bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression and stimulation of TSH and thyroid hormones in bulls during starvation and refeeding
Authors: Tveit Borghild , Larsen Flemming 
Published: December 2008

Abstract. Sixteen bull calves were fasted during two periods, 3½ and 7 months old. Blood samples were taken every 6 h during an experimental period of 9 days: 2 control days, 5 fasting days and 2 refeeding days.
During the control days with ad libitum feeding, T3, T4 and TSH increased during the day. During the fasting period, T4 decreased with a half-life of 3.5 days and T3 with a half-life of 3 days. TSH decreased in a less regularly way to a mean of 60% of control mean. Six h after refeeding, TSH had increased to 300% of control mean. T3 and T4 had a maximum 12 h after refeeding.
As the T4 decreased with a rate nearly similar to the T4 disappearance rate in starving bulls, the secretion of T4 from the thyroid gland must have been almost stopped during the starvation period.
The morning values were below normal for all three hormones after 2 days of refeeding.
Thyroglobulin-rich colloid goitres: a result of the combined action of lithium and methimazole on the rat thyroid
Authors: Miloni E. , Bürgi H. , Studer H. , Siebenhüner L. , Lemarchand-Béraud Th. 
Published: December 2008

Abstract. Naturally occurring euthyroid goitres in man and goitres produced in experimental animals by iodine deficiency or goitrogen feeding both have in common a thyroglobulin of low iodine content. The latter experimental goitres are always depleted of colloid and thyroglobulin. In contrast, natural goitres often contain excessive amounts of colloid which may accumulate because of endocytosis becoming refractory to TSH. We tested the hypothesis that minute doses of goitrogens could lower the iodine content of thyroglobulin without colloid depletion. We then examined whether such a low-dose 'classical' goitrogen could induce excessive colloid storage rather than depletion if acting in concert with lithium, a cation which blocks endocytosis.
Rats on an adequate iodine intake were fed minimal doses of methimazole either alone or combined with lithium chloride. Chronic minimal-dose methimazole treatment lowered the iodine content of thyroglobulin without changing thyroglobulin content and thyroid weight. In contrast, addition of lithium to methimazole, produced goitres containing supranormal amounts of poorly iodinated thyroglobulin. We conclude that borderline doses of goitrogens can lower iodination of thyroglobulin without causing hyperplasia and colloid depletion. Thyroglobulin-rich goitres can be obtained by adding a second goitrogen which inhibits endocytosis. As an alternative to Marine's hypothesis of colloid goitre formation we suggest that inhibition of endocytosis, e g by goitrogens of the lithium type, could cause colloid and thyroglobulin accumulation in human iodine deficiency goitre.
Effect of a hypoglycaemic sulphonylurea (HB419) and a non-metabolizable amino acid (BCH) on the insulin release and endogenous substrate metabolism of rat pancreatic islets
Authors: Khatim Mohamed S. , Gumaa Khalid A. , Hallberg Anders , Eriksson Ulf , Hellerström Claes 
Published: December 2008

Abstract. The effects of the hypoglycaemic sulphonylurea glibenclamide (HB419) and the non-metabolizable leucine analogue β-2-aminobicyclo(2.2.1)heptane-2-carboxylic acid (BCH) on insulin release and endogenous substrate metabolism were studied in isolated rat islets. Pre-labelling of the endogenous islet substrates was performed with [14C]glucose (20 mm) or [14C]glutamine (10 mm) during a 24 h tissue culture period before measurements of insulin release or 14CO2 production in short-term incubations. Both HB419 and BCH stimulated the insulin release of the cultured islets, although BCH only after culture of islets with glutamine. The rate of labelling of the islets with [14C]glucose reached an apparent plateau after 16 h in culture and the total islet accumulation of glucose carbon over the 24 h period averaged 12.9 ± 3.0 nmol/25 islets. Less than 0.5% of the glucose residues was converted to glycogen whereas lipids represented about 2.5%. Fractionation of lipids showed 67% phospholipids, 18% triacylglycerols, 11% diacylglycerols and 6% non-esterefied fatty acid. The islet accumulation of glutamine during 24 h corresponded to 11.5 ± 1.5 nmol/25 islets.
After pre-labelling of islets with [14C]glucose there was no effect on the 14CO2-evolution over a 30 min incubation period of either HB419 or BCH. There was also no effect of HB419 after pre-labelling with [14C]glutamine, whereas, in this latter situation, a significant stimulation was observed with BCH. It is concluded that the effects on the pancreatic B-cells by antidiabetic sulphonylureas are not mediated via nutrient receptors.
Blood flow in the ovary and adjacent structures of the non-pregnant sheep
Authors: Janson P. O. , Williams D. , Petrucco O. M. , Amato F. , Seamark R. F. , Findlay J. K. 
Published: December 2008

