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Summary The level of thyroid hormones in the thyroid glands of Egyptian buffaloes at various reproductive stages was determined by a radioactive technique. The results indicate no significant difference between the various stages of pregnancy. In inactive ovaries the ratio of iodothyronins to iodotyrosines is high. In pregnancy the middle stage shows a higher ratio of iodotyrosine to iodothyronine but this is not significant due to the small number of animals used. There was a highly significant difference between the two types of hormone in the case of metestrus and a moderately significant difference in preostrus and oestrus, while this difference was insignificant in the dioestrous stage. Identification of the thyroid metabolites was achieved by a radioactive method using 125I for in-vitro labelling of iodotyrosines and ***iodothyronines on paper chromatograms. Zusammenfassung Der Thyroxingehalt der Schilddruse von Haustieren VIII. Schilddrusenhormonspiegel in der Schilddruse des agyptischen Buffels wahrend verschiedener Phasen der Fortpflanzung Die Schilddrusenhormonmengen wurden mittels radioaktiver Isotope (125J) bestimmt. In den verschiedenen Graviditatsphasen wurden keine signifikanten Unterschiede festgestellt. In Phasen inaktiver Ovarien ist das Verhaltnis der Iodthyronine zu den Iodtyrosinen hoch. Wahrend der Graviditat ist der Quotient des Iodtyrosins zum Iodthyronin hoher, der Unterschied ist jedoch nicht signifikant. Hochsignifikante Unterschiede der beiden Schilddrusenstoffe wurden wahrend des Metoestrus und leichtsignifikante Unterschiede wahrend des Prooe-strus und Oestrus gefunden. Wahrend des Dioestrus war der Unterschied nicht signifikant. Resume Taux de la thyroxine dans la glande thyroide des animaux domestiques VIII. Taux de la thyroxine thyroidienne chez le buffle egyptien pendant les periodes de reproduction La quantite de l'hormone thyroidienne a ete determinee a moyen d'un isotope radioactif (125J). On n'a pas etabli de differences significatives dans les diverses periodes de la gestation. Le rapport jodthyronine et jodthyrosine fut eleve dans la periode de repos ovarien. Ce rapport fut plus eleve durant la gestation, mais la difference n'etait pas significative. On a trouve des differences hautement significatives des deux substances pendant le metoestrus et legerement significatives durant le prooestrus et l'oestrus. La difference ne fut pas significative pendant le dioestrus. Resumen Contenido de los tiroides en tiroxina en los animales domesticos VIII. Nivel hormonal tiroideo en el tiroides de la bufala egipcia durante las fases diversas de reproduccion Las cantidades de hormona tiroidea se valoraron mediante isotopos radio-activos (125I). En las diversas fases de gravidez no se apreciaron diferencias significantes. En las fases de ovarios inactivos es muy elevada la relacion entre las yodotironinas y las yodotirosinas. Durante la gestacion es mayor el cociente de yodotirosina a yodotironina, aunque la diferencia no es significativa. Se hallaron diferencias altamente significantes en ambas substancias tiroideas durante el metoestro y diferencias ligeramente significantes durante el prooestro y oestro. La diferencia no era significativa durante el dioestro.

1. 1. The effect of adenosine separately or in combination with alpha-1 adrenergic antagonist prazosin and alpha-2 adrenergic antagonist yohimbine as well as adenosine antagonists 8-phenyltheophylline and xanthine amine conjugate on glucose-induced insulin secretion from isolated rat pancreatic islets was studied. 2. 2. Their in vivo effects on serum glucose and insulin levels were also investigated. Adenosine at 10 and 100 μM inhibited significantly, insulin secretion from the isolated islets whereas at 10 mM slightly increased the secretion of insulin. 3. 3. Prazosin used at 100 μM inhibited insulin secretion. When it combined with adenosine (10 μM) it augmented the inhibitory effect of adenosine. 4. 4. In vivo prazosin (21 mg/kg bodywt) caused a hyperglycaemia which was accompanied by hypoinsulinaemia. 5. 5. Concurrent administration of this drug with adenosine neither affect the hyperglycaemic nor the hypoinsulinaemic effects of adenosine. 6. 6. On the other hand, yohimbine (100 μM) has no effect neither separately nor in combination with adenosine (10 μM) in modulating the inhibitory effect of adenosine on insulin secretion. 7. 7. When Yohimbine administered at 19.5 mg/kg body wt it did not alter serum glucose but it markedly increased the serum insulin level. Its combined administration with adenosine reduced the hyperglycaemic effect of adenosine with a remarkable increase in serum insulin. 8. 8. Both adenosine-antagonists were ineffective in alteration of insulin secretion. 9. 9. However, combination of 8-phenyltheophylline with adenosine (10 μM) totally blocked the inhibitory effect of adenosine on insulin secretion while xanthine amine conjugate failed to prevent this effect of adenosine. 10. 10. These results indicate that the inhibitory effect of adenosine on insulin secretion is neither mediated via alpha-1 nor alpha-2 adrenoceptors. It might be via activation of specific adenosine receptors on rat islets which are sensitive to blockade by 8-phenyltheophylline.

