bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of bromocriptine and SMS 201-995 on growth of human somatotrophic and non-functioning pituitary adenoma cells in vitro
Authors: Renner Ulrich , Mojto Juri , Lange Manfred , Müller O Albrecht , von Werder Klaus , Stalla Günter K
Published: December 2008

Renner U, Mojto J, Lange M, Albrecht Müller O. von Werder K, Stalla GK. Effect of bromocriptine and SMS 201-995 on growth of human somatotrophic and non-functioning pituitary adenoma cells in vitro. Eur J Endocrinol 1994;130:80–91. ISSN 0804–4643

The effect of the dopamine agonist bromocriptine and the somatostatin analog SMS 201-995 on growth of 12 human somatotrophic and 13 non-functioning adenoma cell cultures was investigated. When adenoma cells were maintained in medium supplemented with 5% fetal calf serum. cell counts of 10 of 12 somatotrophic cultures increased to 145±6 and 171 ±9% (mean±sd) and in 12 of 13 non-functioning cell cultures up to 125±12 and 217±15% after 3 days of incubation. In most cases bromocriptine and SMS 201-995 dose dependently (1 nmol/l to 10 μmol/l) inhibited adenoma cell growth but there was only (1.10 μmol/l) a significant inhibitory effect at high doses of both drugs. A 1 μmol/l concentration of bromocriptine decreased cell counts of 5 of 12 somatotrophic cell cultures (range 84±3 to 76±6% vs control = 100%) and in 5 of 13 non-functioning cell cultures (range 85±4 to 71 ± 7%). A 10 μmol/l concentration of bromocriptine decreased cell counts in all 12 somatotrophic (range 87±1 to 61 ±8%) and in 12 of 13 non-functioning adenoma cultures (range 87±6 to 57±3%). Bromocriptine specifically inhibited growth because its effect could be reversed by the dopamine D2-receptor antagonist haloperidol. Both 1 and 10 μmol/l SMS 201-995 significantly decreased cell counts in three of six somatotrophic (87± 3 to 38 ±3%) cell cultures. In two of five cases growth of non-functioning adenoma cultures was suppressed by 1 μmol/ISMS 201-995, and in four of five cases by 10 μmol/l(86± 3 to 74 ±4%). The growth inhibitory effect of both bromocriptine and SMS 201-995 was not just due to an effect on growth of fibroblasts contaminating the adenoma cell cultures, because it could be observed also when adenoma cells were maintained in a d-valine-supplemented medium that suppresses fibroblast growth. In summary, both bromocriptine and SMS 201-995 at high doses were able to inhibit cell growth of cultured somatotrophic and non-functioning adenomas in vitro. However, the mechanism of this inhibitory effect is not yet well understood.

Ulrich Renner, Max-Planck-Institute of Psychiatry, Clinical Institute, Kraepelinstr. 10, D-80804 Munich, Germany
Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness
Authors: Custro Nicola , Scafidi Vincenza , Gallo Salvatore , Notarbartolo Alberto
Published: December 2008

Custro N, Scafidi V, Gallo S, Notarbartolo A. Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness. Eur J Endocrinol 1994;130:132–6. ISSN 0804–4643.

Twenty-four-hour thyrotropin (TSH) profiles in eight severely ill patients were compared with those of six healthy subjects. The profiles were assessed using the cosinor method to evaluate circadian variations and using the Pulsar algorithm to analyze episodic secretion. In the normal subjects, the typical periodicity of TSH secretion showed a mean level in the rhythm (mesor) of 2.03 mU/l, The amplitude (half the extent of rhythmic change in the cycle) was 0.58 mU/l; the acrophase (the delay from midnight (0 degrees) of the highest level in the rhythm) was −9.9 degrees. In contrast, severely ill patients showed only slight and anticipated elevations of serum TSH levels (mesor 0.93 mU/l, amplitude 0.22 mU/l, acrophase +82.4 degrees). Moreover, whereas the episodic TSH secretion in healthy individuals consisted of 5–8 pulses/24 h, mainly clustered around midnight, only one pulse of reduced amplitude was detected in two of the eight severely ill patients and no pulses in the other six. Since earlier studies have indicated that the loss of TSH pulsatility is associated with the relative insensitivity of the thyrotrophs to low thyroid hormone levels and our analytical procedures have demonstrated that 24 h pulsatile pattern of TSH closely overlapped with baseline TSH secretion, it seems reasonable to assume that low-thyroid-hormone state, deficient pulsatile TSH secretion and altered nyctohemeral TSH periodicity do not coincide by chance, but that there is a causal relationship between such abnormalities in severely ill patients.

