bluuebunny/crossref_metadata_2025 huggingface dataset:
The mechanism of action of tumour necrosis factor-α and interleukin 1 on FRTL-5 rat thyroid cells
Authors: Pang Xuan-Ping , Hershman Jerome M. , Smith Vierka , Pekary A. Eugene , Sugawara Masahiro
Published: June 2009

Previous work showed that treatment of rats with tumour necrosis factor-α produced a model of nonthyroid illness in which there was reduction of circulating thyroid hormones and TSH, reduced thyroid response to TSH, and reduced thyroid iodide uptake. In vitro studies showed that tumour necrosis factor-α binds to a specific receptor on FRTL-5 rat thyroid cells, that TSH increases the number of tumour necrosis factor-α receptors, and that tumour necrosis factor-α inhibits iodide uptake by these cells. In the present study, we obtained additional data on the effects of tumour necrosis factor-α on FRTL-5 cells and studied the mechanism of action of tumour necrosis factor-α in these cells. Tumour necrosis factor-α inhibited both basal and TSH-stimulated [125I]iodide uptake; tumour necrosis factor-α slowed the recovery of [125I]iodide trapping after the cells were exposed to TSH and augmented the loss of the [125I]iodide trapping function after the cells were deprived of TSH; tumour necrosis factor-α inhibited [125I]iodide trapping in a noncompetitive manner; tumour necrosis factor-α did not affect cell growth of FRTL-5 cells. Interleukin-1 (IL-1) also inhibited basal and TSH-stimulated [125I]iodide uptake, but it stimulated cell growth. Tumour necrosis factor-α and IL-1 did not affect the generation of cAMP in the presence or absence of TSH; these cytokines blocked the cAMP-induced stimulation of [125I]iodide uptake. Tumour necrosis factor-α did not affect [3H]arachidonic acid uptake or release by FRTL-5 cells. The inhibitors of the phospholipase A2-arachidonic acid pathway did not affect the action of tumour necrosis factor-α. The H2O2 scavenger, catalase, did not block the action of tumour necrosis factor-α. The results show that both tumour necrosis factor-α and IL-1 inhibit FRTL-5 function and that the site of action of these cytokines is distal to the production of cAMP. The actions of tumour necrosis factor-α on FRTL-5 cells do not appear to be mediated by the phospholipase A2-arachidonic acid pathway or by H2O2.
Epidermal growth factor in mice: Effects of estradiol, testosterone and dexamethasone
Authors: Tuomela Tiina , Miettinen Päivi , Pesonen Kristina , Viinikka Lasse , Perheentupa Jaakko
Published: June 2009

To clarify the influence of steroids on the metabolism of epidermal growth factor, we studied the effects on its concentrations in adult male and female mice of 1. gonadectomy, 2. postgonadectomy treatments with estradiol and testosterone, and 3. treatment with dexamethasone. We also measured its mRNA levels in submandibular salivary glands and kidneys after ovariectomy. After gonadectomy, the male mice had 1.4-fold higher mean epidermal growth factor concentration in the urine than the female, in contrast to a 1.5-fold reverse difference in intact mice; the female mice had 2.5-fold higher concentration in the submandibular glands than the male animals, in contrast to a 4.5-fold reverse difference in intact mice. The kidney sex difference of intact mice (male > female) was abolished. In both gonadectomized sexes, treatment with testosterone increased the concentration of epidermal growth factor in plasma and the submandibular gland; treatment with estradiol increased the concentration in urine and decreased it in the submandibular gland. Treatment with dexamethasone decreased the concentration of epidermal growth factor in plasma of the male mice, and in urine of the female mice, thus decreasing the sex differences. In the submandibular gland and the kidneys, dexamethasone increased the concentration. The mRNA levels were higher in the submandibular gland and lower in the kidneys in the ovariectomized than in the intact female mice. The effects of sex steroids on epidermal growth factor concentrations are mediated through modulation of its gene activity. Testosterone has an increasing and estradiol a decreasing effect in the submandibular gland. Estradiol has also an increasing effect in the kidneys.
Characterization of cytosolic female rat liver receptors of the lactogenic type
Authors: Emtner M. , Roos P.
Published: June 2009

Some properties of cytosolic receptors of the lactogenic type from female rat liver were studied and compared with those of membrane-bound (microsomal) receptors. The association constant between the cytosolic receptors and human growth hormone was 2.2 l/nmol, which was not significantly different from the value obtained for the microsomal receptors (3.6 l/nmol). Since unlabelled hGH and human prolactin, but not bovine growth hormone, displaced [125I]hGH bound to receptors from both sources, the cytosolic receptors, like the microsomal receptors, must be lactogenic. Furthermore, the cytosolic receptors were recognized by a monoclonal antibody raised against microsomal receptors from female rat liver. However, covalent cross-linking of cytosolic receptors to [125I]hGH and subsequent sodium dodecyl sulphate electrophoresis gave a single band corresponding to a molecular weight of 42 200 (after subtraction of the molecular weight of hGH), which differs significantly (p<0.01) from the values determined for the two distinct bands given by the microsomal fraction. Moreover, upon molecular sieve chromatography the receptor activity in the two fractions appeared at significantly (p<0.05) different elution volumes. These results show that the cytosolic and microsomal receptors have some structural features in common but are definitely not identical.
Inferior petrosal sinus sampling: Evidence of a stimulatory effect of oCRH on GH secretion in Cushing's Disease
Authors: Loli P. , Vignati F. , Scialfa G. , Boccardi E. , Branca V. , Berselli M. E.
Published: June 2009