The present work was performed to study the effect of two calcium channel antagonists, namely verapamil (CAS 52-53-9) and nifedipine (CAS 21829-25-4) in modifying the inhibitory influence of adenosine on insulin secretion from isolated rat pancreatic islets. The combined effect of adenosine and these agents on serum insulin and glucose levels in vivo was also investigated. Both verapamil and nifedipine at 100 mumol/l and 1 mumol/l, respectively, produced a significant inhibition of glucose-stimulated insulin secretion from pancreatic islets. Combination of these agents with adenosine 10 mumol/l did not modify the inhibitory effect of adenosine on insulin secretion. Verapamil (21.6 mg/kg b.wt.) and nifedipine (5.4 mg/kg b.wt.) intraperitoneally injected prior to glucose loading produced a significant increase in serum glucose with an accompanied decrease in serum insulin levels. Concurrent administration of verapamil with adenosine neither affected the hyperglycaemic nor the hypoinsulinaemic effects of adenosine, whereas combined administration of nifedipine and adenosine decreased the hyperglycaemic effect of adenosine but not its hypoinsulinaemic effect. These results may indicate that these calcium channel antagonists do not interact with adenosine receptors which mediate its inhibitory effect on insulin secretion.

A method for free thyroxine estimation in serum, using labelled thyroxine and Sephadex G-25 has been developed. The experiment has been carried out by incubating labelled thyroxine with serum samples and separating the free thyroxine from bound protein in the serum by gel filtration after complete equilibrium between exogenous and endogenous thyroxine. Factors affecting the free thyroxine ratio such as volume of serum used, concentration of labelled thyroxine, time and temperature of incubation were studied and the optimum conditions for the test were selected. The sensitivity of the technique was determined by carrying out twelve estimations of the free thyroxine ratio on samples of pooled normal serum, pooled hypothyroid serum, and pooled hyperthyroid semm. In addition free thyroxine ratio leas determined for 23 hypothyroidisms, 99 euthyroid patients, 40 untreated thyrotoxicosis and 50 normal serum samples. A good correlation with the thyroid status of the patients (as determined) clinically and with ra...

Specific method for direct radioimmunoassay of IRP and IRI separately in human plasma has been described. The method is used for extraction of total insulin and separation of IRP from IRI by paper chromatography to be assayed separately. The separation of the two components are indentified and confirmed by column chromatography, paper chromatography and U.V. spectral analysis in comparison with the standard compounds. 134 plasma samples of different cases were, investigated for determination of IRI, IRP and IRT, of which 39 normals, 16 normal obes, 21 juvinil diabetes, 18 adult oncet diabetes, 10 recent adult diabetes, 12 hypothroid and 18 bilharzial hepatosplenomegaly to evaluate the levels of the test in comparison with blood sugar concentration.

A precise and accurate method is being developed for the determination of T3/T4 ratio. This method depends on using serum of different thyroid cases for the assesment of T3/T4 ratio. It has been found that the best temperature of storage is 0.0 °C to 4 °C before extracting the iodinated tyrosines and thyronines. Iodination with 125I was done according to our previous technique to render the separated thyronine radioactive. Scanning method helped for the determination of T3/T4 ratio. The results were confirmed by sensitivity and recovery test and statistically analyzed. 100 cases were investigated comprising hypo-, eu-, and hyperthyroid cases.