Abstract. Blood flow to the ovary, vascular pedicle and oviduct was measured in anaesthetized non-cycling and cycling ewes by timed collection of ovarian venous blood. The degree of arterio-venous shunting across the ovary and pedicle was estimated both in vivo and in vitro by perfusing the tissues with 15 ± 5 μm radioactive microspheres.
The mean ovarian blood flow in non-cycling animals was 1.9 ml/min, which was 51% of blood flow in the ovarian vein. In cycling animals ovarian blood flow at midcycle was 2.9 ml/min (66% of ovarian venous flow) in non-luteal ovaries and 4.3 ml/min (79% of venous flow) in luteal ovaries. The degree of arterio-venous shunting was low in all stages of the cycle (1.0–2.6% across ovary + pedicle). The degree of shunting was also found to be very small in vitro (0.007–1.38%) in both non-luteal and luteal ovaries. A considerable number of microspheres was entrapped in the vascular pedicle of the ovary indicating the presence of an extensive capillary bed. There was an inverse relationship between blood flow in the ovary and flow in the vascular pedicle.
Alterations in distribution of blood flow between the ovary and adjacent structures supplied by the ovarian artery may be of functional significance in allowing rapid changes in ovarian blood flow. The results of the present study indicate that changes in ovarian blood flow during the oestrous cycle are not caused by an action on arteriovenous shunt vessels.
Effect of starvation on gonadotrophin secretion and on in vitro release of LRH from the isolated median eminence of the male rat
Authors: Warnhoff Michael , Dorsch Gunter , Pirke Karl M. 
Published: December 2008

Abstract. A perfusion system was developed in which isolated median eminences (ME) were stimulated in vitro by depolarizing agents such as potassium and veratridine. Potassium concentrations between 30 and 80 mm released increasing amounts of luteinizing hormone-releasing hormone (LRH) from the MEs of starved and control rats. Veratridine at a concentration of 50 μm caused a more prolonged LRH release in both starved and control animals. LRH secretion in vitro was slightly, though not under all conditions, significantly greater in rats starved for 5 days.
The testosterone (T)-LH feedback was studied by castrating the animals and substituting various doses of T through implantation of T-releasing capsules of different sizes. The concentration in plasma, which can prevent the castration-induced much smaller in starved than in control rats. The in vitro release of LRH evoked by 80 mm potassium was not different for starved and fed rats under various feedback conditions. Both groups revealed decreased in vitro release of LRH when castrated animals were not substituted with T.
The effect of castration was studied from 1 to 28 days. The plasma LH values rapidly increased in starved and control animals, indicating that the hypothalamic responsestration is not delayed by starvation. The release in vitro of LRH decreased from the first to the fifth day and remained constant thereafter. No significant difference between starved and fed rats was observed. The experiments indicate that the 'releasable pool' of LRH in vitro is greater under conditions of reduced LH release in vivo. The basic mechanism of depolarization-induced exocytosis of LRH from the ME is intact in starved animals.
Lack of effect of chronic hypocalcaemia on serum prolactin response to chlorpromazine
Authors: Usman Aydan 
Published: December 2008

Abstract. The effects of chronic hypocalcaemia on serum basal and chlorpromazine-stimulated prolactin (Prl) levels were studied in 16 patients with idiopathic or secondary hypoparathyroidism. These results were compared with the results of other chlorpromazine stimulation tests which were made in the normocalcaemic state after treatment with vitamin D, and in normal subjects.
In hypocalcaemic and normocalcaemic states (mean serum Ca 5.8 ± 0.24 mg/dl and 9.5 ± 0.11 mg/dl, respectively) basal Prl levels were within the normal range and during stimulation the maximal stimilated levels in each state were not significantly different from each other. Also, the mean serum Prl levels obtained from a control group were not different from values in the normocalcaemic state.
It is concluded that chronic hypocalcaemia does not inhibit Prl secretion and low serum parathyroid hormone levels do not affect basal and chlorpromazine-stimulated Prl secretion.
Dynorphin (1–13) effects on thyrotrophin-releasing hormone and thyrotrophin secretion in rats
Authors: Mitsuma Terunori , Nogimori Tsuyoshi 
Published: December 2008