Preoperative localization of ACTH-secreting microadenomas has been performed in 9 patients with Cushing's disease by using bilateral and simultaneous venous sampling of the inferior petrosal sinuses. In addition to ACTH and PRL we determined GH levels after oCRH stimulation in order to confirm the possible occurrence of unilateral GH increases, as recently observed by us in one patient. A central-to-peripheral and an intersinus gradient of ACTH concentration was observed in all patients examined before and/or after oCRH stimulation. In 7 patients central-to-peripheral and side-to-side PRL gradients were recorded in basal conditions; in 5 of these patients a unilateral oCRH-induced PRL increase was observed. Six out of the 7 patients with unilateral PRL increases also showed an intersinus GH gradient in basal conditions (ratio ≥ 1.5); in 5 of them a clearcut oCRH-induced GH increase was observed. A peripheral oCRH-induced GH and PRL increase was not observed in any of the patients. The observation of a paradoxical oCRH-induced GH increase in the inferior petrosal sinus with the higher ACTH concentration is of speculative and clinical interest; whether it reflects co-secretion of hormones by the tumour or hormone release by non-tumourous cells via paracrine mechanism is still to be clarified. The unilateral GH increase could represent an additional signal of the presence and localization of an ACTH-secreting tumour.
Binding of insulin-like growth factor-I to rat uterus; variations during sensitization and decidualization
Authors: Chandrasekhar Yallampalli , Narayan Satya , Singh Pomila , Nagamani Manubai
Published: June 2009

IGF-I receptors have been identified and characterized in a variety of tissues. In this study receptors for IGF-I in the rat uterine tissue were identified and characterized. We have demonstrated IGF-I receptors in crude uterine membranes by binding and cross-linking experiments. IGF-I binding to the rat uterine membranes displayed time, temperature and pH dependance, and optimal binding conditions were achieved by 20 h of incubation at 4°C, at a pH of 7.8. Uterine IGF-I binding sites were specific for binding IGF-I peptide and demonstrated less than 100 × lower affinity for insulin. The binding was reversible and Scatchard analysis indicated presence of a single class of binding sites with an apparent dissociation constant of 1.68 ± 0.24 nmol/l and Bmax of 0.82 ± 0.1 pmol/mg protein. During estrogen treatment, sensitization and decidualization there was an overall increase of membrane proteins in the uterus and a relative decrease of IGF-I receptors per unit of protein. When expressed on a per uterus basis, there was a progressive increment in total IGF-I binding in estradiol-treated, sensitized, and decidualized uterus compared with controls. These data indicate a possible role for IGF-I in uterine cell multiplication and further differentiation to decidual cells in response to deciduogenic stimuli.
Calcitonin causes a sustained inhibition of protein kinase C-stimulated bone resorption in contrast to the transient inhibition of parathyroid hormone-induced bone resorption
Authors: Ransjö Maria , Lerner Ulf H.
Published: June 2009

Calcitonin is a well known inhibitor of osteoclastic bone resorption, both in vivo and in vitro. However, it is also known that calcitonin has only a transient inhibitory effect on bone resorption. The mechanism for this so-called "escape from inhibition" phenomenon is not clear. In the present study, the inhibitory effect of calcitonin on phorbol ester-induced bone resorption was examined in cultured neonatal mouse calvaria. Bone resorption was assessed as the release of radioactivity from bones prelabelled in vivo with 45Ca. Two protein kinase C-activating phorbol esters, phorbol-12-myristate-13-acetate and phorbol-12,13-dibutyrate, both stimulated 45Ca release in 120-h cultures at a concentration of 10 nmol/l. Calcitonin (30 nmol/l) inhibited phorbol esterstimulated bone resorption without any "escape from inhibition". This was in contrast to the transient inhibitory effect of calcitonin on bone resorption stimulated by parathyroid hormone (10 nmol/l), prostaglandin E2 (2 μmol/l), and bradykinin (1 μmol/l). Our results suggest that activation of protein kinase C produces a sustained inhibitory effect of calcitonin on bone resorption.
Circadian patterns of serum insulin-like growth factor (IGF) II and IGF binding protein 3 in growth hormone-deficient patients and age- and sex-matched normal subjects
Authors: Jørgensen Jens Otto L. , Blum Werner F. , Møller Niels , Ranke Michael B. , Christiansen Jens S.
Published: June 2009

Knowledge of the circadian patterns of serum IGF-I I and the large molecular weight IGF binding protein, IGFBP-3 might, apart from its physiological relevance, be of clinical interest, inasmuch as measurements of these parameters are being introduced into the evaluation of GH deficiency. We therefore evaluated the 24-h (08.00-08.00 h) patterns of serum IGF-II and IGFBP-3 in 8 GH-deficient patients who were studied during three periods when receiving 1. GH (2 IU) at 20.00 h; 2. GH (2 IU) at 08.00 h and 3. no GH. For comparison, 10 age- and sex-matched untreated healthy subjects were studied once under similar conditions. The serum IGF-II levels of the patients were relatively stable over the 24-h periods, yielding mean levels which were significantly lower during no GH: 553±78 (evening GH), 554±54 (morning GH), and 429±65 μg/l (no GH). The mean IGF-II level in the normal subjects was 635±29 μg/l, which was significantly higher than in either patient study. Similarly, stable 24-h levels of IGFBP-3 were recorded in all studies. The mean IGFBP-3 level of the patients was significantly lower when they received no GH, and the mean level in the healthy subjects was higher than in any of the patient studies: 1853±301 (no GH), 2755 ± 317 (evening GH), 2904±269 (morning GH), and 3856±186 μg/l (healthy subjects). However, minute but significant changes over time, characterised by slight decrements at night, were observed for both parameters in several of the studies. Nevertheless, since both IGF-II and IGFBP-3 display rather stable 24-h levels in the individual, it is concluded that measurements of these parameters in evaluation of growth retardation can be based on a single daytime sample.
Androgen receptor disorder in three brothers with bifid prepenile scrotum and hypospadias
Authors: Bals-Pratsch Monika , Schweikert Hans-Udo , Nieschlag Eberhard
Published: June 2009