Specific method for accurate radioimmunoassay of free and total thyroxine in un-extracted serum has been developed. The method is used for estimation of either free thyroxine (T4) or total T4 by inhibition of the binding sites of T4 to protein using TCA/NaOH mixture. The antibodies used in this study were obtained from Mallinkrodt. The separation technique used in our modification is that of dextran charcoal, this is to absorb the free fractions on charcoal. The kinetics of antibody antigen combination, the parameters of the experiment like; charcoal concentration, antibody dilution, temp., time of incubation and radioactivity concentration were, studied to optimize the standard curve and the sensitivity of T4RIA. Serum samples of different thyroid cases were investigated for determination of free and total T4 concentration to get the levels for each group of which 50 normals, 57 hyperthyroidism and 21 hypothyroidism in comparison with the classical tests of thyroid functions. Also sensitivity and varianc...

Specific method for accurate radioimmunoassay (RIA) of total triiodothyronine (T3) in unextracted human serum has been developed. The method is used for estimation of either free T3 in serum or total T3 by inhibition of the binding sites of T3 to protein using TCA/NaOH mixture. The technique used is RIA, using T3-antibodies from Amersham and dextran charcoal is used for separation of free fraction from the bind antibody antigen protein. The kinitics of antibody antigen complination, the parameters of the experiment like charcoal concentration, antibody dilution and radioactivity concentration were studied to optimize the standard curve of T3 RIA. Serum samples of different thyroid cases were investigated for determination of total T3 concentration to gel the levels of T3 concentration for each group of which 50 normals, 57 hypothyroidism and 57 hyperthyroidism in comparison with the classical tests of thyroid functions. Also sensitivity and variance coefficient of the modified technique has been carried o...

Der Ascorbinsauregehalt von funf Leguminosen, namlich Vicia faba, Vigna sinensis, Phaseolus vulgaris, Trigonella foenum graecum und Lupinus termis, wird angegeben. Die durchschnittliche Veranderung im Vitamin C-Gehalt der Samen wahrend der Keimung wird aufgezeigt. Die Auswirkung von β-Strahlen, die kleine Mengen von radioaktivem H3 32PO4 aussenden, sowie die der γ-Strahlung von radioaktivem131J,137Cs oder60Co auf die Keimlinge wird beschrieben.

Es wird die Wirkung der Bestrahlung von wasrigen Losungen derl-Ascorbinsaure durch γ-Strahlen verschiedener Intensitaten zwischen 10 000 und 100 000r aufgezeigt. Als Strahlenquelle dientl-Ascorbinsaure in wasriger Losung durch ionisierende Strahlen wird beschrieben.

125I was used for labelling honey bee venom before fractionation on Sephadex G-25 and Sephadex G-100. Both radioactivity and extinction curves denoted the presence of four well defined peaks. The toxicity of the first peak was found to be the lethal one, for mice. While the other successive three peaks proved to be nontoxic to both mice and rats, up to a dose of 197.76 mg/kg body weight, and 241.11 mg/kg body weight respectively.

Labelling the venom of scorpion was achieved by means of a technique previously published by the author. The radioisotopes, used were both 125I and 131I in a nascent form. Fractionation was done by the use of Sephadex G-100. Both the radioactivity and the extinction curves denoted the presence of three well defined peaks. The toxicity of the first fraction was found to be the most lethal. While the second peak was in the magnitude of 20 percent of the first, the third peak proved to be nontoxic to mice up to a concentration of 6 mg/kg body weight.

In-vitro-labelling of vasopressin and tofranil using radioactive iodine and lechnelium, is carried out by direct interaction between nascent halogen and the macromolecules. Labelling takes place at the favourable pH in the tyrosyl residue of the molecule, yielding a die-iodo derivative or similar. The present method had the advantage of being simple rapid and gives labelled compounds of high specific activity. The gel-filtration method furnished labelled compounds with a minimum degradation products.

