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O Földes

Publications and source records attributed to O Földes.

53 records · Page 3Linked to original sources
PubMed1980

Acute effect of salicylate on T4 and T3 levels in plasma and their excretion by bile in rats.

Male Wistar rats weighing about 400 g were anaesthetized with pentobarbiturate (40 mg kg-1) i.p. and thin polyethylene tubings were inserted in left femoral artery and vein as well as in a bile duct. Blood samples were taken at 30-60 min intervals for 6 h. The total bile was collected to pre-weighed glass vials. With the aid of radioimmunoassay the level of thyroxine (T4) and 3,5,3'-triiodothyronine (T3) was estimated in plasma and the total excretion of these compounds by bile was measured after the incubation of bile aliquots with beta-glucuronidase-arylsulphatase. After i.v. injection of sodium salicylate (S; 80 mg kg-1) a significant decrease of T4 and T3 in plasma was found compared either to the initial level found in the same animals or to that found in controls not injected with S. Total excretion of bile was increased within 2 h after the administration of S. Under these conditions, the excretion of T4 was increased, while that of T3 was decreased. It is suggested that the effect of salicylate under the experimental conditions used consists of: 1. displacement of iodothyronines from plasma protein binding; 2. increased bile excretion (during the initial period after the administration of S) presumably due to the increased blood flow through the liver.

Animals↗
PubMed1980

Studies on the effect of pentobarbiturate, ether and heparin on plasma thyroxine level in rats.

In groups of 9 to 20 adult male rats decapitated at 0, 15 or 60 min after i.p. injection of saline or at the same intervals after 2 min exposure to ether no differences in plasma thyroxine level were found. In groups of 5-6 animals a significant decrease of thyroxine level in plasma was observed at 30 min after i.p. injection of pentobarbiturate (40 mg kg-1) and unsignificant decrease after 800 and 2400 U heparin i.p. per animal. Finally, in 58 animals a linear decrease of plasma thyroxine level was found during 480 min beginning from about 60th to 90th min after the onset of pentobarbiturate anaesthesia (40 mg kg-1 followed by 20 mg kg-1 every 60-90 min). It was concluded that the blood clotting preventive dose of heparin (i.e. 300 U per 400 g animal) presumably does not interfere with the level of thyroxine in plasma, while pentobarbiturate apparently results in a considerable decrease of that.

Anesthetics↗
PubMed1979

Does a short-term draining of bile duct affect the plasma thyroxine level in rats?

In three groups of male rats weighing about 350 g and fed normal pelleted diet the left femoral artery and vein were cannulated under pentobarbiturate anesthesia and in samples of plasma obtained between 0 and 6 h after the injection of heparin the level of thyroxine (T4) was measured with the aid of specific radioimmunoassay. In addition, in Group A (22 animals) and C (17 animals) also the bile duct was cannulated and the total bile was collected into a flask for the same period. In addition, the animals of a Group C were thyroidectomized by electrocoagulation immediately before "O h". The Group B consisted of 18 sham-operated animals in which, in addition to the cannulation of blood vessels, only laparotomy and separation of bile duct without cannulation were made. In all groups a linear decline of plasma T4 level was found corresponding to a half-life of about 11 h. Since there were no significant differences in the slope of regression line between groups, it was concluded that the period of draining bile duct for 6 h was presumably too short to interfere significantly with the absorption of T4 in lower intestine and ileum and that the uniform decline of T4 level in plasma in all groups was presumably due to the effect of pentobarbiturate.

Animals↗
PubMed1978

Short-term effect of acetylsalicylic acid analogue on pituitary-thyroid axis and plasma cortisol level in healthy human volunteers.

The effect of acetylsalicylic acid analogue (aloxiprinum; Superpyrin Spofa) administered perorally in a daily dose of 1 g per 10 kg body weight on serum levels of free thyroxine (FT4), total thyroxine (T4), triiodothyronine (T3), cortisol (F) and thyrotrophin (TSH) was studied in healthy human volunteers. In a first experiment the drug was administered for 3 days to 7 subjects, the total daily dose being divided into 4-5 aliquots, while the same total dose was administered within 4 h to another 8 subjects in a second experiment. In both experiments a highly significant increase of FT4 was found during the period of treatment, while the levels of other hormones i.e. (T3, T4, F and TSH) were decreased, in most cases significantly. After the withdrawal of the drug there was not only a return of all levels to the initial value, but in most cases an "overshoot" above this value was detected.

Adult↗
PubMed1978

Lesions of some central nervous structures result in altered pituitary-thyroid response to acute decrease of blood thyroid hormone level.