Three brothers with congenital transposition of the penis, scrotal hypospadias, bifid scrotum, and bilateral undescended testes are described. Further signs of incomplete virilization, but no gynecomastia were seen. LH and FSH were elevated, whereas testosterone levels were reduced or in the normal range. Serum concentrations of 17-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, 5α-dihydrotestosterone and estradiol measured in two affected brothers were in the normal range. Fibroblasts from scrotal skin biopsies performed in two patients showed normal 5α-reductase activity (419 and 214 pmol · (mg protein)−1 · h−1; normal >1), whereas androgen receptors had reduced maximal binding capacity (Bmax 4 and 14 fmol · (mg protein)−1; normal ≥ 18) and an increased equilibrium dissociation constant (0.7 and 1.26 nmol/l; normal 0.2±0.08) indicating a quantitative and qualitative androgen receptor defect. These patients represent a further variant of androgen insensitivity.
Thyroid-stimulating activity of human chorionic gonadotropin in sera of normal pregnant women
Authors: Yoshimura Masayoshi , Nishikawa Mitsushige , Horimoto Masateru , Yoshikawa Norio , Sawaragi Susumu , Horikoshi Yorihiko , Sawaragi Isamu , Inada Mitsuo
Published: June 2009

To ascertain the thyrotropic activity of human chorionic gonadotropin in sera of normal pregnant women, we examined the adenylate cyclase activation in the cultured FRTL-5 cells by extracted hCG from 7 normal pregnant women. hCG was extracted from the sera using anti-hCG-β subunit monoclonal antibodycoated microwells, eluted with 2 mol/l guanidine-HCl, and reconstituted with hypotonic Hanks' solution. FRTL-5 cells were precultured in 5H medium, incubated for 2 h with the serum extracts, and the cAMP released into the medium was measured. hCG levels in serum extracts ranged from 1100 to 6800 IU/l; values corresponded to 1.4-19.8% compared with those in the original serum samples. Addition of the extracts to FRTL-5 cells resulted in significant increases in the cAMP accumulation, ranging from 9.8 to 59.0 nmol/l. cAMP levels were also increased in a dose-dependent manner by adding purified hCG as well as crude hCG and hTSH to FRTL-5 cells. These findings suggest that the thyroid gland of normal pregnant women may actually be stimulated by hCG itself.
Pharmacokinetics of the antiprogesterone RU 486: No correlation to clinical performance of RU 486
Authors: Heikinheimo Oskari , Ylikorkala Olavi , Turpeinen Ursula , Lähteenmäki Pekka
Published: June 2009

The pharmacokinetics and metabolism of RU 486 were characterized in 17 women who received a single dose of 600 mg of RU 486 for termination of an early unwanted pregnancy. Based on the clinical outcome and serum chorionic gonadotropin values, the subjects were divided into two groups: those who aborted completely (i.e. responders; N=13) and those who did not respond to RU 486 treatment (i.e. non-responders; N = 4). The serum levels of RU 486, the monodemethylated, didemethylated and hydroxylated metabolites of RU 486 were measured by HPLC preceded by column chromatography. There were no significant differences in the serum levels of RU 486 or its metabolites between the two groups. The serum concentrations of α1-acid glycoprotein, the binding protein for RU 486, were quantitated by immunoturbidimetry. The α1-acid glycoprotein concentrations were similar in responders and non-responders. The metabolism of RU 486 was also studied by fractionating extracts of serum pools of responders and nonresponders on thin-layer chromatography, and subsequent RIA analysis of the eluates of the sliced thin-layer chromatography. Spots with similar distribution and percentages of cross-reactivity were found in both groups on the chromatography; the results were also similar to those from a serum pool to which synthetic RU 486 and its three metabolites had been added. Hence it is concluded that failure to abort in response to RU 486 therapy is not associated with altered pharmacokinetics or metabolism of RU 486.
A longitudinal study of total and free thyroid hormones and thyroxinebinding globulin during normal puberty
Authors: Dunger David B. , Perkins Janet A. , Jowett Terence P. , Edwards Philip R. , Cox Leslie A. , Preece Michael A. , Ekins Roger P.
Published: June 2009

