bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iodine metabolism and the effect of TSH in thyroid glands of early bovine embryos
Authors: Avivi A. , Shemesh M. , Lindner H. R. 
Published: December 2008

Abstract.
The ontogeny of the thyrotrophin-thyroid axis during the first trimester was studied in 104 bovine embryonic thyroids taken from foetuses of crown-rump length 1.4 to 19.2 cm (25–120 days). The uptake of labelled iodine in vitro in the absence or presence of TSH was measured. The per cent incorporation of radioiodine into iodotyrosines and iodothyronines in the presence and absence of TSH was also studied. It was found that the foetal tissue displayed radioiodine uptake by 25 days of foetal life and the uptake increased with age. TSH caused a further increase in radioiodine uptake in foetuses of 40 days or older. Incorporation of radioiodine into MIT and DIT was apparent at 25 days and into T3 and T4 by 40 days of foetal life. Addition of TSH increased the proportion of total radioiodine found as DIT and thyroxine in foetuses of 40 days older. This TSH stimulation of radioiodine incorporation increased with age. However, the proportion of radioiodine found as MIT and T3 was not affected before 120 days of foetal life. This was in marked contrast to the adult thyroid where the proportion of radioiodine found as T3 was increased by the addition of TSH. It is concluded that the foetal thyroid can respond to TSH by at least 40 days of foetal life and that this response differs from that seen in the adult.
Forearm insulin uptake in healthy subjects after oral glucose and intravenous glipizide
Authors: Nygren Arne , Lindblad Lars Erik , Sundblad Lars 
Published: December 2008

Abstract.
In six healthy subjects fasted overnight two different experiments were carried out on separate days and in random order: A. Oral glucose followed 60 min later by iv glipizide. B. Iv glipizide followed 60 min later by oral glucose. Each experiment was divided into two 60 min periods, and the fractionated insulin uptake by forearm tissue was calculated for each 60 min period. When the fractional insulin uptake values for these four 60 min periods were compared it was found that the uptake of insulin was significantly higher for the 60 min period that was obtained in response to glucose without glipizide pre-treatment, than it was for any of the other 60 min periods. Moreover, in some of the participants the venous insulin concentration occasionally exceeded the corresponding arterial insulin concentration after iv glipizide administration. These findings imply that glipizide may decrease insulin binding to peripheral insulin receptors in healthy individuals.
Influence of lactation on oral glucose tolerance in the puerperium
Authors: Lenz Suzan , Kühl Claus , Hornnes Peter J. , Hagen Claus 
Published: December 2008

Abstract.
The influence of endogenous hyperprolactinaemia on oral glucose tolerance in normal women post-partum was studied. An oral glucose tolerance test (OGTT) was performed 8 weeks after delivery in 23 women, 13 of whom were breastfeeding. The lactating women had significantly higher plasma prolactin values before and during the OGTT than the non-lactating women (P < 0.005). Fasting values of serum FSH, LH, progesterone and plasma glucagon were similar in the two groups. The non-lactating women had higher fasting concentrations of serum oestradiol (P < 0.0005), plasma glucose (P < 0.05) and insulin (P < 0.05) than the lactating women. After oral glucose no differences were found between lactating and non-lactating women in changes in plasma glucose, insulin and glucagon concentrations. It is concluded that lactating women 8 weeks post-partum do not have an impaired OGTT compared to non-lactating women despite elevated plasma prolactin levels.
Development and regulation of the prostaglandin F2α receptor in the rat ovary
Authors: Müller Ulrich , Bauknecht Th. , Siebers Jan Willem 
Published: December 2008

Abstract.
Ovaries of adult rats specifically bind PGF2α while those of immature animals do not. Induction of luteinization by hCG in juvenile animals, however, results in specific binding of PGF2α It is suggested that luteal cells are the only cell type of the ovary, which is endowed with specific receptors for PGF2α The number of PGF2α binding sites varies during the ovarian cycle. Most free receptors are detectable in early pro-oestrus, least in the oestrus stage. The oscillation of receptors disappears after inhibition of prostaglandin synthesis by indomethacin. Therefore the apparent cyclic variation of prostaglandin receptors must be ascribed to occupancy of the receptors by varying amounts of endogenous prostaglandin F2α.
Glucose metabolism in rat hypothalamus
Authors: Lautala Pentti , Martin Julio M. 
Published: December 2008

