FUNCTIONAL HETEROGENEITY OF THE THYROID AND POSSIBLE PRESENCE OF IODOTYROSINE-LIKE COMPOUNDS IN NORMAL SERUM

1965 ◽  
Vol 48 (2) ◽  
pp. 199-208 ◽  
Author(s):  
J. D. Wiener
Keyword(s):  
Human Subjects ◽  
Thyroid Tissue ◽  
Normal Serum ◽  
Schematic Model ◽  
Functional Heterogeneity ◽  
Rat Serum ◽  
Iodine Metabolism ◽  
Normal Rat ◽  
Isotope Equilibrium ◽  
Equilibrium Experiment

ABSTRACT After the administration of 131I to normal animals or human subjects, labelled thyroxine and triiodothyronine, but at most traces of labelled iodotyrosines can be detected in the serum. However, several investigators using various methods claim to have found considerable amounts of one or both of these iodotyrosines when assaying the stable (non-radioactive) iodinated compounds in the serum. Considering the available evidence as convincing for the present, an attempt has been made to explain this discrepancy. A schematic model of the thyroidal iodine metabolism is proposed, based on (a) the hypothesis that the iodotyrosines are present in the circulation in a »masked« form (i. e. protected against deiodination), and (b) the known functional heterogeneity of the thyroid tissue. This heterogeneity should be of a qualitative as well as quantitative nature. As the physical decay rate of 131I is short in comparison with the turnover rate of the masked iodotyrosine pool, an isotope equilibrium experiment with rats was carried out, using the long-lived isotope 125I. The results of this experiment, viewed together with those of a similar investigation published by others, seem to lend support to the proposed mechanism. The presence of non-negligible amounts of a diiodotyrosine-like compound in normal rat serum seems fairly well established.

scholarly journals Extraction of an Erythropoietin-Producing Factor from a Particulate Fraction of Rat Kidney

Blood ◽  
1966 ◽  
Vol 28 (3) ◽  
pp. 330-343 ◽  
Author(s):  
JOSEPH F. CONTRERA ◽  
ALBERT S. GORDON ◽  
ARTHUR H. WEINTRAUB
Keyword(s):  
Rat Kidney ◽  
Deae Cellulose ◽  
Mitochondrial Fraction ◽  
Normal Serum ◽  
The Other ◽  
Step Method ◽  
Renal Vasculature ◽  
Rat Serum ◽  
Normal Rat ◽  
Strong Resemblance

Abstract 1. A two-step method for the extraction of erythropoietin from hypoxic kidneys has been developed which allows residual plasma erythropoietin in renal vasculature to be separated from that of intracellular origin. 2. Renal extracts have been purified by DEAE cellulose chromatography and found to contain 2 major erythropoietically active fractions. One bears strong resemblance to plasma erythropoietin. The other component is unique in that it has practically no erythropoietic-stimulating activity unless previously incubated with normal rat serum. This activation phenomenon is used to identify this kidney component as the renal erythropoietic factor (REF). The REF has the capacity to produce erythropoietin or become erythropoietically active when incubated with normal rat serum. 3. Differential centrifugation technics revealed that the REF is confined to particles present in the light mitochondrial fraction of kidney. 4. Extracts of the light mitochondrial fraction of kidneys from normal rats produced significant amounts of erythropoietin when incubated with normal serum. The quantity found, however, was less than that evoked by similar extracts of kidneys from hypoxic rats. 5. The product of the incubation extracts of the renal light mitochondrial fraction with normal rat serum showed the same log dose/response regression as sheep plasma erythropoietin standard. 6. It is hypothesized that either (a) the REF is a precursor of erythropoietin which must be complexed with a carrier present in normal serum in order to become physiologically active, or (b) the renal factor is an enzyme which produces erythropoietin by its action on a particular serum protein.

Changes of serum thyroid hormone levels induce malformations on early embryogenesis in rats

1989 ◽  
Vol 121 (5) ◽  
pp. 739-743 ◽  
Author(s):  
Seijiro Harakawa ◽  
Shoichi Akazawa ◽  
Mihoko Akazawa ◽  
Masumi Hashimoto ◽  
Shunichi Yamashita ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Normal Serum ◽  
Early Embryogenesis ◽  
Rat Embryo ◽  
Thyroid Status ◽  
Rat Serum ◽  
Fetal Malformations ◽  
Normal Rat ◽  
Maternal Thyroid ◽  
Rat Embryo Culture