Thyroid hormones are essential for normal pubertal growth, yet the changes in total and, especially, free thyroid hormones and thyroxine-binding globulin during puberty have not been adequately defined. Serum from 39 normal children (20 girls, 19 boys) between the ages of 10 and 15 years were assayed for total T4, free T4, free T3 and thyroxine-binding globulin at 6-monthly intervals; the free hormone assays were valid, non-analogue methodologies. In the girls, free T4 levels fell from 15.7±0.6 pmol/l at 10 years to 13.0±0.6 (p<0.001) at 12.5 years before rising to 15.9±0.7 at 15 years; this nadir occurred at puberty stages 3-4. Changes in total T4 followed a similar pattern with a slight delay in the nadir (13 years, puberty stage 4). In the boys, free T4 fell from 16.3±0.6 pmol/l at 10 years to 14.3±0.3 at 13.5 years, then rising to 15.4±0.5 at 15 years; the nadir again occurred at puberty stages 3-4. The corresponding nadir in total T4 which occurred at puberty stages 4-5 was not apparent by age analysis. Thyroxine-binding globulin concentrations remained unchanged in the girls, but fell slightly in the boys during later puberty. Free T3 concentrations in the girls showed a progressive fall after 12.5 years which was significant by the age of 14 when most had been in puberty stage 5 for more than 1 year. The boys showed no change of free T3 concentration throughout the study. These data demonstrate important differences in the levels of free thyroid hormones in males and females during puberty. Normal ranges for girls and boys between the ages of 9.5 and 15.5 years are presented.
Antithyroid drug treatment of Graves' disease in pregnancy: Long-term effects on somatic growth, intellectual development and thyroid function of the offspring
Authors: Messer Peter M. , Hauffa Berthold P. , Olbricht Thomas , Benker Georg , Kotulla Peter , Reinwein Dankwart
Published: June 2009

With regard to their thyroid function, somatic and intellectual development, we compared 17 children of 13 hyperthyroid mothers (group I) receiving antithyroid drug treatment during their pregnancies with 25 children of 15 mothers who were euthyroid without any antithyroid treatment during their pregnancy (group II). Mean duration of maternal treatment was 3.5 months in group I, using carbimazole or thiamazole (N=12) and propylthiouracil (N=1). Age at examination in group I was 7.2±6.2 years, in group II 8.7±7.1 years (mean±sd). Both groups showed no significant differences in the results of the clinical examination and in the degree of their mental and psychomotoric development at the time of study. We found the mean birth weight of the infants in group I significantly lower than in group II(3165±339 vs 3666±670 g, p<0.03). The individual birth weights, however, were normal for gestational age. The body weight difference between groups disappeared during the further somatic development of the children. The serum concentration of free thyroxine in group I was significantly higher than in group II (17.2 ± 2.4 vs 14.9±1.9 pmol/l, p<0.003), but fell in both groups within the normal range. The evaluation of the psychomotoric and intellectual capacity of the children at different developmental stages showed no abnormalities detectable by our tests. Thus, in the children of the two groups we found no adverse effects of a maternal antithyroid drug treatment during pregnancy or of inactive maternal Graves' disease alone, neither on thyroid gland size and function nor on the physical or intellectual development, after the neonatal period.
Monoclonal antibodies reveal circulating growth hormone of high molecular weight not detectable by conventional assays
Authors: Luthman Marguerite , Jónsdóttir Ingileif , Skoog Bo , Wivall Inga-Lena , Roos Paul , Werner Sigbritt
Published: June 2009

A radioimmunoassay based on a monoclonal antibody, Mc-ab 1, which was raised against growth hormone but cross-reacted with human placental lactogen yielded higher GH immunoreactivity levels in serum than one based on a polyclonal antiserum. This discrepancy was noted in subjects with normal GH secretion as well as in patients with GH insufficiency. To characterize this GH immunoreactivity detected by Mc-ab 1, affinity purification and molecular sieve chromatography of serum were performed. High molecular weight proteins with GH immunoreactivity were found with both techniques. These proteins were associated with carbohydrates. Affinity cross-linking showed specific binding of radiolabelled GH to high molecular weight proteins in the serum. After fractionation of serum, the GH immunoreactivity became detectable by the polyclonal antiserum assay as well as by an immunoradiometric assay. GH immunoreactive material with an approximate mass of 80 kD was subjected to isoelectric focusing. When GH immunoreactive fractions at pH 5 were re-chromatographed, GH immunoreactivity was recovered in the elution volume corresponding to monomeric GH. Our results show that sera from normal subjects as well as from patients with deficient GH secretion contain notable amounts of high molecular weight GH which is undetectable by antibodies generally used for GH measurements, but which can be revealed after fractionation of serum.
The corticotropin-releasing factor test in the differential diagnosis of Cushing's syndrome: A comparison with the lysine-vasopressin test
Authors: Tabarin A. , Galli F. San , Dezou S. , Leprat F. , Corcuff J.-B. , Latapie J.-L. , Guerin J. , Roger P.
Published: June 2009

The diagnostic accuracy of the CRH test was compared with that of the LVP test in 28 consecutive patients with ACTH-dependent Cushing's syndrome. A false negative response to CRH was found in 3 of 21 patients with pituitary-dependent Cushing's disease and to LVP in 4. The 7 patients with ectopic ACTH secretion were unresponsive to CRH, whereas 2 did respond to LVP. CRH and high-dose dexamethasone tests combination led to concordant results in 79% of patients. In all cases the etiological diagnosis suggested was correct. LVP and high-dose dexamethasone tests combination led to concordant results in only 71% of patients and the etiological diagnosis suggested was erroneous in one. Individual tolerance to the CRH test was also clearly better than that to the LVP test. It is concluded that the CRH test, alone or in combination with the high-dose dexamethasone test must be preferentially used to the LVP test in the differential diagnosis of ACTH-dependent Cushing's disease.
Influence of growth hormone on the immunosuppressive effect of prednisolone in mice
Authors: Franco P. , Marelli O. , Lattuada D. , Locatelli V. , Cocchi D. , Müller E. E.
Published: June 2009