Nicola Custro, Cattedra di Patologia Medica, Via del Vespro, n.141, 90127 Palermo, Italy
Calcium mobilization is a prerequisite for the expression of phorbol ester-stimulated luteinizing hormone secretion from pituitaries of male and acutely ovariectomized rats
Authors: Das Saswati , Fahmy Nabil W , Bourne Gregory A
Published: December 2008

Das S, Fahmy NW, Bourne GA. Calcium mobilization is a prerequisite for the expression of phorbol esterstimulated luteinizing hormone secretion from pituitaries of male and acutely ovariectomized rats. Eur J Endocrinol 1994;130:151–8. ISSN 0804–4643

Ionomycin, which mobilizes Ca2+, and phorbol 12-myristate 13-acetate (PMA) which activates protein kinase C (PKC), were used to compare the effects/interactions of Ca2+ and PKC on luteinizing hormone (LH) secretion from pituitaries of intact male and acutely ovariectomized (72 h) rats. Quartered pituitaries from donor animals were perifused at 0.25 ml/min and sequential effluent fractions were collected every 10 min. Continuous administration (4 h) of 1 nmol of gonadotropin-releasing hormone (GnRH) resulted in an increase in LH secretion. Cycloheximide (5 μmol) dissociated the GnRH-stimulated LH responses into protein synthesis-independent and -dependent components. While ionomycin (10 μmol) stimulated LH secretion from pituitaries of both sexes by protein synthesis-independent mechanisms, PMA (1 μmol) and the inactive phorbol ester, 4α-phorbol 12,13-didecanoate (PDD), were ineffective secretagogues. However, PMA (but not PDD) interacted synergistically with ionomycin and GnRH to augment LH secretion by protein synthesis-dependent mechanisms. These results suggest a similarity in the effects/interactions of Ca2 + and PKC in gonadotropes from male and ovariectomized rats. If the effects of PMA can be attributed to PKC activation, then it also appears that Ca2+ mobilization is necessary for the manifestation of PKC as a mediator of LH secretion from these gonadotropes. While PKC activity can be divorced from the protein synthesis-independent component of LH release (this component appears to be mediated by Ca2+ mobilization), the enzyme might be involved in amplifying the response to Ca2+ mobilization through synergistic, protein synthesis-dependent mechanisms.

Gregory Bourne, Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWO
Stimulation of sex hormone-binding globulin mRNA and attenuation of corticosteroid-binding globulin mRNA by triiodothyronine in human hepatoma cells
Authors: Barlow John W , Crowe Timothy C , Cowen Neil L , Raggatt Lorna E , Topliss Duncan J , Stockigt Jan R
Published: December 2008

Barlow JW, Crowe TC, Cowen NL, Raggatt LE, Topliss DJ, Stockigt JR. Stimulation of sex hormone-binding globulin mRNA and attenuation of corticosteroid-binding globulin mRNA by triiodothyronine in human hepatoma cells. Eur J Endocrinol 1994;130:166–70. ISSN 0804–4643

We examined the time course and dose response of the triiodothyronine (T3) effect on mRNAs for sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) in cells of the human hepatoma line HepG2. After 7 h of exposure to a saturating dose of T3, SHBG mRNA was unchanged but increased to 1.5±0.1 times the unstimulated control at 22 h. Maximal stimulation (2.3±0.6) was observed at 2–3 days. Corticosteroid-binding globulin mRNA was unchanged for 22 h after exposure to T3 but diminished thereafter to 64% by day 3. At 3–4 days of exposure, the changes in both SHBG mRNA and CBG mRNA were dose-responsive to the T3 concentration. For both mRNAs, half-maximal response occurred between 10 and 20 pmol/l bioavailable T3. Cortisol-binding proteins secreted by HepG2 cells after 3 days in culture also were T3 dose-responsive. No re-uptake of secreted CBG by the cells was observed, suggesting that the T3 effect on CBG secretion occurs during production of the mature protein. These data suggest that T3 stimulates the expression of the SHBG gene and attenuates the expression of the CBG gene. The effects of T3 on these genes are consistent with the increase in circulating SHBG and decrease in circulating CBG observed in hyperthyroidism. The HepG2 cells may be a useful human cell line in which to study the diversity of the molecular mechanisms of T3 action.