Abstract. The incidence of malformation is increased in infants of hyperthyroid or hypothyroid woman. Although many papers reported that the fetus is insulted from maternal thyroid hormone, the placenta (maternalfetal barrier) is not yet fully developed before 11.5 days of gestation in rat embryos, suggesting the effect of thyroid hormone on early rat embryogenesis. This study was, therefore, undertaken to investigate whether excess or lack of thyroid hormones would affect early embryogenesis in rat embryo culture. Malformations including open neuropore and microencephaly were observed in 10 of 30 embryos incubated in hyperthyroid serum, and in 12 of 42 cultured in T3-enriched normal serum. Similar malformations were observed in 14 of 42 embryos cultured in hypothyroid serum and in 10 of 30 cultured in hypothyroid serum supplemented with T3. The frequencies of these malformations were significantly higher than in the control embryos (0 in 72 embryos) cultured with normal rat serum. These results suggest that the maternal thyroid status might play an important role for the complication of fetal malformations during early gestational period.

THE SERUM HALF-LIFE OF SOMATOMEDIN ACTIVITY: EVIDENCE FOR GROWTH HORMONE DEPENDENCE

1976 ◽  
Vol 83 (2) ◽  
pp. 243-258 ◽  
Author(s):  
Kenneth L. Cohen ◽  
S. Peter Nissley
Keyword(s):  
Growth Hormone ◽  
Half Life ◽  
Thymidine Incorporation ◽  
Analysis Data ◽  
Normal Serum ◽  
Rat Serum ◽  
Thymidine Incorporation Assay ◽  
Hypophysectomized Rats ◽  
Normal Rat ◽  
Incorporation Assay

ABSTRACT The serum half-life of somatomedin (SM) activity has been measured following the intravenous injection of SM activity into hypophysectomized rats. A [3H]thymidine incorporation assay in chick embryo fibroblasts (CEFs) has been utilized to measure SM activity. Cell cycle analysis data obtained with the flow microfluorometer shows that the [3H]thymidine incorporation data reflects actual DNA synthesis. When normal rat serum was injected, a half-life for SM activity of approximately 3 h was determined. In marked contrast, when serum from hypophysectomized (hypox) rats acutely treated with growth hormone (GH) was used as the source of SM actively, the half-life of the SM actively was short, approximately 8 min. However, when serum from hypox rats chronically treated with GH was injected, the half-life was again long, approximately 4 h. SM activity has been separated from its binding proteins by boiling under acid conditions or chromatography on Sephadex G-50 in 1 n acetic acid. The halflife of this partially purified SM activity was short, in the range of 10–30 min. Finally, recombination of the partially purified SM activity with the large proteins in normal serum extended the half-life of the SM from 10–30 min to about 2 h. These data indicate that the serum half-life of SM activity is GH dependent and suggest that the serum binding protein, like SM itself, is under GH control.

The effect of epidermal growth factor, insulin and transferrin on the growth-promoting properties of serum depleted by repeated culture of postimplantation rat embryos

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 137-145
Author(s):  
M.K. Pratten ◽  
A.M. Brooke ◽  
S.C. Broome ◽  
F. Beck
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Promoters ◽  
Small Molecular Weight ◽  
Rat Serum ◽  
Rat Embryos ◽  
Partial Restoration ◽  
Normal Rat ◽  
Epidermal Growth ◽  
Growth Promoting

Homologous serum, when repeatedly used for the culture of postimplantation rat embryos, rapidly loses its capacity to support growth and development. Replenishment of the ‘exhausted’ serum with glucose and vitamins (MEM vitamin concentrate—Flow Laboratories) together with gentle dialysis to remove small molecular weight toxic metabolites (lactate etc) fails to restore the growth-promoting properties of the serum. This suggests that ‘recycled’ serum has been depleted of specific growth-promoting factors. Such serum that has been subjected to dialysis can be completely replenished by addition of 30% normal rat serum. It is therefore probable that the growth promoters are originally present at very low concentrations and become rate limiting when serum is recycled. Many growth factors and hormones fall into this category and it is likely that a considerable number are involved when serum is ‘exhausted’ by repeated use. When insulin, epidermal growth factor or rat transferrin are added to dialysed ‘exhausted’ serum each effects a partial restoration of growth of rat embryos.

