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V Strbák

Publications and source records attributed to V Strbák.

At least 19 recordsLinked to original sources
PubMed1991

[The effect of 1-p-bromphenyl-5-mercapto-1,2,3,4-tetrazole (Br FMT) on thyroid gland function in rats].

The effects of the novel potential thyrostatic agent 1-p-bromphenyl-5- mercapto-1,2,3,4-tetrazole (Br-FMT) on the serum levels of thyroxine, thyrotropic hormone (TSH), the content of cyclic adenosine monophosphate (cAMP) in the thyroid gland, the body weight and the weight of the thyroid gland in liver transaminases and the white blood picture in Wistar strain rats were investigated. The effect of Br-FMT was compared with the effect of the well-known thyrostatic agent and goitrogen ethylester of 3-methyl-2-thio-4-imidazoline-1- carboxylic acid, carbimazole (Spofa) and with the control group, which received placebo only. The drugs tested were administered to animals in the dose do 7.5 mumol/animal via a gastric tube for the period of one month. Br-FMT and carbimazole decreased the level of serum thyroxine in a statistically significant manner. The serum level of TSH was evidently decreased after Br-FMT; it was not changed after administration of carbimazole in the given dose. The content of cAMP in the thyroid gland was significantly increased only after carbimazole. The weight of the thyroid gland was not significantly changed in any group under study, though after carbimazole the mean value was higher by a quarter as compared with the control group. The body weight and white blood picture were not significantly changed in all groups under study. ALT and AST values were evidently lower after carbimazole and Br-FMT, most probably due to the hypothyroid state of the animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Two novel thioamide analogues of TRH with selective activity on CNS.

TRH analogues containing C-terminal tioamide group and norvaline ([Nva2, Prot3] TRH) or norleucine ([Nle2, Prot3] TRH) in position 2 were synthesized and tested for hormonal and central nervous system (CNS) activities. Receptor binding studies revealed that the analogues neither bind to pituitary nor to brain TRH receptors. Accordingly, no TSH releasing activity was recorded. However, both analogues significantly affected sleeping time and breathing frequency. Dissociation of endocrine effects from those on the CNS of [Prot3] TRH was achieved with the replacement of histidine2 by aliphatic amino acids. The presence of central histidine is not essential for the analogues to be active on the CNS.

Amino Acid Sequence↗
PubMed1991

Thyroliberin (TRH) and TRH free acid (TRH-OH) present in milk do not originate from local synthesis in mammary gland.

UNLABELLED: Hypothalamic hormones represent a peculiar group of hormones present in milk in surprisingly high concentrations. High levels of these neuropeptides raised the question of their origin. The hypothesis suggesting local synthesis of TRH in the mammary gland was, therefore, tested. Acid extracts of human milk contained TRH and TRH-OH immunoreactivity. RIA determinations at various purification steps revealed that only a part of the immunoreactivity may represent authentic peptides. No high molecular weight TRH precursor could be demonstrated upon a sequential enzymatic treatment of human milk and rat mammary gland extracts. Exploration of rat mammary gland tissue for TRH mRNA showed that the TRH gene is not expressed in the mammary gland. Rat mammary gland homogenates were able to deamidate exogenous TRH to TRH-OH. CONCLUSION: TRH is not synthesized in the mammary gland via a high molecular weight precursor. It is likely that the TRH-free acid in milk (demonstrated for the first time in this product) originates from TRH deamidation in mammary gland cells during TRH transport from the blood.

Breast↗
PubMed1991

Late effects of breast-feeding and early weaning: seven-year prospective study in children.

The effect of breast feeding on some clinical and thyroid function parameters was studied in a prospective longitudinal study from birth up to 7 years of age. At the ages 1-7 years, the obesity rates observed in children breast-fed for less than 3 months were substantially higher than in children who had been breast-fed over longer intervals. Mean age when obesity was reported was similar in all groups (4-5 years). The rates of respiratory tract diseases were found to be highest in children which had been breast-fed for less than 2 weeks. Breast-feeding for more than 6 months had a protective effect against diseases of the gastrointestinal tract. The longitudinal follow-up revealed biphasic changes of thyroid hormones and TSH in sera with a nadir at 2-3 years, followed by an increase at the end of preschool age. Duration of breast-feeding did not affect profoundly these parameters at the ages 1-7 years. Surprisingly, during late preschool age (5-6 years) total serum cholesterol increased with the age at weaning. The atherogenic index in 6-year-old children was most favourable in the group breast-fed over more than 1 but less than 3 months. This was due to the highest levels of HDL-cholesterol in this group. We conclude that the age at weaning may be important for the later development of children.

Body Weight↗
PubMed1989

Thyrotropin releasing hormone in the pancreas of newborn rats from streptozotocin-treated mothers.