Abstract. The effects of dynorphin (1-13) on thyrotrophin-releasing hormone (TRH) and thyrotrophin (TSH) secretion in rats were studied. Dynorphin (500 μg/kg) was injected iv, and the rats were serially decapitated. TRH and TSH, thyroxine (T4) and 3,3',5-triiodothyronine (T3) were measured by radioimmunoassay.
The hypothalamic immunoreactive TRH did not change significantly after dynorphin injection. Basal plasma TSH levels significantly decreased in a dose-related manner with a nadir at 40 min after dynorphin injection. The effect of dynorphin on TSH release was partially prevented by naloxone. The plasma TSH response to cold was significantly inhibited by dynorphin. The plasma TSH response to TRH did not differ from that of the control. In the l-DOPA or 5-hydrotryptophan-pretreated group, the inhibitory effect of dynorphin on TSH release was prevented, but not in the haloperidolor para-chlorophenylalanine-pretreated group. These drugs alone did not affect plasma TSH levels. The plasma T4 and T3 levels did not change significantly after dynorphin injection.
The findings suggest that dynorphin acts on the hypothalamus by inhibiting TRH release, which may be modified by amines of the central nervous system.
Comparison of LH stimulated testosterone release from Mongolian gerbil and mouse whole testes and isolated interstitial cells in vitro: difference in response and sensitivity
Authors: Probst Bodo 
Published: December 2008

Abstract. The in vitro steroidogenic response of gerbil and mouse whole testes and isolated testicular interstitial cells to stimulation with gonadotrophic hormones was compared. The testosterone release during incubation in vitro with LH/FSH was measured radioimmunologically. In whole testes incubation, basal testosterone release after 4 h was significantly lower in gerbil as compared to mouse testes, but the testosterone release on maximal LH-stimulation was not significantly different. The increment in the testosterone production from basal to stimulated levels was greater in gerbil, the production per gram testis was greater in mouse testes.
Mechanically dispersed interstitial cell preparations from gerbil and mouse released comparable amounts of testosterone during in vitro incubation. The lowest effective standard-concentration was 1.1 μIU LH/vial in gerbil and 35.9 μIU LH/vial in mouse interstitial cell incubations. Half-maximum testosterone release (ED50) occurred at 8–15 μU LH/vial for gerbil and 86–200 μIU LH/vial (ranges) for mouse interstitial cells.
The difference in sensitivity to LH stimulation of gerbil and mouse interstitial cells is approximately 13-fold, allowing the application of the gerbil interstitial cell assay to studies dealing with very small samples or little bioactive LH-concentrations.
Heterologous radioimmunoassays for monkey gonadotrophins.
Authors: Khan Shafiq A. , Diczfalusy Egon 
Published: December 2008

Abstract. The reliability of the reagents used in heterologous immunoassay procedures for FSH in monkey sera was assessed. Re-investigation of the iodination and purification of the human FSH tracer confirmed the presence of different iodinated molecular species, such as a high molecular weight aggregated material, 'intact' human FSH and subunits. Tracers obtained with the chloramine T procedure were somewhat superior to those obtained by the lactoperoxidase method.
Purification by cellulose adsorption chromatography resulted in partial dissociation of the intact hormone into free subunits, while Sephadex G-25 chromatography did not yield any subunit-like material. Purification by Ultrogel AcA 54 gave the best separation of the 'intact' iodinated FSH.
Binding studies indicated that an anti-ovine FSH (oFSH) serum showed a high degree of binding to 'intact' hFSH, although its binding to subunits and to aggregated material was also significant. The highest degree of binding to this antiserum was shown by the 'intact' tracer iodinated with chloramine T and purified sequentially by Sephadex G-25 and Ultrogel (AcA 54) chromatography.
Using a highly purified hFSH tracer in combination with three antisera (anti-oFSH, H 31; anti-hFSH, WHO, M-93-2; anti-hFSH, NIH, batch No. 5) displacement curves were investigated with three purified monkey FSH preparations. No displacement was observed with a widely available anti-hFSH (WHO, M 93-2) serum. However, linear dose dependent displacement was found with another anti-hFSH (NIH, batch No. 5) serum and with an anti-oFSH (H 31) serum. Comparison of immunoassays with the human and ovine antiserum revealed significant differences in slope, parallelism, precision and effective range. Significant discrepancies in the FSH potency estimates in monkey sera were also observed with the two assay systems. It is suggested that – until a homologous system is developed – the immunoassay employing an hFSH tracer and an anti-oFSH serum should be used for macaque FSH.
Concentration of plasma thyroglobulin and urinary excretion of iodinated material in the diagnosis of thyroid disorders in congenital hypothyroidism
Authors: Gons M. H. , Kok J. H. , Tegelaers W. H. H. , de Vijlder J. J. M. 
Published: December 2008