Abstract.
In vitro glucose oxidation and glucose transport in the rat medial (MH) and lateral (LH) hypothalamic areas was measured. Glucose oxidation was calculated from the conversion of [U-14C]glucose to 14C02 and glucose transport from 14C02 produced from [114C]glucose in the presence of phenazine methosulphate and NaF. Increasing glucose in the medium from 1 him to 20 mm enhanced glucose oxidation two-fold in MH and 40% in LH. Addition of insulin, 100 (iU/ml, to the medium decreased glucose oxidation 30% both in MH and LH at both 4 mm and 20 mm glucose. Fasting did not affect glucose oxidation in either of these hypothalamic areas. Glucose transport was not affected by insulin, but was increased significantly when glucose was raised from 0.25 mm to 1.0 mm. Fasting also increased glucose transport in both hypothalamic areas. In conclusion, extracellular glucose concentration seems to be the major regulator of glucose utilization by the rat hypothalamus. Insulin, rather than increasing, seems to decrease glucose oxidation while having no effect on glucose transport.
Hypothalamic-pituitary function in uraemia
Authors: Cowden E. A. , Ratcliffe W. A. , Ratcliffe J. G. , Kennedy A. C. 
Published: December 2008

Abstract.
In a study of 221 patients with progressive uraemia and after successful renal transplantation, all patients had normal levels of plasma 11-hydroxycorticosteroids and sex hormone binding globulin (SHBG). Concentrations of T4 and Ts fell significantly (P < 0.005) with progressive uraemia whilst TSH remained normal. Levels of gonadal steroids also fell significantly (P < 0.0005) and in some patients there was gonadal failure with LH and FSH > 50 U/l; in the remainder, there was a modest increase in LH and minor increase in FSH as renal function deteriorated. Elevated Prl concentrations (P < 0.005) occurred even in moderate chronic renal failure and levels rose with progressive uraemia.
In patients on maintenance haemodialysis, TSH response to thyrotrophin releasing hormone (TRH) was significantly blunted (P < 0.01) at 20 min but showed a late rise at 60 min; basal levels of GH were elevated in 27% and there was a heterogeneous GH response to TRH; LH response to gonadotrophin releasing hormone (GnRH) was normal whilst response of FSH was significantly blunted (P < 0.01). Irrespective of basal Prl level, there was a grossly blunted Prl response to TRH and metoclopramide (MCP) and no suppression of Prl after acute administration of i.-dopa or bromocriptine.
Following successful renal transplantation, endocrine status was entirely normal.
It is concluded that gross biochemical endocrine abnormalities arise with progressive uraemia, which are not ameliorated by maintenance haemodialysis but are abolished by successful transplantation. There is evidence of both hypothalamic and pituitary dysfunction contributing to these anomalies, which may be sensitive indices of non urea and creatinine related uraemic toxicity, and whose significance requires further evaluation.
Effect of inhibin like factors on gonadotrophin release by the mouse pituitary in vitro
Authors: Ramasharma K. , Sairam M. R. , Ranganathan M. R. 
Published: December 2008

Abstract.
The release of gonadotrophins by the mouse whole pituitary in vitro was investigated. Whole tissue from 34 day old male mice was highly responsive to synthetic LRH in short incubations at 37°C. About 15% of FSH and 17% of LH were secreted during a 3 h pulse with 3 ng of LRH. Pre-exposure of the mouse pituitary to fractions containing inhibin activity, inhibited the FSH release induced by LRH. Inhibin from bovine and human seminal plasma and porcine follicular fluid preferentially inhibited FSH secretion, while LH secretion was also reduced by inhibin like factors from bovine follicular fluid and testicular extract. The inhibition of FSH and/or LH release was measured by specific radioreceptor assays and could not be due to destruction of either gonadotrophin or LRH. Purified bovine seminal plasma inhibin was effective at very low concentrations in vitro.
The whole incubation system is simple and an estimation of inhibition of bioactive (binding activity) FSH release can be obtained within 24 h.
On the role of dopamine receptors in the central regulation of human TSH
Authors: Delitala G. , Devilla L. , Canessa A. , D'Asta F. 
Published: December 2008