Growth hormone can be used to counteract some catabolic effects of long-term administration of glucocorticoids, such as impairment of growth in children and osteoporosis. However, owing to its immunostimulatory properties the hormone may counteract the effect of glucocorticoids on the immune system. To investigate this question we administered different doses of hGH (4, 8, 40 IU/kg) to C57/B1/6J mice treated for two days with prednisolone, and evaluated thymus and spleen parameters and natural killer activity. Growth hormone at the dose of 4 and 8 IU/kg reversed prednisolone-induced reduction of spleen and thymus weight and cellularity, whereas the highest dose showed to be immunosuppressive in itself. Two days after treatment withdrawal, a recovery of spleen parameters was evident, whereas the thymus was still suppressed by preceding prednisolone or hGH (40 IU/kg) treatments. The pattern of natural killer activity displayed by the splenocytes resembled that present under treatment. In a second experiment prednisolone, administered for 10 days, drastically reduced the number of viable spleen and thymus cells as well as the relative spleen and thymus weights, an effect reversed by concomitant administration of hGH (0.8, 4, 8 IU/kg). Natural killer activity, which was significantly depressed by prednisolone, was restored by the intermediate GH dose only. The 8 IU/kg GH dose was immunosuppressive in itself.
Evidence for LH-inhibiting activity in ovine peripheral and testicular blood
Authors: Papapdopoulos V. , Kamtchouing P. , Boujrad N. , Pisselet C. , Perreau C. , Locatelli A. , Drosdowsky M. A. , de Reviers M. T. Hochereau , Carreau S.
Published: June 2009

Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 μg/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season. The addition of peripheral plasma leads to a testosterone production equal to 35 and 65% of the oLH-stimulated values, respectively, for ram blood collected in non-breeding and breeding seasons. The same concentration of ovine testicular lymph or rete testis fluid is without significant effect on cyclic AMP production; however, testosterone is slightly decreased by lymph but enhanced by rete testis fluid. Increasing amounts of venous or arterial testicular blood induce a dose-related decrease of the specific binding of labelled hCG in both rat and ram testicular membranes. This inhibiting factor is present in peripheral and testicular blood of either control or hypophysectomized or castrated rams, is a protein in nature, heat-sensitive, and has an apparent molecular weight higher than 10 000 daltons. These results suggest the existence of a control of LH-specific binding to its receptors and of Leydig cell cyclic AMP and testosterone outputs; these activities are not species-specific and are more concentrated in testicular venous than in arterial blood. The origin of this inhibiting factor remains to be determined, since it is not confined to the testis and not of pituitary origin.
The source of cholesterol for progesterone synthesis in cultured preovulatory human granulosa cells
Authors: Endresen Marit J. , Haug Egil , Åbyholm Thomas , Henriksen Tore
Published: June 2009

There are three possible sources of cholesterol for immediate use in progesterone production by preovulatory human granulosa cells: follicular fluid high-density lipoprotein, de novo synthesis of cholesterol, and preformed intracellular cholesteryl ester stores. In the present study these three alternatives were investigated. First, an in vitro model was established that mimics the preovulatory environment, including short-term cultures and use of autologous follicular fluid in the culture medium, instead of serum. Using this model it was found that the presence of high-density lipoprotein from follicular fluid in the culture medium did not affect the synthesis of progesterone by the granulosa cells. Next, addition of inhibitors of de novo sterol synthesis, like low-density lipoprotein, 25-OH cholesterol and compactin to the culture medium, did not reduce [14C]acetate incorporation into sterols and steroids by the cells. The sterol synthesis was accordingly interpreted to be at a low and therefore uninhibitable level. Finally, the content of free and esterified cholesterol in freshly isolated granulosa cells was found to be 50±7 and 52±13 pmol/mg cell protein, respectively. We suggest that neither follicular high-density lipoprotein nor endogenous synthesis is the imim- cholesterol source for the progesterone production in preovulatory human granulosa cells. However, granulosa cells have a large store of cholesteryl esters that may provide free cholesterol for the preovulatory progesterone production.
Steroid hydroxylase gene expression in the ovine fetal adrenal gland following ACTH infusion
Authors: Tangalakis Kathy , Coghlan John P. , Crawford Robert , Hammond Vicki E. , Wintour E. Marelyn
Published: June 2009

Between 90 and 120 days of gestation (term = 147±5), when plasma cortisol concentrations in the fetus are at a minimum, levels of mRNA encoding the steroidogenic enzymes 17α-hydroxylase (P-45017α) and cholesterol side-chain cleavage (P-450scc) are also very low. Over the following 30 days, P-45017α and P-450scc gene expression increases concurrent with increasing fetal cortisol concentration. The hypothesis tested in this study was that cortisol biosynthesis is minimal in the period 90-120 days because of insufficient ACTH. Fetuses were cannulated between 98-102 days of gestation. Following recovery, 7 fetuses received 24-h ACTH infusions (12 μg/24 h) and 5 fetuses received 24-h vehicle infusions; 4 ACTH-infused and 4 vehicle-infused fetuses were then sacrificed immediately after cessation of the infusion. The other fetuses were left in utero for 3 days prior to sacrifice. Fetal blood samples were analysed for ACTH and cortisol and the adrenals processed for hybridization histochemistry and Northern blot analysis. ACTH, but not vehicle, induced significant increases in the width of the adrenal cortex and in the levels of P-45017α and P-450scc mRNA. Concurrently, fetal plasma ACTH and cortisol concentrations also increased significantly. In adrenals from fetuses left in utero for 3 days after cessation of the ACTH infusion, P-45017α and P-450scc mRNA levels returned to control levels. Plasma ACTH and cortisol levels also approximated basal values. P-450c21 mRNA levels did not vary significantly at any time with the treatments. It can be concluded that the major regulatory influence on ACTH in the 90-120 day fetus is via increased gene expression of P-45017α and P-450scc but not P-450c21.
Intravenous administration of recombinant IGF-I lowers serum GHRH and TSH
Authors: Laron Z. , Klinger B. , Silbergeld A. , Lewin R. , Erster B. , Gil-Ad I.
Published: June 2009