The results of this work have revealed that riboflavin content is diminished by irradiation with γ-rays. The more the dose and the longer the time of irradiation the more the effect on riboflavin solution. Addition of other materials as ascorbic acid, starch, and thiourea as radioprotectors to riboflavin solution, caused a decrease in the percentage loss, ranging from 12.5 — 86%. Thiourea used as protector in a ratio, 1:1 – riboflavin: thiourea, gave the best result especially with lower doses of radiation.

The ascorbic acid content of three types of Gramineae, viz., Triticum vulgare, Hordeum vulgare and Zea mays (Nab El-Gamal and Beladi), is given and also the average variations in the seeds during germination are shown. The effects on the seedlings of β-irradiation emitted from small doses of radioactive H332PO4 as well as by irradiation with 131 I, are investigated.

Summary 1 Deficiency of vitamin C in the diet of chickens depressed the activity of the thyroid gland, as detected by radioiodine uptake. 2 The activity of the thyroid of chickens depends not only on its content of vitamin C., but also on the dose of the vitamin C supplement fed to the chickens. 3 A dose of 100 mg. per kilogram diet restored the thyroid function of chickens while a dose of 50 mg did not. 4 Data are shown in tables and figures of thyroid activity, serum uptake and percentage of tyrosine and thyronines, by the use of 125I injected intraperitoneally in chickens. Zusammenfassung Die Wirkung von Vitamin C auf die Schilddrusenaktivitat bei Kuken 1 Vitamin-C-Mangel im Kukenfutter vermindert die Schilddrusenaktivitat (Untersuchung mit Hilfe der Radiojodaufnahme). 2 Die Schilddrusenaktivitat der Kuken hangt von der Dosis der Vitamin-C-Supplementierung des Futters ab. 3 Eine Vitamin-C-Dosis von 100 mg/kg Futter stellte die Schilddrusenfunktion wieder her, wahrend das bei einer Dosis von 50 mg nicht der Fall war. 4 Anhand von tabellarischen und grafischen Darstellungen wird die Schilddrusenaktivitat sowie die Aufnahme von Tyrosin und von Thyroninen in das Blut bei intraperitonealer Applikation von 125J dargestellt. Resume Action de la vitamine C sur l'activite de la glande thyroide chez des poussins 1 Le manque de vitamine C dans la nourriture diminue l'activite de la glande thyroide chez les poussins (recherche faite a l'aide de iode radioactif). 2 L'activite de la glande thyroide depend chez les poussins de la dose en vitamine C additionnee dans l'alimentation. 3 Une dose de 100 mg de vitamine C par kilo d'aliment remet en fonction la glande thyroide, ce qui n'est pas le cas avec 50 mg. 4 On a represente graphiquement et avec des tableaux l'activite de la glande thyroide ainsi que la presence de tyrosine et de thyronine dans le sang au moyen d'application intraperitoneale de 125J. Resumen La accion de vitamina C sobre la actividad tiroidea de los pollitos 1 La deficiencia vitaminica C en el pienso para pollitos disminuye la actividad tiroidea (experiencia con ayuda de yodo radiactivo). 2 La actividad tiroidea de los pollitos depende de la dosis del suplemento vitaminico C en el pienso. 3 La dosis de 100 mg. vitamina C por kilo de alimento restablecia la funcion de la glandula tiroidea, mientras que una dosis de 50 mg. no lo hacia. 4 A la vista de representaciones tabulares y graficas, se expone la actividad tiroidea, y la toma de tirosina y de tironina por la sangre con la aplicacion intraperitoneal de 125J.

The effect of crude prostaglandins extraced from prostate glands of camels as well as that PGE1, on the thyroid activity of male immature Boskat rabbits, was investigated. The iodinated amino acid fractions (T1, T2, T3 and T4) in the serum of the injected groups were determined in control and treated animals. Cytological work on sections of the thyroid glands of the treated and control rabbits were performed to study the effect on subcellular level. The results indicate that both crude and pure prostaglandins have a stimulating effect on thyroid activity. This was indicated by the increased 125I uptake of the thyroids of rabbits and evidenced histologically. PGE1, was found to be more effective as compared with the crude prostaglandins. The indinated amino acid and hormone fractions in the serum of the treated groups showed that T2 was increased as a result of injection of the crude prostaglandins, and T4 was increased after PGE1 injection. Tables and figures explained diversed effect.