JW Barlow, Ewen Downie Metabolic Unit, Alfred Hospital, Commercial Rd. Melbourne, Victoria 3181, Australia
Effect of the antiglucocorticoid RU486 on adrenal steroidogenic enzyme activity and steroidogenesis
Authors: Albertson Barry D , Hill R Blake , Sprague Kellie A , Wood Karen E , Nieman Lynnette K , Loriaux D Lynn
Published: December 2008

Albertson BD, Hill RB, Sprague KA, Wood KE, Nieman LK, Loriaux DL. Effect of the antiglucocorticoid RU486 on adrenal steroidogenic enzyme activity and steroidogenesis. Eur J Endocrinol 1994;130: 195–200. ISSN 0804–4643

RU486, a synthetic steroid receptor antagonist, has strong antiprogesterone and antiglucocorticoid properties. Chronic RU486 administration in two patients with ectopic secretion of adrenocorticotropin (ACTH) has been associated with decreasing plasma cortisol concentrations. One explanation of this finding is that RU486 may directly inhibit adrenal steroidogenesis. To test this hypothesis, we measured the effect of RU486 on specific steroidogenic enzymatic steps using an in vivo rat and an in vitro monkey model. Hypophysectomized–castrated–ACTH-replaced Sprague-Dawley rats were given RU486 i.p. at daily doses of 0, 0.0005, 0.005, 0.05, 0.5 and 5 mg/kg body weight per day for 7 days. The animals were sacrificed, and blood and adrenal glands collected. Adrenal cortical mitochondria and microsomes were purified from the rats and from two untreated Cynomolgus macaque monkeys. Specific steroidogenic enzyme activities were measured in the rat by the incorporation of 14C-labeled steroid substrates into products. A similar protocol was used to assay the steroidogenesis in the monkey adrenal fractions in the presence and absence of added RU486. Although rat adrenal weights decreased significantly at the highest RU486 dose, plasma levels of corticosterone were similar in control and treated rats. Rat adrenal 3β-hydroxysteroid dehydrogenase/isomerase (3-HSD), 21-hydroxylase (21-OH) and 11-hydroxylase (11-OH) activities decreased with increasing RU486 doses, with 21-OH and 11-OH being most severely affected. Monkey adrenal 3-HSD, 21-OH, 11-OH, 1 7-hydroxylase and 17,20-desmolase similarly decreased in the presence of increasing in vitro concentrations of RU486. Taken together, these results suggest that RU486 directly inhibits adrenal steroidogenesis, with a locus of action at several key enzymatic steps in the glucocorticoid pathway. This steroidogenic blockade may account for the observed decreases in glucocorticoids during RU486 treatment.

Lynette K Nieman, Developmental Endocrinology Branch, NICHD, Building 10, Room 10N262, NIH, Bethesda, MD 20892, USA
Low-dose interleukin 1 and tumor necrosis factor individually stimulate insulin release but in combination cause suppression
Authors: Mehta Vivek K , Hao Wei , Brooks-Worrell Barbara M , Palmer Jerry P
Published: December 2008

Mehta VK, Hao W, Brooks-Worrell BM, Palmer JP. Low-dose interleukin 1 and tumor necrosis factor individually stimulate insulin release but in combination cause suppression. Eur J Endocrinol 1994;130:208–14. ISSN 0804–4643

The macrophage-derived cytokines interleukin 1 (IL-1) and tumor necrosis factor (TNF) have direct effects on pancreatic beta cells and have been hypothesized to play important roles in the autoimmune beta cell lesion of type I diabetes because of two major effects on beta cells: altered insulin secretion and beta cell cytotoxicity. High doses of IL-1 are cytotoxic to beta cells and strongly inhibit insulin release; high-dose IL-1 plus TNF acts synergistically to suppress further the insulin release. In contrast, we observed that the predominant effect of low-dose IL-1 and TNF when administered separately was the stimulation of insulin release. We therefore asked whether the combination of low-dose IL-1 plus TNF would act synergistically to stimulate or suppress insulin release. Studies were performed on cultured rat islets and both insulin release and cytotoxicity (51Cr release) were measured. After 2 days of culture, increasing doses of IL-1—25, 50, 75 and 100 ng/l—caused progressively increased cytotoxicity and impaired insulin release. In contrast, the lowest dose of IL-1 tested, 10 ng/l, increased insulin release but was still slightly cytotoxic. Tumor necrosis factor at doses of 10, 25, 62.5, 75 and 100 μg/l also was slightly cytotoxic but increased insulin release. The augmented insulin release declined progressively with increasing TNF dose. However the combination of insulin stimulatory doses of IL-1 (10 ng/l) and TNF (62.5 μg/l) suppressed insulin release. The effects of these two cytokines on insulin release demonstrated a similar pattern after 4 and 6 days of culture. Although both IL-1 and TNF are cytotoxic to cultured islets cells, the effects of these two cytokines on insulin release are markedly different: with IL-1 primarily suppressing and TNF increasing insulin release. In combination, IL-1 and TNF always inhibits insulin release. The lack of concordance between insulin release and cytotoxicity suggests that these cytokines may alter insulin release by at least two mechanisms, one dependent on and the other independent of cytotoxicity.