Recombinant IGF-I was administered as an iv bolus of 75 μg/kg to 10 patients with Laron type dwarfism (3 children aged 9, 11 and 12 years and 7 adults aged 30.6 ± 3.5 years) and to 8 healthy subjects (mean age 19.9 ± 12.1 years) and determinations of IGF-I, GHRH, hGH, TSH, and glucose were made before and at 2, 5, 15, 30, 60, 90, and 120 min. The following effects were observed: a. an immediate, marked and sustained drop in blood glucose (p < 0.001), more prolonged in the patients; b. in both groups, a dramatic rise in plasma hGH (p<0.01) which peaked at 60-90 min; in the patients this occurred after an initial immediate fall in plasma hGH (p<0.01); c. a progressive decrease of plasma GHRH and TSH (p<0.05, 0.02) in both patients and healthy controls. An hypothesis is put forward that acute and time-limited release of somatostatin by IGF-I is the main cause of the hormonal changes registered. As the IGF-I bolus also suppressed circulating insulin levels, the hypoglycemia is considered to be a direct effect of IGF-I.
Thyroid size and function in healthy pregnant women with thyroid autoantibodies. Relation to development of postpartum thyroiditis
Authors: Rasmussen Nini G. , Hornnes Peter J. , Høier-Madsen Mimi , Feldt-Rasmussen Ulla , Hegedüs Laszlo
Published: June 2009

In a study of postpartum thyroiditis, thyroid function and ultrasonically determined thyroid size were evaluated in 36 thyroid autoantibody positive healthy women during pregnancy and the first postpartum year. Twelve women (33%) developed postpartum thyroiditis with permanent thyroid dysfunction in three. However, only one woman had symptoms and needed treatment. The most common type of thyroid dysfunction was a transient hyperthyroid phase as seen in 7 women. A significant increase by 20-30% in mean thyroid volume during pregnancy was demonstrated independent of development of postpartum thyroiditis. We conclude that initial thyroid volume or changes during pregnancy and post partum are not useful indicators of the development of postpartum thyroiditis. The fact that the condition is oligosymptomatic suggests that screening procedures are necessary if one wants to diagnose the earliest phases of postpartum thyroiditis.
Parathyroid localization by 201Tl-99mTc subtraction scintigraphy: Results in secondary hyperparathyroidism
Authors: Rademaker Paul , Meijer Sijtze , Piers Do A.
Published: June 2009

Subtraction scintigraphy with 201Tl and 99mTc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands.
Changes in thyroid volume during antithyroid drug therapy for Graves' disease and its relationship to TSH receptor antibodies, TSH and thyroglobulin
Authors: Yamaguchi Yoshiyuki , Inukai Toshihiko , Iwashita Akira , Nishino Michio , Yamaguchi Takahiko , Shohda Yoshihito , Shimomura Yohnosuke , Ohshima Kihachi , Kobayashi Setsuo , Kobayashi Isao
Published: June 2009

Changes in thyroid volume during antithyroid drug therapy for Graves' disease compared with circulating thyroid parameters were evaluated. One hundred and forty-four patients with Graves' disease were treated with methimazole. Thyroid volume was measured by ultrasonography (thyroid volume = Π abc/6, where a is length, b width, and c depth). Serum TSH, TSH-binding inhibitory immunoglobulins, thyroid-stimulating antibodies, thyroglobulin, antimicrosomal antibodies, and antithyroglobulin antibodies were also measured. In the whole group of patients, thyroid volume correlated significantly with thyroglobulin (p<0.01) and TSH-binding inhibitory immunoglobulins (p<0.01), but not with TSH, antimicrosomal antibodies, and antithyroglobulin antibodies. Furthermore, a positive correlation was found between thyroglobulin and TSH-binding inhibitory immunoglobulins (p<0.01). In 11 patients the mean thyroid volume decreased significantly after one year of therapy (p<0.01), associated with decreasing levels of serum TSH-binding inhibitory immunoglobulins. Ten patients experienced transient hypothyroidism with an overdose of methimazole, and the mean thyroid volume increased significantly (p<0.01) with increasing serum TSH levels. In conclusion, it is suggested that TSH receptor antibodies may have a thyroid growth-stimulating effect. In addition, circulating thyroglobulin levels reflect thyroid volume in Graves' disease.
Incidence of intratubular germ cell neoplasia in androgen insensitivity syndrome
Authors: Cassio Alessandra , Cacciari Emanuele , D'Errico Antonia , Balsamo Antonio , Grigioni Franco W. , Pascucci Maria G. , Bacci Francesco , Tacconi Moreno , Mancini Antonio M.
Published: June 2009