Eight groups (3--6 animals each) of rats weighing 350--400 g were subjected to electrolytic lesions of various parts of habenular, thalamic and hypothalamic areas of brain. On the 6th day after the lesion the level of blood thyroid hormone was acutely decreased with the aid of isovolemic exchange transfusion (IET) of thyroid hormone free blood suspension. The level of thyroxine (T4) in plasma was measured before and during 180 min after IET with the aid of specific radioimmunoassay and the changes of its post-transfusion level were evaluated. It was found that in three groups of animals bearing large bilateral lesions either in lateral ventral thalamus or in a central inferior thalamus the response of T4 level during the post-transfusion period is similar to that found in intact control groups from previous experiments. This consists in an increase of T4 level nearly to the initial value within about 120--150 min after IET. In contrast, there was only a slight post-transfusion increase of T4 level in one group with small central lesion in medial superior thalamus and no increase in two groups bilaterally lesioned in habenular area and in another two groups lesioned either in a central part of dorsal hypothalamus or in a central dorsal part of ventral basal hypothalamus. It was concluded that some parts of brain may be involved in managing the appropriate response of pituitary-thyroid axis to acute decrease of thyroid hormone level, no plausible explanation of the mechanism ofthe observed phenomena being offered.

Animals↗
PubMed1977

Acute decrease of blood thyroid hormone by isovolemic exchange transfusion as a stimulus for pulse TSH release and its modifications by CNS Lesions.

The level of thyroid hormone in blood has been acutely decreased by about 20--30% within 20 min with the aid of isovolemic exchange transfusion (IET) of thyroid hormone free blood cell suspension (THFBCS) in three groups of rats: (1) intact control (C); (2) median eminence (ME)-lesioned; (3) thalamus (TH)-lesioned. The levels of thyroxine (T4) and TSH were measured by specific radioimmunoassay (RIA) before the transfusion and for 180 min after that. The level of T4 increased to the initial value at about 120 min after IET in C and ME-lesioned rats, while in TH it remained decreased until 180 min. Furthermore, at the end of IET the level of TSH in C and ME-lesioned rats was about 2--3 time higher than the initial value and its continuous decrease was observed until 180 min. In contrast, in TH-lesioned rats the increase of TSH level was delayed, being significant at 60 min only. It was concluded that IET of THFBCS acts as a stimulus of acute TSH release which was remarkably inhibited in TH-lesioned animals. In addition, the destruction of most of the ME did not apparently influence this response, as shown by essentially similar data obtained in C and ME-lesioned rats.

Animals↗
PubMedDate not supplied

Effect of adrenaline on biliary excretion of triiodothyronines in rats mediated by alpha 1-adrenoceptors and related to the inhibition of 5'-monodeiodination in liver.

Biliary excretion of thyroxine (T4),3,5,3'-triiodothyronine (T3),3,3,5'-triiodothyronine (rT3) and diiodothyronines (3,3'-T2,3,5-T2 and 3',5'-T2) was estimated with the aid of radioimmunoassay in 3-4 subsequent 2-h samples of bile obtained from pentobarbital anesthetized rats through the tubing inserted in bile duct. The excretion of T3 was significantly decreased during 4-h infusion of 2400 ng/kg/min adrenaline in normal rats or during 6-h infusion of the latter dose in the animals preinjected with 2 micrograms T4. Moreover, the excretion of rT3 was significantly increased after the infusion of 1200 and 2400 ng/kg/min adrenaline. Such increase after 1200 and 2400 ng/kg/min adrenaline was prevented by a single dose of 10 mg/kg phentolamine (alpha 1-2-antagonist) and that after 2400 ng/kg/min adrenaline also by 2.5 mg/kg prazosin (alpha 1-antagonist) injected at the beginning of the infusion, but not by 6 mg/kg yohimbine (alpha 2-antagonist) injected every 60 min during 4-h infusion. In addition, increased rT3 excretion was found during the infusion of alpha 1-agonist methoxamine (1.5 mg/kg/4 h), while no such effect of the infusion of alpha 2-agonist azepexol (10 mg/kg/4 h) was observed. It may be suggested that the effect of adrenaline was mediated predominantly by alpha 1-adrenoceptors and that the observed changes in biliary excretion of T3 and rT3 were related to the inhibition of 5'-monodeiodination in the liver.

Animals↗
PubMedDate not supplied

Prostaglandins during haemodialysis treatment.

The prostaglandins 6-keto Pgf1 alpha,PG F2 alpha and thromboxane B2 before and during haemodialysis were studied by means of radioisotope method. A significant increase of 6-keto PGF1 alpha and decrease of PGF2 alpha was found. The concentration of thromboxane B2 was markedly, but not significantly decreased. This constellation inhibiting the thrombocytes aggregation and promoting vasodilation seems to be favourable as far as biocompatibility is concerned. Dialysis treatment caused no significant changes in prostaglandins concentration.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Plasma levels of the anti-HIV drug 3'-azido-2',3'-dideoxythymidine (AZT): determination by RIA and HPLC.

The radioimmunoassay (RIA) with two commercial kits and the high pressure liquid chromatography (HPLC) method were employed to test human and dog blood plasma levels of AZT following oral and intravenous administration of AZT preparations Retrovir and Azitidin. A comparison of results obtained by the two RIA kits showed a good correlation. A weaker correlation was established in comparing the results obtained by RIA with those obtained by HPLC. Because of its reliability, rapid availability of results and the price, RIA is more advantageous than HPLC for routine use in monitoring the therapy as well as in determining pharmacokinetic parameters of AZT.

Administration, Oral↗