Jerry P Palmer, Veterans Affairs Medical Center, Endocrinology (111) ZB-21. 1660 S Columbian Way, Seattle, WA 98108, USA
Androgen manipulation and vasopressin binding in the rat brain and peripheral organs
Authors: Gao Xin , Phillips Paddy , Oldfield Brian , Trinder Deborah , Risvanis John , Stephenson Jayne , Johnston Colin
Published: December 2008

Gao X, Phillips P, Oldfield B, Trinder D, Risvanis J, Stephenson J, Johnston C. Androgen manipulation and vasopressin binding in the rat brain and peripheral organs. Eur J Endocrinol 1994;130:291–6. ISSN 0804–4643

It is now widely recognized that there is a sexual dimorphism in the development of arginine vasopressin (AVP) immunoreactivity in certain parts of the brain, and that changes in brain AVP immunoreactivity change with manipulation of androgen status. The aim of this experiment was to determine specifically any AVP receptor changes in response to manipulation of androgen levels using a selective V1 antagonist radioligand. Following castration, plasma testosterone levels fell and AVP immunoreactivity was reduced in the lateral septum and bed nucleus of the stria terminalis. With testosterone supplementation in castrated animals, the immunoreactivity in these regions was restored to a higher degree than in sham-operated animals. Central and peripheral V1 AVP receptor binding (as determined using the selective AVP V1 antagonist radioligand [125I](d(CH2)5,sarcosine7)AVP was not changed in any of the brain regions studied or in liver or kidney membranes from the three groups. This study demonstrates that there is no change in brain AVP receptor binding despite changes in regional AVP immunoreactivity in the brain, and excludes any confounding interaction with changes in oxytocin receptors.

P A Phillips, Department of Medicine, The University of Melbourne, Austin Hospital, Heidelberg, Victoria 3084, Australia
Effect of thyroid status on the oxidative capacity of Sertoli cells isolated from immature rat testis
Authors: Palmero S , Trucchi P , Prati M , Fugassa E , Lanni A , Goglia F
Published: December 2008

Palmero S, Trucchi P, Prati M, Fugassa E, Lanni A, Goglia F. Effect of thyroid status on the oxidative capacity of Sertoli cells isolated from immature rat testis. Eur J Endocrinol 1994;130:308–12. ISSN 0804–4643

Our previous studies indicate the Sertoli cell as a target for thyroid hormone action at testis level. In the present study we evaluated the effect of thyroid hormone on Sertoli cell oxidative capacity measured by specific cytochrome oxidase (COX) activity and intracellular adenosine triphosphate (ATP) content. Sertoli cells were isolated from 21-day-old rats. Hypothyroidism, induced from the day of birth by administration of 0.025% methimazole, was characterized by a severe delay of body and testis growth and resulted in a lower COX activity (−40%, p ≥ 0.01) and a lower ATP content (−35%, p ≥ 0.01) by isolated Sertoli cells. Administration of triiodothyronine (10 μg/100 g body wt on alternate days) to hypothryoid rats improved body and testis growth and restored both COX activity and ATP content. The presence of high-affinity, low-capacity binding sites for triiodothyronine in Sertoli cell mitochondria also was demonstrated. This study, unlike that carried out on the whole testis from adult rats, demonstrates that thyroid hormone affects the energy metabolism of Sertoli cells from midpubertal rat testes.