Gonadal histology was investigated by means of conventional microscopy in 6 patients with complete androgen insensitivity syndrome, in 11 with incomplete androgen insensitivity syndrome, and in 3 with 5α-reductase syndrome. Twelve subjects were prepubertal and 8 pubertal. In all patients gonadal tissue was removed as a prophylactic measure and no patients gave rise to any clinical suspicion of a tumour. Eight patients with incomplete androgen insensitivity syndrome, 5 of whom (62.5%) were prepubertal, showed intratubular germ cell neoplasia and in 6 of them it was bilateral. Histochemical and immunohistochemical analysis showed considerable agreement between atypical morphological aspects and positive response to Schiff's periodic acid and to staining with the anti-placenta alkaline phosphatase antibody. Our patients were characterized by one of the highest reported incidences of intratubular germ cell neoplasia, particularly at prepubertal age. These findings would seem to indicate that a rethink is needed concerning the general opinion that patients with androgen intensivity syndrome have practically no risk of developing malignancy, and that orchidectomy is not advisable before puberty is completed.
A critical evaluation of transsphenoidal pituitary surgery in the treatment of Cushing's disease: Prediction of outcome
Authors: Arnott Richard D , Pestell Richard G , McKelvie Penelope A , Henderson J Keith , McNeill Peter M , Alford Frank P
Published: June 2009

Twenty-eight patients underwent transsphenoidal pituitary surgery for Cushing's disease. Selective surgical procedures were performed in 26. In 19 patients pituitary adenoma was confirmed histologically and 5 had clumps or clusters of ACTH-staining cells. At follow-up after 22.3 (range 5-56) months 21 (75%) patients remained in clinical and biochemical remission. The 24-h urinary free cortisol performed between 1 and 4 weeks postoperatively while patients took replacement doses of dexamethasone (0.5 to 0.75 mg per day) was found to predict outcome. All patients with suppressed urinary free cortisol excretion have remained in remission, 3 with levels in the normal range have suffered late relapse after initial remission, and 4 with elevated urinary free cortisol excretion were regarded as having failed to remit. Furthermore, all patients with unsuccessful outcomes had no pituitary adenoma and 3 had features consistent with corticotrope nodular hyperplasia at histological examination compared to only 2 and 1, respectively, of patients still in remission. We conclude that 24-h urinary free cortisol performed at 1 to 4 weeks postoperatively whilst on low-dose dexamethasone and the histological findings may predict outcome following transsphenoidal pituitary surgery in Cushing's disease.
Thyroid peroxidase/microsomal antibodies are not identical with thyroid cytotoxic antibodies in autoimmune thyroiditis
Authors: Bogner Ulrich , Kotulla Peter , Peters Harm , Schleusener Horst
Published: June 2009

Cytotoxic activity in sera of patients with Hashimoto's thyroiditis was measured with an antibody-dependent cell-mediated cytotoxicity assay. Cytotoxicity was determined in a 51chromium release assay using human thyroid cell targets incubated with heat-inactivated serum or IgG from patients with Hashimoto's thyroiditis. Effector cells were obtained from peripheral mononuclear cells of normal subjects. Cytotoxicity was significantly increased in patients with Hashimoto's thyroiditis (median specific lysis 20.2%, range 2.1-58.8) compared with normals (median specific lysis 8.1%, range 0-19.5; p<0.00001). The amount of percent specific lysis did not correlate with the titres of microsomal antibodies determined by different methods: passive hemagglutination technique (r=0.2), enzyme immunoassay with microsomal antigen (r=0.16), and radioimmunoassay for thyroid peroxidase antibody (r=0.02). The cytotoxic activity was located in the IgG fraction, both in microsomal antibody positive and negative sera. After pre-incubation of microsomal antibody/thyroid peroxidase antibody positive or negative sera with purified thyroid peroxidase followed by analysis in the antibody-dependent cell-mediated cytotoxicity assay, cytotoxicity decreased in only 2 cases but was unchanged in the remaining sera. Western blot experiments with solubilized thyroid membranes and immunoblotting with cytotoxic-positive/microsomal antibody negative sera showed no binding to thyroid peroxidase. Our data suggest that cytotoxicity in sera from patients with Hashimoto's thyroiditis is not mediated by antibodies against thyroid peroxidase, but by antibodies not yet identified.
Not all insulin secretagogues sensitize pancreatic islets to recombinant human interleukin 1β
Authors: Johannesen Jesper , Helqvist Steffen , Nerup Jørn
Published: June 2009

The purpose of this study was to test the influence of different insulin secretagogues on interleukin 1β mediated injury to isolated rat pancreatic islets. Islets were exposed to interleukin 1β for 6 days. During exposure, beta-cells were stimulated with glucose ( 11 mmol/l vs 3.3 mmol/l or with non-nutrients as tolbutamide (250 μmol/l), iso-butyl 1-methyl-xanthine (50 μmol/l), or glucagon (10 mg/l). At 3.3 mmol/l of glucose, 60 000 U/l of interleukin 1β caused an inhibition of medium insulin accumulation to 62±5% of control from 48 h to 6 days of exposure, whereas islet DNA content was unaffected. At 11 mmol/l of glucose, interleukin 1β dose-dependently decreased medium insulin accumulation (e.g. 60 000 U/l of interleukin 1β, 12±3% of control) and islet content of DNA (60 000 U/l of interleukin 1β, 60±8% of control). During beta-cell stimulation with tolbutamide, interleukin 1β caused inhibition of insulin accumulation to 36±9% of control. In contrast, on islets stimulated with iso-butyl 1-methyl-xanthine or glucagon, the effects of interleukin 1 β were equivalent to those on non-stimulated islets. These differences were paralleled by differences in the interleukin 1β effect on islet morphology. In conclusion, high beta-cell activity (as measured by islet insulin release) may increase islet susceptibility to interleukin 1β, however, depending upon the intracellular pathway through which insulin secretion is activated.
Diurnal variation in melatonin effect on adenosine triphosphate and serotonin release by human platelets
Authors: Del Zar María de las M. , Martinuzzo Marta , Cardinali Daniel P. , Carreras Luis O. , Vacas María I.
Published: June 2009