The trichomonacidal factor in normal rat serum

1998 ◽  
Vol 47 ◽  
pp. 362
Author(s):  
Y Yabu ◽  
M Kunimatsu ◽  
T Koide ◽  
K Goto ◽  
H Okada ◽  
...  
Keyword(s):  
Rat Serum ◽  
Normal Rat

A COMPARISON OF RAT AND RABBIT SERA BACTERICIDINS ACTIVE AGAINST STAPHYLOCOCCI

1967 ◽  
Vol 13 (7) ◽  
pp. 885-894 ◽  
Author(s):  
W. W. Yotis ◽  
J. S. Ortiz
Keyword(s):  
Antibacterial Activity ◽  
Staphylococcus Epidermidis ◽  
Antibacterial Agent ◽  
Sodium Citrate ◽  
Staphylococcal Infection ◽  
Rabbit Serum ◽  
Rat Serum ◽  
Normal Rat ◽  
Marked Resistance ◽  
Better Than

The respiration and growth of 5 strains each of Staphylococcus aureus and Staphylococcus epidermidis in fresh normal rat and rabbit sera were measured. S. aureus grew and oxidized the sera of these animals better than S. epidermidis. Both S. aureus and S. epidermidis grew and respired more actively in rabbit than in rat serum. The antibacterial activity of rat or rabbit serum was stable to heating at 56 °C for 1 h, but its activity was destroyed after heating at 60 °C for 2 h. Treatment of rat and rabbit sera with 0.4 M sodium citrate drastically reduced the antibacterial activity of these sera. Once the sera had been treated with sodium citrate or oxalate, addition of equimolar solutions of calcium chloride or magnesium chloride failed to restore the antibacterial activity of rat and rabbit sera. Addition of ferric ions at concentrations which are not normally found in rat and rabbit sera reversed the inhibitory activity of these sera, thus allowing coagulase-negative strains of staphylococci to grow well in rat and rabbit sera. The antibacterial agent of rat or rabbit serum was absorbed by heat-killed cells of S. aureus and S. epidermidis; treatment with bentonite at a concentration of 100 mg/ml absorbed the antibacterial agent from rabbit serum but only partially from rat serum. The high levels of the antibacterial agent in rat serum may explain the partial removal of this agent by bentonite and may contribute to the marked resistance of the rat to staphylococcal infection.

The Properties of Soluble Proteins Synthesized by Nephrotic Rat Kidney Microsomes

1972 ◽  
Vol 50 (3) ◽  
pp. 292-298
Author(s):  
V. N. Katiyar ◽  
B. L. Dinh
Keyword(s):  
Gel Electrophoresis ◽  
Rat Kidney ◽  
Periodic Acid ◽  
Rabbit Antiserum ◽  
Periodic Acid Schiff ◽  
Rat Serum ◽  
Tissue Protein ◽  
Schiff Reagent ◽  
Normal Rat ◽  
Kidney Microsomes

The incorporation of 14C-leucine into the microsomal proteins of nephrotic rat kidney was much higher than that in the microsomal proteins of the normal rat kidney. When the newly synthesized microsomal proteins were analyzed by acrylamide gel electrophoresis, it was found that the higher incorporation of 14C-leucine in nephrotic rat kidney was mostly due to an increase in the biosynthesis of a tissue protein which migrated in the electrophoretic zone between serum albumin and transferrin. This protein did not react with rabbit antiserum to normal rat serum and was stained with periodic acid – Schiff reagent. It was believed to be excreted in the urine of nephrotic rats in great quantity and was easily identified as a distinct band in electrophoregrams of urine from these rats.

Enhancement of antimicrobial drugs by normal rat serum and pleural carrageenan exudate

1990 ◽  
Vol 22 ◽  
pp. 91-92
Author(s):  
P.A. Miglioli ◽  
P. Lanzafame ◽  
P. Sartore ◽  
M. Mazzo
Keyword(s):  
Antimicrobial Drugs ◽  
Rat Serum ◽  
Normal Rat

scholarly journals ANALYSIS OF THE PROTEINS OF RAT SERUM BY STARCH ELECTROPHORESIS AND BY CATIONIC DETERGENT ANALYSIS

1959 ◽  
Vol 110 (3) ◽  
pp. 341-353 ◽  
Author(s):  
Ralph F. Jacox
Keyword(s):  
Low Ph ◽  
Acetate Buffer ◽  
Electrophoretic Separation ◽  
Rat Serum ◽  
High Ph ◽  
Cationic Detergent ◽  
Normal Rat

A protein of unusual characteristics has been identified in normal rat sera by electrophoretic separation at pH 8.6, followed by precipitation of each fraction with a cationic detergent. This protein, which is closely identified with albumin after electrophoresis at pH 8.6, precipitates with cationic detergent at a low pH in contrast to albumin which precipitates with detergent only at a high pH. This protein has characteristics of a globulin and is designated as a "fast alpha fraction." This fraction and albumin are present in about equal amounts in sera of normal rats. A separation of the fast alpha fraction can be made by electrophoresis in an acetate buffer of pH 4.25 and by precipitation according to a modified Cohn, cold-alcohol technique. A protein of similar characteristics has not been found in either human or rabbit sera studied by the same method of electrophoresis and subsequent sub-fractionation with cationic detergent.

Sign in / Sign up

Export Citation Format

Share Document