Silvio Palmero, Istituto di Fisiologia Generale, Università di Genova, Corso Europa 26,1-16132 Genova, Italy
Cortisol decreases 2[125I]iodomelatonin binding sites in the duck thymu
Authors: Poon AMS , Liu ZM , Tang F , Pang SF
Published: December 2008

Poon AMS, Liu ZM, Tang F, Pang SF. Cortisol decreases 2[125I]iodomelatonin binding sites in the duck thymus. Eur J Endocrinol 1994;130:320–4. ISSN 0804–4643

The immunosuppressive effect of chronic glucocorticoid treatment on 2[125I]iodomelatonin binding in the duck thymus was studied. Two-week-old ducks were injected intraperitoneally with either 1 mg of cortisol per day (experimental group) or an equivalent volume of vehicle (control group) in the middle of the light period for 7 days. 2[125I]Iodomelatonin binding assays were performed on thymic membranes. Cortisol injection reduced the body weight gain, size of the bursa of Fabricius and absolute weights of the primary lymphoid organs but had no effect on the spleen weights. The relative weights of the spleen were increased while those of the primary lymphoid organs were unchanged. The density of the thymus 2[125I]iodomelatonin binding sites was decreased while the affinity was not affected. The modulation of the thymic 2[125I]iodomelatonin binding sites by changes in the immune status of the duck suggests that these binding sites represent physiologically relevant melatonin receptors and that melatonin exerts its action on the lymphoid tissues directly. Our findings support the hypothesis that the thymus is the target site for the immunomodulatory interactions between the pineal melatonin and the adrenal steroids. A possible inhibitory influence of adrenal steroids on the immuno-enhancing effect of melatonin is also suggested.

AMS Poon, University of Hong Kong, 5 Sassoon Rd, Hong Kong
Ketoconazole therapy: hormonal and clinical effects in non-tumoral hyperandrogenism
Authors: Vidal-Puig Antonio J , Muñoz-Torres Manuel , Jódar-Gimeno Esteban , García-Calvente Carlos J , Lardelli P , Ruiz-Requena María E , Escobar-Jiménez Fernando
Published: December 2008

Vidal-Puig AJ, Muñoz-Torres M, Jódar-Gimeno E, García-Calvente CJ, Lardelli P, Ruiz-Requena ME, Escobar-Jiménez F. Ketoconazole therapy: hormonal and clinical effects in non-tumoral hyperandrogenism. Eur J Endocrinol 1994;130:333–8. ISSN 0804–4643.

The aim of this study was to assess the usefulness of ketoconazole as a therapeutic alternative to polycystic ovary syndrome. The study group comprised 37 women with signs of hyperandrogenism (hirsutism, acne) and oligomenorrhea. A low dose (400 mg/day) of ketoconazole was tested in a 9-month prospective clinical study. Clinical response (Ferriman & Gallway score, acne) and modifications in hormone pattern (luteinizing hormone, follicle-stimulating hormone, estradiol, testosterone, prolactin, 17-hydroxy-progesterone, androstenedione, steroid hormone-binding globulin, dehydroepiandrosterone sulfate, cortisol, adrenocorticotropin (ACTH) and free testosterone index) were measured, and ACTH stimulation tests were performed. Tolerance and side-effects also were assessed. After 9 months of ketoconazole treatment, the patients' Ferriman & Gallway scores (18.26 ± 4.6 vs 12.4 ± 4.1; p < 0.001) and acne had improved markedly. Hormone patterns also became more favorable, with decreases in androgenic steroids (testosterone, androstenedione, free testosterone index and dehydroepiandrosterone sulfate; p < 0.01) and increases in estradiol (p < 0.01). Basal cortisol levels and cortisol after ACTH stimulation were not changed significantly, remaining within the reference range. Increases in ACTH were observed only in the 3rd month (p < 0.01). Initial levels of androgenic steroids were correlated inversely with their percentage decrease in successive samplings. Decreases in adrenal androgenic steroids were associated with an increase in steroid hormone-binding globulin. The side-effects of treatment, although not severe, caused some discomfort and led to a high drop-out rate (30%). Our results suggest that low doses of ketoconazole (400 mg/day) are an alternative therapy for non-tumoral hyperandrogenism, although the bothersome side-effects, which require close monitoring and maximal patient compliance, make this treatment advisable only in selected patients.

Manuel Muñoz-Torres, Plaza Isabel la Católica no. 2, E-18009, Granada, Spain
Lack of vasoactive intestinal peptide-releasing property in prolactin cells from ovariectomized rats: contribution of post-transductional impairments
Authors: Pizzi Marina , Arrighi Virginia , Galli Paola , Memo Maurizio , Spano Pier Franco
Published: December 2008

Pizzi M, Arrighi V, Galli P, Memo M, Spano PF. Lack of vasoactive intestinal peptide-releasing property in prolactin cells from ovariectomized rats: contribution of post-transductional impairments. Eur J Endocrinol 1994;130:361–5. ISSN 0804–4643