Abstract.
The effects of acute administration of haloperidol (4 mg im) and pimozide (4 mg orally) on TSH and Prl secretion were studied in normal and hypothyroid man. The TRH-induced TSH secretion before and after pre-medication with pimozide and domperidone, a peripheral dopamine (DA) blocker, was also evaluated in a group of normal subjects. Haloperidol and pimozide induced a marked increment in serum Prl; mean Prl levels were still significantly elevated 12 h following pimozide administration. A small but significant TSH increase was observed following haloperidol and pimozide in normal as well as hypothyroid subjects. Both domperidone and pimozide significantly enhanced TRH-induced TSH release.
In another experiment 3 women with primary thyroid failure received an infusion of DA (4 (μg/kg/min for 4 h) with and without domperidone administration. TSH and Prl levels were suppressed by DA, but the effect was completely abolished by domperidone.
The results suggest that psychotrophic drugs, such as haloperidol and pimozide, can, like substituted benzamides, stimulate TSH release in man. Since domperidone and DA do not cross the blood-brain-barrier and domperidone significantly enhanced the TSH response to TRH, the data also support the hypothesis that human TSH is regulated by DA at the hypothalamus (median eminence) and/or pituitary level.
Presence of gangliosides in the structure of membrane receptor for thyrotrophin
Authors: Gardas Andrzej , Nauman Janusz 
Published: December 2008

Abstract.
Thyroid gangliosides were isolated from bovine thyroid tissue. Neutral lipids and glycolipids were removed by chromatography on a DEAE-cellulose column and residual acidic phospholipids by alkaline degradation.
Thyroid gangliosides were separated by chromatography on a silica acid column into 9 different fractions. Thyroid gangliosides were found to be active in the inhibition of [125I]TSH binding to thyroid plasma membranes and this results from a direct action between thyrotrophin and gangliosides. The most active fraction contained gangliosides with two sialic acids per molecule. Pre-incubation of thyroid plasma membranes for 4 hours at 37°C with gangliosides and removal of the unbound gangliosides increased the [125I]TSH binding to pre-treated membranes by 10–20%.
Anti-ganglioside antibodies obtained by immunisation of rabbits inhibited [125I]TSH binding to thyroid plasma membranes by 60 to 80%. The thyroxine (T4) level in blood serum of immunized animals was significantly decreased after the first immunization and T4 become almost undetectable after the booster injection implying that antibodies against thyroid gangliosides produce severe impairment of thyroid cell function.
The effect of varying iodine content on the proteolytic activity of rat thyroid lysosomes
Authors: Santisteban Pilar , Lamas Luis 
Published: December 2008

Abstract.
The possibility that the iodine supply modulates thyroid lysosomal activity was investigated in rats receiving chronic or acute increasing doses of iodide. The lysosomal activity or the various experimental groups was determined by measuring the activity of β-glycerophosphatase and cathepsin D both in thyroid homogenates and in semipurified thyroid lysosomal preparations, and the degradation of labelled thyroglobulin by the various lysosomal fractions. In the chronic experiments β-glycerophosphatase and cathepsin D activities increased with the iodide supply of the animals up to 100 μg I/rat and decreased slightly thereafter. In the acute experiments the activity of these enzymes increased up to 1000 μg I/rat and decreased above 5000 μg I/rat. The proteolytic activity of lysosomal fractions from the various experimental groups towards thyroglobulin decreased slightly with increased iodide supply both in chronic and acute experiments.
The results suggest that thyroid lysosomal activity may participate in the autoregulation of thyroid secretion by inducting synthesis of new enzymes and modulating thyroglobulin degradation.
Insulin, glucagon and somatostatin in the perfused rat pancreas and the effects of HB 699 (4-(2-(5-chloro-2 metoxy-benzamido)-ethyl)-benzoic acid)
Authors: Efendić Suad , Enzmann Franz , Gutniak Mark , Nylén Anita , Zoltobrocki Manfred 
Published: December 2008

Abstract.
HB 699 (100 μg/ml), almost identical with the left residue of the sulphonylurea glibenclamide, enhanced basal insulin and somatostatin release from the perfused rat pancreas. The compound also augmented both the early and the late insulin release stimulated by 6.7 mm glucose, while with 16.7 and 33.3 mm glucose only late insulin release was increased. Furthermore, HB699 enhanced both phases of glucose induced somatostatin release irrespective of whether 6.7, 16.7 or 33.3 mM glucose were used. As for glucagon release, HB 699 suppressed basal and arginine stimulated glucagon secretion.
The present findings imply that the sulphonylurea moiety of glibenclamide is not a prerequisite for its stimulatory action on insulin and somatostatin release. It is suggested that the enhanced somatostatin release mediates the inhibitory effect of the compound on glucagon release.
Effect of anaesthesia on serum levels of LH and FSH in man with and without GnRH test
Authors: Bizzarro Antonio , Martino Gennaro Di , lannucci Flavio , Verdoliva Alfredo , Florio Antonino , Guarino Giuseppina , Iacono Giovanni 
Published: December 2008