Abstract. In this paper we describe methods for the early aetiological diagnosis of congenital hypothyroidism, using beside the classical T4, T3 and TSH plasma concentrations, four additional parameters in plasma and urine. The first one is thyroglobulin (Tg). In normal children of more than one year of age and in adults, 5–35 ng/ml plasma is found, in neonates 2–3 weeks old, this level is 10–250 ng/ml. In patients with a stimulated thyroid gland, as in primary congenital hypothyroidism, plasma Tg levels increase. High Tg values are found in iodine deficiency and in organification defects. In the absence of the thyroid gland plasma Tg is undetectable. Low to normal levels are found in cases with hypoplasia of the gland. In patients with a disturbed synthesis of Tg, resulting in Tg deficiency of the gland, plasma Tg levels vary from undetectable to normal. The PBI-T4 plasma difference, which is caused by circulating abnormal iodoproteins is the second parameter. The products of thyroidal breakdown processes of the abnormal iodoproteins are excreted in the urine and used as the third parameter. We found that the excretion of this low molecular weight iodinated material (LOMWIOM) was increased only in Tg-deficient patients.
If the neonate is found to be hypothyroid, thyroid hormone substitution must be given immediately. Blood and urine sampling can be done just before or even directly after starting the therapy. The measurements extended with the determination of the total iodine excretion (fourth parameter) can be carried out within 1 week. With these additional methods it appeared to be possible to distinguish between several types of congenital hypothyroidism in neonates found by screening.
Increased growth rate following transfer to daily sc administration from three weekly im injections of hGH in growth hormone deficient children
Authors: Kastrup K. W. , Christiansen J. Sandahl , Andersen J. Koch , Ørskov H. 
Published: December 2008

Abstract. The effect of more frequent (daily) injections of human growth hormone (hGH) on growth rate was studied in 16 growth hormone deficient children (12 boys, 4 girls) during 2 years. All had previously been treated with im injection of hGH 2–3 times weekly and in the majority of the patients a waning growth response was observed.
For a total weekly dose of 12 IU hGH a daily dose of 2 IU was injected sc at night before sleep. This dosage has been shown by us to imitate the average nocturnal hGH profile in plasma.
Growth response on the im treatment was 5.2 ± 1.2 cm/year (sd) in boys and 5.4 ± 0.9 cm/year in girls. A significant increase was seen during the first year of sc treatment to 7.9 ± 2.7 cm in boys and 6.3 ± 2cm in girls. During the second year the growth response was still significantly increased in boys (7.2 ± 1.9 cm). Bone age was more advanced and the period of previous im treatment was longer in girls (6.7 vs 3.6 years) which may be the main cause of the waning second year response (4.7 ±1.3 cm/year). Pubertal development occurred in 9 children during treatment. However, the highest growth rates were not found in these children.
Absence of antibodies against hGH and local reactions at the injection site is evidence of the safety of the treatment, which was very well accepted by the children.
Daily sc injections thus represent an effective alternative to conventional im injections ensuring high acceptance in children with growth hormone deficiency.
Serum propylthiouracil concentration in patients with Graves' disease with various clinical course
Authors: Sato Kanji , Mimura Hisako , Kato Shuichi , Isozaki Osamu , Tsushima Toshio , Shizume Kazuo 
Published: December 2008