We have demonstrated recently that in menopausal women and in ovariectomized rats the deficiency of circulating oestrogens impairs vasoactive intestinal peptide (VIP) efficacy in stimulating prolactin (PRL) release. The present study was designed to investigate whether the lack of VIP-induced PRL release after ovariectomy is a consequence of a defect at the receptor-transductional or post-transductional level. For this purpose we evaluated the VIP receptor function, by measuring VIP-stimulated cyclic adenosine monophosphate (AMP) formation, and the efficacy of the cyclic AMP-dependent PRL release in pituitary cells from control and ovariectomized animals. We observed that VIP induced a significantly higher stimulation of adenylate cyclase in pituitary homogenates from ovariectomized rats than in those from control animals. This effect appeared to be linked to an increased efficiency of the Gs coupling protein, because superimposable results were obtained by using the non-hydrolysable guanosine triphosphate (GTP) analogue, 5-guanylylimidodiphosphate. On the contrary, the cyclic AMP analogue, 8-Br-cAMP, that potently stimulated PRL release from control pituitary cells was completely ineffective in cells from ovariectomized rats. The present data indicate that in PRL-secreting cells from ovariectomized rats a defect in the post-transductional mechanism that couples the VIP receptor to PRL secretion, rather than a reduction of receptor function, possibly accounts for the lack of VIP efficacy.

Marina Pizzi, Dept. Biomed. Sci. & Biotech., School of Medicine, Via Valsabbina 19, 25123 Brescia, Italy
Brain Lys-aminopeptidase activity. Changes during cycle and pregnancy
Authors: de Gandarias Juan M , Irazusta Jon , Fernández David , Echevarría Enrique , Casis Luis
Published: December 2008

De Gandarias JM, Irazusta J, Fernández D, Echevarría E, Casis L. Brain Lys-aminopeptidase activity. Changes during cycle and pregnancy. Eur J Endocrinol 1994;130:373–7. ISSN 0804–4643

Lys-aminopeptidase activity levels during the estrous cycle (estrous and proestrous, in the morning and afternoon) and the pregnancy (2nd, 7th, 14th and 20th day postinsemination and the parturition day), in several areas of the rat brain, were studied in this research. The selected brain regions were the frontal, parietal and occipital cortices, olphactory bulbus, thalamus, hypothalamus, hippocampus, amygdala, striatum and pituitary gland. The most significant changes were shown in the hypothalamus and the pituitary gland. Thus, in these areas, the higher cyclic enzyme levels were found in the proestrous stage. During pregnancy, there was a rise on the 7th and 14th days, with a decrease on the 20th day. Also, similar changes in the occipital cortex, striatum, hippocampus and amygdala were appreciated, but fewer than those observed in the hypothalamus and the pituitary. In conclusion, the activity of the aminopeptidase under study fluctuates during the estrous cycle and during pregnancy, as well as in the hypothalamic–pituitary axis and also in several extrahypothalamic areas of the rat brain.

Luis Casis Saenz, Department of Physiology, Medical School, University of the Basque Country, PO Box 699, Bilbao, Spain
Effects of fluoride on human bone cells in vitro: differences in responsiveness between stromal osteoblast precursors and mature osteoblasts
Authors: Kassem Moustapha , Mosekilde Leif , Eriksen Erik F
Published: December 2008

Kassem M, Mosekilde L, Eriksen EF. Effects of fluoride on human bone cells in vitro: differences in responsiveness between stromal osteoblast precursors and mature osteoblasts. Eur J Endocrinol 1994;130:381–6. ISSN 0804–4643

The cellular effects of sodium fluoride (NaF) on human bone cells in vitro have been variable and dependent on the culture system used. Variability could be attributed to differences in responsiveness to NaF among different populations of cells at various stages of differentiation in the osteoblastic lineage. In this study we compared the effects of NaF in serum-free medium on cultures of more differentiated human osteoblast-like (hOB) cells derived from trabecular bone explants and on osteoblast committed precursors derived from human bone marrow, i.e. human marrow stromal osteoblast-like (hMS(OB)) cells. Sodium fluoride (10−5 mol/l) increased proliferation of hMS(OB) cells (p<0.05, N = 10) but was not mitogenic to hOB cells (p>0.05, N= 10). Alkaline phosphatase (AP) production increased in both hMS(OB) (p<0.05, N=9) and hOB cells (p<0.05, N=9). No significant effects on procollagen type I propeptide production were obtained in either culture. In the presence of 1,25-dihydroxycholecalciferol (10−9 mol/l), NaF enhanced alkaline phosphatase (p<0.05, N=8), procollagen type I propeptide (p<0.05, N=7) and osteocalcin (p<0.05, N=7) production by hMS(OB) cells but not by hOB cells. Our results suggest that osteoblast precursors are more sensitive to NaF action than mature osteoblasts and that the in vivo effects of NaF on bone formation may be mediated by stimulating proliferation and differentiation of committed osteoblast precursors in bone marrow.