Abstract.
The effect of anaesthesia with atropine and pentobarbital (PB) in three groups of volunteers has been tested. The dose used for the anaesthesia was 20 mg/kg body weight of PB. The experiment was performed with and without stimulation test with GnRH. Anaesthesia was shown to increase serum levels of LH and to increase the response to stimulation with GnRH. Atropine and mental stress seem to have no effect on the hormones. No variation in serum levels of FSH in the anaesthesized volunteers was noted. The data obtained have been statistically controlled.
Gonadotrophin releasing hormone causes a biphasic secretion of luteinizing hormone and follicle stimulating hormone by cultures of rat anterior pituitary cells
Authors: Eddie L. W. , Baker H. W. G. , Higginson R. E. , Hudson B. 
Published: December 2008

Abstract.
Primary monolayer cultures of adult male rat anterior pituitary cells secreted both LH and FSH in a biphasic manner when incubated with gonadotrophin releasing hormone (GnRH). The peaks of secretion of LH and FSH were coincident; the first occurred between 15 and 30 min and the second between 1 and 3 h after the addition of GnRH. Approximately 20% of the total amount of gonadotrophins secreted in the 6 h treatment with GnRH was contained in the first peak.
Inhibitors of the secretion of gonadotrophins affected LH and FSH secretion differently. Inhibin suppressed the secretion of FSH to a greater extent than that of LH, whereas testosterone and cycloheximide had a greater effect on LH. Neither phase of secretion of LH or FSH was reduced preferentially by inhibin or testosterone but the greater effect of cycloheximide was on the second phase of secretion.
Estimation of systolic time intervals and timing of arterial sounds in hyperthyroidism during antithyroid medication
Authors: Jerić M. , Banovac K. , Barić Lj. , Sekso M. 
Published: December 2008

Abstract.
During antithyroid drug therapy hyperthyroid patients with border-line elevated serum T3 had shortening of pre-ejection period (PEP) and QKd interval (period between the onset of QRS complex and the onset of the Korotkoff arterial sound). There was a significant relationship between PEP and QKd interval with serum T3 concentration in a group of patients under medical therapy; PEP and QKd were normalized later than serum thyroid hormone concentrations in such patients. Propranolol induced a prolongation of PEP and QKd interval in hyperthyroid patients.
PEP and QKd are sensitive measures of metabolic status in thyrotoxic patients during antithyroid treatment.
Tolbutamide, glucose, calcium, and somatostatin secretion
Authors: Hermansen Kjeld 
Published: December 2008

Abstract.
We studied the actions of tolbutamide on the release of somatostatin, insulin, and glucagon from the isolated, perfused dog pancreas. Tolbutamide (180 μm) elicited a biphasic response of all three islet hormones in the absence of glucose. In the presence of normal glucose (5.5 mm), 180 μm tolbutamide was again stimulatory, however, now the D cell response appeared uniphasic and the relative increase of somatostatin was lower than in the absence of glucose. At the highest perfusate glucose of 11 mm, no augmentation of the somatostatin output was seen to 180 μm tolbutamide, whereas the B and A cell secretion was still stimulated. In dose-response studies with tolbutamide (1.8–1800 μm) it was found that the D cell threshold to tolbutamide was 18 μm, Furthermore, that maximal D cell secretion was attained in the presence of 180 μm tolbutamide at low glucose (1.4 mm) and of 18 μm tolbutamide at normal glucose (5.5 mm), respectively. The insulin and glucagon responses showed clearcut dose-dependency over the range of tolbutamide doses applied. The B and A cell threshold to tolbutamide was 1.8 μm when the prevailing glucose level was stimulatory for the B and A cell, respectively. The finding that D and B cell responses to tolbutamide were eliminated during calcium deprivation indicates a key role of calcium in the events that proceeds to tolbutamide-mediated somatostatin and insulin release. In conclusion, the primary effect of tolbutamide on the islet cells is to stimulate hormone secretion, however, pertubations in terms of appearance and magnitude of D, B, and A cell responses depend on the balance between the concentrations of tolbutamide and glucose.
Long-term and short-term effects of calcium, verapamil and diazoxide on biosynthesis and release of (pro-)insulin in isolated islets of rat pancreas
Authors: Leinweber K. P. , Schatz H. 
Published: December 2008

