main experiments it was shown that, on the assumption that the concentration of HCN to which insects are exposed is the effective dosage, the susceptibility of the test insects varied in the following descending order : firstand second-stage nymphs of Drosicha sp. > third- and fourth-stage nymphs of Drosicha sp.>C. cephalonica> T. castaneum>the adult females of Drosicha sp.When the same insects were arranged in descending order of the quantities of HCN recovered per 100 gm. of body weight, the order was identical except for the nymphs of Drosicha sp. which occupied a different relative position. The two categories of nymphs of Drosicha sp. were found to occupy a different relative position again with regard to the other three test insects when exposed to a superlethal concentration and assessed for recovery of HCN per 100 gr. body weight.Parallel batches of T. castaneum and C. cephalonica were fumigated and the HCN was recovered from the dead and survivors. More HCN was recovered from the dead insects than from those that survived.Both recovery and sorption of HCN were estimated separately in parallel batches of insects (adult females of Drosicha sp. and C. cephalonica). Recovery was found to be less than sorption showing that a part of the HCN absorbed is converted into a non-recoverable state. Further, that the weight of HCN sorbed per gram body weight of adult females of Drosicha sp. is much less than in the case of C. cephalonica under similar conditions of fumigation and that the amount of HCN converted into non-recoverable products is less in Drosicha adults than in C. cephalonica.A comparison of the water content of T. castaneum, C. cephalonica and Drosicha sp. (adults) showed that there was a positive correlation between water content and higher susceptibility to HCN and greater recovery of HCN was also indicated. It is suggested that this may be a factor in the “ Surface Resistance ” of an insec to a fumigant.The observations of previous workers that larger amounts are sorbed by or recovered (after fumigation) from more susceptible species than for those less susceptible was corroborated by the results obtained with C. cephalonica, T. castaneum and adult females of Drosicha sp. but not with those from nymphs of Drosicha sp.When dosage-mortality graphs were prepared by taking the amount of HCN recovered per gram body weight as an index of internal dose, the order of resistance of different test insects based on this new criterion was found to be entirely different from that based on the usual criterion of the concentration of HCN in the fumatorium being the index of effective dosage.These apparently anomalous observations may be explained by assuming that the resistance shown by an insect in an actual fumigation operation, i.e., to the concentration of HCN to which it is exposed (external dose) is what may be called the total “ Effective Resistance ” and that this “ Effective Resistance ” is the resultant of (a) “ Surface Resistance ” to the entry of fumigant and (b) “ Internal Resistance ” to the amount of HCN which actually gains entry into the body in some way or other. Thus the “Effective Resistance ” of an insect may be due to a combination either of low “ Surface Resistance ” and high “ Internal Resistance ”, giving a very low “ Effective Resistance ” as in the case of C. cephalonica, or vice versa giving the maximum “ Effective Resistance ” as in adult females of Drosicha sp. The lower recovery of HCN from the nymphs of Drosicha sp., although they were more susceptible to fumigation than C. cephalonica, is explained by their higher “ Surface Resistance ” combined with a very much lower “ Internal Resistance ”, leading to a lower “ Effective Resistance ”.

Increase in Cell Number as a Factor in the Growth of the Organs and Tissues of the Young Male Rat

Development ◽  
1962 ◽  
Vol 10 (4) ◽  
pp. 530-562
Author(s):  
M. Enesco ◽  
C. P. Leblond
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Room Temperature ◽  
Young Male ◽  
Cell Number ◽  
The Body ◽  
Male Rat ◽  
The Past ◽  
Old Rats ◽  
Young Rat

While the organs and tissues of the young rat are known to increase in size with age (Donaldson, 1924), little is known of the role played by the component cells in this increase. There is evidence that cells enlarge (Levi, 1906; Plenk, 1911) and new cells are added (Strasburger, 1893), but we do not know to what extent the enlargement and proliferation of the cells cause the growth of organs and tissues. The present work is an attempt to clarify this problem. In the past, the growth of organs and tissues has often been measured by weight gain (Donaldson, 1924). However, this approach might be misleading, since the body-weight may increase in the absence of growth, for instance as a result of fat-storage in old rats, of pregnancy in females, and even of changes in room temperature.

scholarly journals The Influence of Age, Sex, Pregnancy, Starvation, and Other Factors on the Cytoplasmic Ribonucleoproteins of Rat Liver

1958 ◽  
Vol 4 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Mary L. Petermann ◽  
Mary G. Hamilton
Keyword(s):  
Body Weight ◽  
Rat Liver ◽  
Liver Tissue ◽  
Microsomal Protein ◽  
Male Rats ◽  
Differential Centrifugation ◽  
Adult Males ◽  
Analytical Ultracentrifuge ◽  
Total Rna ◽  
Adult Females

Rat liver was homogenized in 0.88 M sucrose. The DNA and total RNA were determined, and the homogenate was fractionated by differential centrifugation. The pellets obtained between 30 minutes at 20,000 g and 180 minutes at 105,000 g were analyzed for RNA and nitrogen. The ribonucleoproteins were determined in the analytical ultracentrifuge. The non-pellet RNA was calculated by difference. The results are reported as amounts per 6.7 x 10-9 mg. of DNA. In young, growing male rats the amounts of microsomal protein and ribonucleoprotein B (83S) increased with age. Non-pregnant adult females showed less non-pellet RNA and much more ribonucleoprotein C (63S) than did adult males. During pregnancy both of these cell constituents reverted to levels characteristic for male animals. Starvation for 5 days resulted in a reduction in the mass of liver tissue, the non-pellet RNA, the microsomal protein, and ribonucleoproteins B and C. During recovery from starvation the return of the liver to normal paralleled the rate at which body weight was restored. Treatment with cortisone, 25 mg. per rat per day for 5 days, caused an increase in microsomal protein and a decrease in ribonucleoprotein B. Treatment with 6-mercapto-purine, 50 mg. per kilo per day for 5 days, caused little change in liver composition in either males or females.

THYROID FUNCTION IN PROTEIN-DEPLETED RATS

1970 ◽  
Vol 46 (1) ◽  
pp. 93-99 ◽  
Author(s):  
W. H. FLORSHEIM ◽  
BIRUTA Z. SUHR ◽  
R. T. MIRISE ◽  
A. D. WILLIAMS
Keyword(s):  
Serum Albumin ◽  
Thyroid Function ◽  
Acid Content ◽  
Iodine Content ◽  
Protein Depletion

SUMMARY Renal iodide clearance in rats was reduced rapidly when the animals were fed a protein-depletion diet. If the iodine content of the protein-depletion diet is high, this results in an increase in the serum iodide levels to concentrations in excess of 150 μg./100 ml. Protein-bound iodine was elevated due to the accumulation of iodinated serum albumin. Thyroid hormonal iodoamino acid content was transiently depressed, presumably by the mechanism described by Wolff & Chaikoff (1948). Thyroxine metabolism was not affected except for a change in the partition of thyroxine between liver and serum. There was no evidence for pituitary involvement in the effects of protein depletion on thyroid function.

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