The effect of maternal diabetes (induced by i.p. injections of 40-50 mg/kg BW Streptozotocin on the day of mating) on TRH in the pancreas of newborn rats was studied. Determination of peptide alpha amidation activity and TRH precursor level on the day of birth revealed decreased biosynthesis of TRH resulting in profoundly (10 times) lower pancreatic TRH and TRH-OH concentrations in pups of diabetic rats. Pancreatic His-Pro-diketopiperazine (His-Pro-DKP) remained unaffected by maternal diabetes. The depression of pancreatic TRH was less profound 24 h later, and even elevated TRH was measured in the pancreas of pups of diabetic mothers on postnatal day 5. Short term postnatal starvation or nursing of intact pups by the diabetic foster mother did not affect pancreatic TRH. It could be postulated that postnatal TRH development in the rat pancreas is retarded by maternal diabetes, while His-Pro-DKP remains unaltered.

Aging↗
PubMed1989

[Comparison of the results of radioimmunologic and hemagglutination methods in the determination of antibodies against thyroglobulin and the effect of these antibodies on thyroglobulin serum levels].

The following methods have been introduced at our institute: labeling of human thyroglobulin (H-Tg) with the radioiodine 125I by the lactoperoxidase method, radioimmunologic method for serum H-Tg determination by means of rabbit antiserum to H-Tg prepared at our institute, and radioimmunologic method for the determination of antibodies to thyroglobulin. Sera from 15 patients with different thyropathies were examined by the given methods. In the first part of the work the quality of 125I labeled H-Tg was studied. The maximum binding by antiserum was found to be substantially decreased as early as two weeks following labeling, The second part of the study presents our first experience with comparing our RIA method and the hemagglutination method for TgAb determination. The results yielded by the two methods did not differ significantly. The level of serum H-Tg is falsely affected by the competition of TgAb autoantibodies with the first rabbit antibody to H-Tg at recipitation by means of the second antibody. It is therefore important to establish the titer of autoantibodies before actual serum H-Tg determination. This approach is of importance e.g. in following up patients with malignant goiter. The introduced methods are a contribution to diagnosis and management of patients with thyropathies.

Autoantibodies↗
PubMed1989

Incidence of thyroid hormone autoantibodies in patients with thyroid diseases with respect to diagnosis, other types of autoantibodies, duration of disease and treatment.

Thyroid hormone autoantibodies (THAA] were estimated in a total of 149 patients (139 women and 10 men) with various thyroid diseases. THAA were found in a total of 22 patients (all women), i.e. 14.7%. In 8 of them both T4Ab and T3Ab were found, while T4Ab only were found in 4 patients and T3Ab only in 10 patients. The highest incidence of THAA was found in patients with diffuse lymphocytic thyroiditis (i.e. 11 cases out of a total of 64 patients) and similarly high incidence was in patients with suspected autoimmune goiter but without thin needle biopsy (i.e. 5 cases out of a total of 21 patients). If only the patients with manifested or silent hypothyroidism were selected, T4Ab were found exclusively in this group, while the incidence of T3Ab was 3 times higher as that in patients without hypothyroidism. Though the incidence of T4Ab in patients with positive antithyroglobulin and antimicrosomal antibodies was 3 times higher than in negative ones, the difference was not significant. No correlation was found between the incidence of THAA on one hand and the duration of disease, the duration of treatment and the drug used for treatment on the other. However, a significant correlation was found between the incidence of THAA and the presence of goiter (P less than 0.05).

Autoantibodies↗
PubMed1988

Thyroid hormone levels in cow maternal and fetal sera during last trimester of pregnancy.

Thyroid hormone levels were studied in 51 paired pregnant cow and fetal calf serum samples (fetal age 7-9 months). Thyroxine and rT3 levels were substantially higher and those of T3 distinctly lower in calf fetuses as compared to respective mothers. An increase of T3 has been detected in calf sera at the fetal age 8 to 8.5 months. These results suggest some prenatal maturation of thyroxine metabolism in the calf.

Animals↗
PubMed1987

Effects of sauna and glucose intake on TSH and thyroid hormone levels in plasma of euthyroid subjects.

The effect of sauna on thyroid function parameters and its modification by glucose was studied in young euthyroid male volunteers. A 30-minute stay in sauna resulted in an increase in plasma TSH; the response was exaggerated if glycemia had been increased by oral glucose intake at the beginning of the experiment. Plasma rT3 also increased in sauna, this response was, however, blunted by the higher glycemia. TSH response to sauna was definitely present in young men (aged 20 to 25) and absent in middle-aged ones (50 to 55). To explore the mechanism of the effect of increased glycemia, TRH tests were performed and dopamine infusions were administered with and without glucose pretreatment. Increased glycemia did not affect TSH and T3 response to TRH in young volunteers; however, 90 minutes after the administration, plasma rT3 levels were significantly lower in glucose pretreated subjects than in those receiving TRH injections after water pretreatment. Simultaneous infusion of glucose prevented the inhibitory effect of dopamine infusion on plasma TSH. It was concluded that glucose directly modulates the effect of sauna on plasma TSH at a suprapituitary level, while the inhibiting effect of glucose on plasma rT3 response to sauna and TRH is probably mediated by the insulin effect on thyroid hormone metabolism.

Adult↗
PubMed1987

Biological activity of TRH thionalogue and its diastereoisomers.