Abstract. The serum levels of propylthiouracil (PTU) were determined by radioimmunoassay in 10 normal subjects and in 11 patients with Graves' disease after a single 100 or 200 mg oral dose of PTU. The serum half-life of PTU in the normal subjects and in hyperthyroid patients with uneventful clinical course was 75 ± 19 min (mean ± sd, n = 6) and 73 ± 13 min (n = 7), respectively. Maximum serum PTU concentrations were usually attained within 1 h after a single 200 mg oral dose and at 1 h were 5.3 ± 1.4 μg/ml (3.1 ± 0.82 × 10−5 m) in normal subjects (n=6) and 4.8 ± 2.4 μg/ml (2.8 ± 1.4 × 10−5 m) in hyperthyroid patients (n = 7). These betweengroup differences were not significant. Serum PTU concentrations were low in a pregnant hyperthyroid patient with a weak response to PTU treatment. In another patient, who appeared resistant to PTU therapy, the serum PTU level increased as expected at testing, and it was later confirmed that, during treatment, he had not taken the drug as prescribed. In a patient who developed agranulocytosis due to methimazole and subsequently fever due to PTU, the half-life of PTU was prolonged to about 130 min.
These findings suggest that monitoring the serum PTU levels in patients with Graves' disease can be of clinical value in patients who do not respond to treatment. Furthermore, it may provide some clues as to the mechanism by which toxic reaction develops.
Endocrinological and histological changes induced by flutamide treatment on the hypothalamo-hypophyseal testicular axis of the adult male rat and their incidences on fertility
Authors: Viguier-Martinez M. C. , Hochereau de Reviers M. T. , Barenton B. , Perreau C. 
Published: December 2008

Abstract. Adult male Wistar rats were treated with flutamide from 90 to 105 days of age. In a first experiment, testis and accessory sex organs were weighed. In the same animals, hypothalamic LRH content, pituitary gonadotrophin concentrations, plasma LH, FSH, prolactin and testosterone levels, and testicular gonadotrophin receptors were evaluated. In a second experiment, fertility was tested at the end of the treatment, and histology of the testis was performed. All the results were compared to those obtained in control animals of the same age. Accessory glands of genital tract were significantly lower in flutamide-treated animals (P < 0.01). Hypothalamic LRH, pituitary and plasma FSH, and prolactin concentrations were unchanged, while pituitary and plasma LH level and especially plasma testosterone concentration were increased (P < 0.001).
Flutamide therefore exerted a strong inhibition on testosterone-dependent organs, and blocked the negative feedback of testosterone on the hypothalamo-pituitary axis, increasing the LH levels. Testis weight, intertubular tissue volume, total number and total volume of Leydig cells/testis, as well as total length and diameter of seminiferous tubules were unchanged in flutamide treated rats. However number of LH receptors/Leydig cell, nuclear area of Sertoli cells, number of FSH receptors/Sertoli cell, number of leptotene spermatocytes and of round spermatids per cross section, and yield of spermatogonial divisions were decreased after treatment. Flutamide treatment also decreased fertility by 48% (P < 0.05). This lowered fertility is likely the result of impaired spermatogenesis and/or a dysfunction of accessory sex organs.
The effects of hypothalamic extracts and TRH on the growth and hormone production of GH3 cells in culture
Authors: Yajima Yukiko , Saito Toshikazu 
Published: December 2008

Abstract. Hypothalamic factors were tested for their effects on the production of hormones and the growth of GH3 cells, cloned rat pituitary cells producing prolactin (Prl) and growth hormone (GH). Hypothalamic extracts (HE) (0.05 mg/ml) and TRH (0.3 μm) stimulated the synthesis of Prl to levels of 306% and 360%, respectively, of the control culture in a medium containing 0.5% foetal bovine serum (FBS) during a 24 h incubation. They did not affect the rate of GH production. The thymidine uptake was suppressed to 57% and 46% of the control by the addition of HE and TRH, respectively. They also inhibited the growth of GH3 to 70% and 74% of the control culture during an 8-day incubation period. On the other hand, LRH affected neither the rate of hormone production nor the thymidine uptake. Somatostatin suppressed the synthesis of Prl and GH, but it did not affect the incorporation of thymidine into the cells.
The gel filtration studies of HE revealed that the inhibitory effects of HE on the thymidine uptake were dependent on two substances, TRH and an unknown factor(s) of high molecular nature. The relationship between hormone synthesis and DNA synthesis will be discussed on the basis of the TRH-induced effects on Prl production and DNA synthesis in GH3 cells.
Age- and sex-related differences of serum thyroxine binding globulin (TBG) in healthy subjects
Authors: Kojima Noriko , Sakata Shigeki , Nakamura Shigenori , Kamikubo Keita , Okuyama Makio , Miura Kiyoshi 
Published: December 2008

Abstract. Serum concentrations of thyroxine binding globulin (TBG) were measured in healthy adult subjects aged 20–79 years (152 males and 148 females) by radioimmunoassay.
In contrast to previous reports, there were no significant age-related differences in either sex. Significant sexrelated differences were observed only in the fourth decade, being higher in females than males (P < 0.01).