The effect of the pineal hormone melatonin on adenosine diphosphate-induced human platelet aggregation and adenosine triphosphate release was assessed in platelet-rich plasma obtained from normal volunteers at 08.30 and 20.30 h. In 10−7-10−5 mol/l concentrations melatonin inhibited ADP-induced platelet aggregation only in the evening (p<0.05). ADP-induced ATP release, an index of platelet secretory processes, showed a generally greater, dose-dependent inhibition after adding melatonin (10−9-10−5 mol/l) at 20.30 h as compared with 08.30 h. The inhibitory activity of melatonin (10−9-10−5 mol/l) on [3H]serotonin release elicited by thrombin in washed human platelets obtained from normal volunteers was dose-dependent; the effect was generally greater at 20.30 h. The activity of the potent platelet anti-aggregating agent prostacyclin did not exhibit diurnal differences with respect to impairing ADP-induced platelet-rich plasma aggregation. These results indicate the existence of a diurnal variation of sensitivity to melatonin in human platelets.
Action and formation of inositol bisphosphate and inositol trisphosphate in rat anterior pituitary cells
Authors: Przylipiak Andrzej F. , Kiesel Ludwig , Karenberg Thomas A. , Przylipiak Maria S. , Runnebaum Benno
Published: June 2009

Inositol 4,5-bisphosphate and inositol 1,4,5-trisphosphate, administered exogenously at a concentration of 3× 10−5 mol/l increased LH release in superfused rat pituitary cells by 950±267% and 281±83%, respectively. This stimulatory effect was reversible and dose-dependent. Other inositol phosphates (inositol 1-monophosphate, inositol 1,4,5,6-tetrakisphosphate, inositol 1,3,4,5,6-pentakisphosphate and inositol 1,2,3,4,5,6-hexakisphosphate), tested in vitro, did not significantly influence LH release. In saponin-permeabilized cells, the rate of basal and stimulated LH release was twice that in non-permeabilized cells. Penetration of inositol bisphosphate and inositol trisphosphate into saponin-treated pituitary cells did not increase the secretory potency of these agents compared with their effect on non-permeabilized cells. The new findings document that inositol trisphosphate formation occurs within 5-45 s after GnRH (10−7 mol/l) administration and seems to be involved in mediating the rapid, first phase of LH release, whereas inositol bisphosphate formation occurs after 3-15 min and is probably related to later phases of LH secretion. Our results suggest that inositol bisphosphate and inositol trisphosphate are important regulators of the release of luteinizing hormone and can exert their effects not only intracellularly, but also extracellularly.
Relationship between molecular structures of sugars and their ability to stimulate the release of glucagon-like peptide-1 from canine ileal loops.
Authors: Shima Kenji , Suda Takeo , Nishimoto Kayo , Yoshimoto Sachiko
Published: June 2009

The structure-activity relationship of sugars inducing secretion of glucagon-like peptide-1 from the gut was examined using intestinal loops prepared from the terminal portion of the ileum of dogs. The plasma glucagon-like peptide-1 concentration in a mesenteric vein draining only the looped region of the intestine was increased after infusion of 139 mmol/l solutions of D-glucose, D-galactose, D-glucuronic acid, 3-0-methyl-D-glucose, maltose, sucrose or maltitol into the intestinal lumen, but not after infusion of solutions of D-fructose, D-fucose, D-mannose, D-xylose or lactose. The increases in plasma glucagon-like peptide-1 concentration correlated with the corresponding increases in glucagon-like immunoreactivity induced by these sugars. The plasma glucose level of the regional mesenteric vein increased significantly from the basal level after instillation of D-glucose, but not after instillation of other sugars. It is suggested that cells of the gut have a glucose sensor for release of products of the glucagon gene and that this sensor has specific steric requirements. The sugars that induced glucagon-like peptide-1 release share the molecular features of electron density near C(6), an equatorial hydroxyl at C(2), and an axial hydroxyl at C(1), which could account for their recognition by the glucose sensor to initiate the releases of glucagon-like peptide-1 and glucagon-like immunoreactivity.
Interleukin 1β and tumour necrosis factor α stimulate the release of gonadotropin-releasing hormone and interleukin 6 by primary cultured rat hypothalamic cells
Authors: Yamaguchi Masaaki , Yoshimoto Yasuhiro , Komura Hiroko , Koike Koji , Matsuzaki Noboru , Hirota Kenji , Miyake Akira , Tanizawa Osamu
Published: June 2009

The abilities of recombinant human interleukin 1β and tumour necrosis factor α to induce release of GnRH and interleukin 6 from primary culture of rat hypothalamic cells were examined. The effect of estradiol on the release of interleukin 6 by these cells was also tested. Both interleukin 1β and tumour necrosis factor α caused significant stimulation of GnRH secretion from the hypothalamic cells within 5 min. The hypothalamic cells secreted interleukin 6 spontaneously, and their secretion over 24 h was stimulated dose-dependently by interleukin 1β, tumour necrosis factor α and estradiol. These results suggest that interleukin 1β and tumour necrosis factor α stimulate the secretions of GnRH and interleukin 6 in the hypothalamus, and that these cytokines may be involved in the mechanism of GnRH secretion in the hypothalamus.