M Kassem, Mayo Clinic, Endocrine Research Unit, W-Joseph 5-164, Rochester, MN 55904, USA
Interactions of insulin-like growth factor I with dexamethasone on trabecular bone density and mineral metabolism in rats
Authors: Binz Katharina , Schmid Christoph , Bouillon Roger , Froesch E Rudolf , Jürgensen Kay , Hunziker Ernst B
Published: December 2008

Binz K, Schmid C, Bouillon R, Froesch ER, Jürgensen K, Hunziker EB. Interactions of insulin-like growth factor I with dexamethasone on trabecular bone density and mineral metabolism in rats. Eur J Endocrinol 1994;130:387–93. ISSN 0804–4643

Glucocorticoid treatment causes osteoporosis and growth retardation in humans. Insulin-like growth factor I (IGF-I) stimulates differentiation and replication of cultured osteoblast-like cells and induces longitudinal bone growth in IGF-I-deficient rats. We investigated the influence of subcutaneously infused IGF-I on bone and mineral metabolism of male rats treated with a high dose of dexamethasone. Dexamethasone was added to the drinking water in a concentration of 1 mg/l. After 30 days of dexamethasone treatment, recombinant human IGF-I (300 μg/day) or solvent was infused sc by osmotic minipumps for 21 days while dexamethasone was continued. Age-matched untreated male rats served as healthy controls. Dexamethasone-treated rats lost weight. Their IGF-I levels were decreased to 36% of healthy controls. Infusion of IGF-I resulted in an increase in IGF-I serum levels (582% compared to healthy controls) and allowed some weight gain. Osteocalcin and calcitriol levels were markedly decreased in dexamethasone-treated rats and were not influenced significantly by IGF-I infusion. In contrast, IGF-I treatment restored the free calcitriol concentration (molar ratio of calcitriol to vitamin D-binding protein) towards normal. Furthermore, infusion of IGF-I partially corrected the dexamethasone-induced hyperinsulinemia. Histomorphometric analysis revealed no difference in vertebral trabecular bone density (i.e. growth-independent bone remodeling) between the three groups. In contrast, mean trabecular bone density in tibial metaphyses was increased markedly by dexamethasone, presumably due to osteoclast inhibition. Insulin-like growth factor I infusion did not significantly influence these structural metaphyseal bone parameters. We conclude that IGF I-infusion in male rats treated with high doses of dexamethasone reduces insulin resistance and restores calcitriol production but not osteoblast function or responsiveness to calcitriol.

K Binz, Division de Diabétologie, Hôpital Cantonal Universitaire, 1211 Geneva, Switzerland
Responsiveness to corticotropin-releasing hormone and vasopressin in canine Cushing's syndrome
Authors: van Wijk Petra A , Rijnberk Ad , Croughs Ronald JM , Wolfswinkel Jeannette , Selman Paulus J , Mol Jan A
Published: December 2008

Van Wijk PA, Rijnberk A, Croughs RJM, Wolfswinkel J, Selman PJ, Mol JA. Responsiveness to corticotropin-releasing hormone and vasopressin in canine Cushing's syndrome. Eur J Endocrinol 1994;130:410–16. ISSN 0804–4643

Corticotropin-releasing hormone (CRH) and vasopressin are the most important hypothalamic factors regulating adrenocorticotropic hormone (ACTH) secretion. In this study we have investigated the responsiveness of the pituitary–adrenocortical axis to intravenous administration of CRH or lysine vasopressin (LVP) in 16 control dogs, 22 dogs with pituitary-dependent hyperadrenocorticism and five dogs with hyperadrenocorticism due to an adrenocortical tumor, using doses of CRH and LVP that caused equivalent ACTH responses in the control dogs. After CRH administration, the increment in plasma ACTH was significantly (p < 0.05) lower in dogs with pituitary-dependent hyperadrenocorticism (221 ± 53 ng/l) than that in control dogs (279 ± ng/l). In the dogs with pituitary-dependent hyperadrenocorticism, the relative increases in ACTH after CRH were significantly (p < 0.05) lower than those after LVP. Despite the absence of an increase in ACTH following LVP administration in dogs with hyperadrenocorticism due to an adrenocortical tumor, there was a significant increase in plasma cortisol, the increment (790 ±238 nmol/l) being not statistically different from that in the control dogs (412 ± 37 nmol/l). We conclude that in spite of the changes inherent to pituitary-dependent hyperadrenocorticism, i.e. neoplastic transformation of corticotropic cells and hypercortisolism, there is persistence of responsiveness to hypophysiotropic hormones. The ACTH secretion by corticotropic cells in pituitary-dependent hyperadrenocorticism was relatively less sensitive to stimulation with CRH than with LVP. Adrenocortical tumors develop an aberrant sensitivity to LVP.