Abstract.
Glucose-induced release and biosynthesis of insulin can be influenced independently during short-term incubations of isolated pancreatic islets. We studied whether such a dissociation between synthesis and release is still retained after a longer period of islet culture. Media varying in calcium concentration (0, 0.8, 2.5, 5.0 mm), verapamil (8 μm) or diazoxide (100 μg/ml) were used in short-term incubations for 2 h and during 38 h of islet culture at 2 mg/ml glucose.
In the short-term experiments, the increase in calcium concentration caused a stepwise augmentation of insulin release but a gradual decrease in (pro-)insulin synthesis; verapamil and diazoxide markedly diminished insulin secretion, whereas hormone biosynthesis was found unchanged. Culture of islets with calcium omission, verapamil or diazoxide resulted also in a reduced insulin release during the 38 h of cultivation. After culture, insulin release was not different from the controls any more. (Pro-)Insulin biosynthesis, however, was now significantly diminished in islets cultured before with verapamil and diazoxide; following culture in calcium-free medium biosynthesis was also relatively decreased compared to the values obtained in the acute short-term experiments.
It appears from these results that the pharmacological inhibitors of insulin release tested in vitro do no longer influence release and biosynthesis of insulin independently after a longer culture period, in contrast to their short-term effects.
Bioavailability of oestriol
Authors: Englund D. E. , Elamsson K. B. , Johansson E. D. B. 
Published: December 2008

Abstract.
A rapid radioimmunoassay, using a specific antiserum against oestriol (Oe3) was developed for the analyses of unconjugated oestriol in post-menopausal women before and after oral administration of oestriol. One ml plasma was extracted once with 10 ml diethyl ether and assayed without further purification. The plasma levels of oestriol in post-menopausal women appear to be below 5 pg/ml. When 10 ml plasma from a pool was assayed 2.9 pg/ml was found. When 1 ml was assayed from individual patients levels between 10–20 pg was found, which was not different from the plasma blank. A rise in plasma oestriol was found already 15 min after oral administration of 6 mg or 12 mg oestriol (Ovesterin®). On the average there was a plasma oestriol peak after 45 min and then a gradual decrease to low levels within 3 to 4 h. It is concluded that oestriol is rapidly absorbed when administered orally. However, the duration of the plasma oestriol elevation is short. Oestriol is rapidly metabolized. The short elevation probably explains the weak oestrogenic effect exerted by oestriol when administered once a day as receptor affinity for oestriol is low.
Cellular growth in several organs of normal and dwarfed Snell mice
Authors: van Buul-Offers Sylvia , Van den Brande Jan Leo , Dumoleijn L. , Feijlbrief M. , van de Klundert P. L. M. 
Published: December 2008

Abstract.
The DNA, RNA and protein content of different organs was studied in Snell dwarf mice and compared with unaffected controls at different ages. The following organs were included: liver, kidneys, heart, submandibular salivary glands, spleen and thymus. In normal mice the rapid post-natal growth of all these organs is due to cell division and in the liver, kidneys, heart and submandibular salivary glands to cell enlargement as well.
In dwarf mice weight of most organs studied is comparable with that of 1–2 weeks old normals. The data suggest no differences in cell size between dwarfs and normals in the liver, submandibular salivary glands, spleen and thymus, irrespective of age. In contrast, cell size of the heart and kidneys remains below the normal range and the RNA content is lowered as well. RNA is also low in the submandibular salivary glands and the liver, despite their normal protein content.
Cellular growth in organs of dwarf mice during treatment with growth hormone, thyroxine and plasma fractions containing somatomedin activity
Authors: van Buul-Offers Sylvia , Van den Brande Jan Leo , Dumoleijn L. , Feijlbrief M. , Hoogerbrugge C. M. , van de Klundert P. L. M. 
Published: December 2008

Abstract.
DNA, RNA and protein content of the liver, kidneys and spleen were studied in dwarf mice during treatment with human growth hormone (hGH), thyroxine and plasma fractions containing somatomedin activity (SM-P1 and SM-P4).
This investigation has revealed that part of the growth of the liver and all growth of the spleen obtained with the administered preparations, are a consequence of nuclear division. Cell enlargement is not induced in the spleen by either of the preparations used. In the liver a small degree of hypertrophy is obtained with SM-P1. In the kidney both cell number and cell size are stimulated by thyroxine and to a lesser extent by hGH and SM-P1. With regards to the RNA content per cell an increase is obtained with hGH and thyroxine in the liver and in the kidneys also with SM-P1, but not in the spleen.
These data demonstrate that semi-purified SM-preparations, like hGH and thyroxine, might be potent stimuli for the restoration of the impaired nucleic acid metabolism in these organs of the Snell dwarf mouse.