Binding affinity and TSH-releasing activity of [Prot3] TRH analogue (L-pyroglutamyl-L-histidyl-L-proline thioamide), TRH and their LDL and LLD diastereoisomers were compared in rats. Binding affinity and dose-related increase of TSH secretion were similar for both [Prot3] TRH and TRH. Moreover, similar effect of both peptides on sleeping time and motoric activity of rat was found. Substitution of L- for D-amino acids of TRH and [Prot3] TRH decreased the binding affinity and TSH-releasing activity as well. It was concluded that [Prot3] TRH analogue is as active as native TRH.

Animals↗
PubMed1987

[Leprechaunism].

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Abnormalities, Multiple↗
PubMed1987

Exchange transfusion in premature newborns: effect of maturity on thyrotropin and thyroxine responses.

The effects of exchange transfusion on plasma T4 and TSH were studied in two groups of premature newborns to evaluate the effect of maturation on the reactivity of the pituitary-thyroid axis. In newborns with a birth weight between 1900-2500 g (gestational age 35.4 +/- 0.45 weeks) the responses of both hormones were essentially similar to those reported previously for mature newborns (a profound decrease during the procedure and an increase 24 h later). In a group of newborns with a birth weight below 1900 g (average 1673 +/- 55, gestational age 32.7 +/- 0.72 weeks), however, the secondary increase in plasma T4 at 24 h after the procedure was absent. At this time both T4 and TSH levels were significantly lower than in those in heavier newborns. It is concluded that the ability to respond to exchange transfusion by an increase in plasma thyroxine at 24 h after the procedure matures at the gestational age between 32 and 35 weeks.

Exchange Transfusion, Whole Blood↗
PubMed1986

Role of thyrotropin-releasing hormone in thyroid-stimulating hormone and growth hormone regulation during postnatal maturation in female Wistar rats.

The role of endogenous thyrotropin-releasing hormone (TRH) in the control of pituitary thyroid-stimulating hormone (TSH) and growth hormone (GH) secretion was studied during postnatal maturation in female Wistar rats. Half of the sucklings in each litter was treated intraperitoneally with either specific rabbit antiserum against TRH or normal rabbit serum (0.1-0.3 ml according to age). All animals were decapitated after 2 h. The presence of anti-TRH activity was checked as a binding of labelled TRH with plasma of the experimental animals. Immunoneutralization of endogenous TRH resulted in a decrease of plasma TSH in 3- to 15-day-old female pups as compared to control littermates. No effect of TRH antibody injection was seen at the ages of 1, 21, 30 and 70 days despite the presence of excess antibody in the plasma. A profound effect of TRH antibody on plasma TSH was seen again at the age of 100 days. Plasma GH in the same animals exhibited a paradoxical increase after TRH immunoneutralization at the age of 5 and 8 days, a decrease was found at the age of 21 days. It was concluded that hypothalamic TRH control of TSH secretion matures early in Wistar rats. Hypothalamic secretion of TRH at the ages of 1, 21, 30, and 70 days is low and(or) its role in TSH regulation is masked by other regulating factors. TRH may play a dual role in the regulation of GH secretion during the postnatal period.

Aging↗
PubMed1986

Human milk does not degrade TRH.

We have found previously that TRH is accumulated in rat milk in biologically active form. TRH was reported to be present in high concentrations in human milk too. These findings together with the absence of TRH degrading activity in plasma of newborns suggest a possible physiological role of the neurohormone coming from milk. We studied, therefore, TRH degrading activity of human milk. TRH incubated in vitro with 100 microliters human milk (4 days and 4 months after delivery) in 0.01 mol l-1 phosphate saline buffer (pH 7.6) with 1% gelatine (total volume 0.3 ml) at 37 degrees C was not degraded during 2 hours as revealed by specific RIA. The addition of the same amount of milk to adult human plasma did not affect intensive TRH degradation. We conclude that human milk does not contain TRH degrading enzymes nor their inhibitors.

Humans↗
PubMed1986

Effect of breast-feeding on infant thyroid activity: 3 year follow up--longitudinal study.

The effect of breast-feeding on serum thyroid hormones and TSH was studied in a longitudinal study from birth up to 3 years. T4 was found to be significantly higher in breast-fed than in weaned infants at the age of 4 and 6 months and so was rT3 at the age 4 months. The body weight of breast-fed girls at the age 4 and 6 months was lower than that of formula-fed ones. Breast-feeding at the age 9 months resulted in a decreased serum TSH. Serum T3 of infants weaned before the end of the first week of life was higher than in other groups of infants at the age of 10 weeks. Serum T4 of children 1-2-year-old correlated positively with the age at weaning, provided that they had been breast-fed at least for 60 days. Serum rT3 of 2-year-old children also correlated with the age of weaning. Serum TSH at the age of 3 years was higher in children who had been weaned during first 60 days of life than in those weaned later. It is concluded that breast-feeding possess some immediate effects on thyroid function parameters. Some effects were still detected at the age of 1-3 years.

Age Factors↗