A Rijnberk, Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.154, 3508 TD, Utrecht, The Netherlands
Effects of anti-prolactin autoantibodies on serum prolactin measurements
Authors: Hattori Naoki , Ikekubo Katsuji , Ishihara Takashi , Moridera Kunisaburo , Hino Megumu , Kurahachi Hiroyuki
Published: December 2008

Hattori N, Ikekubo K, Ishihara T, Moridera K, Hino M, Kurahachi H. Effects of anti-prolactin autoantibodies on serum prolactin measurements. Eur J Endocrinol 1994:130:434–7. ISSN 0804–4643

The influence of anti-PRL autoantibodies on PRL measurements determined by immunoassays was investigated in 10 patients with anti-PRL autoantibodies. Four different immunoassay systems (two double-antibody radioimmunoassays (RIAs), a single-antibody RIA and an immunoradiometric assay (IRMA)) were examined. Total and free PRL were extracted from sera by precipitating γ-globulin with polyethylene glycol with and without acidification, respectively. PRL values determined by direct measurement were compared with total PRL values. The proportion of free to total PRL levels determined by each immunoassay in sera with anti-PRL autoantibodies was significantly lower than in control sera. Values obtained by direct measurement of PRL (a routine assay procedure) in control sera were similar to total PRL values, whereas in sera with anti-PRL autoantibodies the values varied from one immunoassay to the other. In sera with anti-PRL autoantibodies, double-antibody RIA I, RIA 2 and single-antibody RIA 3 yielded values lower for PRL than for total PRL (52 ±15% in RIA 1, 40±8.8% in RIA 2.40±14% in RIA 3), while PRL levels determined by IRMA were not significantly different (112 ±14%). Immunoglobulin G purified from serum with anti-PRL autoantibodies dosedependently decreased the recovery of PRL assayed by the double-antibody technique, while it did not affect that by IRMA. These data suggest that the presence of anti-PRL autoantibodies gives variable results depending on the immunoassays used. It is noteworthy that anti-PRL autoantibodies do not cause falsely high PRL values, as in the case of antithyroid hormone autoantibodies, rather they cause an underestimate, when a double-antibody RIA, a routine method for PRL measurement, is used.

Naoki Hattori, Department of Endocrinology. Kobe City General Hospital, 4-6 Minatojima Nakamachi, Chuoku, Kobe 650, Japan
Correlation of the antibody titers with serum prolactin levels and their clinical course in patients with anti-prolactin autoantibody
Authors: Hattori Naoki , Ikekubo Katsuji , Ishihara Takashi , Moridera Kunisaburo , Hino Megumu , Kurahachi Hiroyuki
Published: December 2008

Hattori N, Ikekubo K, Ishihara T, Moridera K, Hino M, Kurahachi H. Correlation of the antibody titers with serum prolactin levels and their clinical course in patients with anti-prolactin autoantibody. Eur J Endocrinol 1994;130:438–45. ISSN 0804–4643

Patients with anti-prolactin (PRL) autoantibody were surveyed among 208 patients with hyperprolactinemia (PRL ≥ 30 μg/l) and 228 subjects with normal PRL levels, and the relationship of the antibody titers with serum PRL levels and their clinical course were studied. Diagnosis of possessing the anti-PRL autoantibody was based on the polyethylene glycol method, displacement of the binding of [125I]PRL with the serum by unlabeled PRL and the binding of PRL to protein G, the affinity gel for immunoglobulin G. Prolactin was measured by an immunoradiometric assay that we found was not affected by the anti-PRL autoantibody. A significantly high frequency of anti-PRL autoantibody in patients with idiopathic hyperprolactinemia (16%) and a positive correlation between titers of the autoantibody and serum PRL levels (r = 0.74, p < 0.01) may indicate that the anti-PRL autoantibody itself is another cause of hyperprolactinemia, probably owing to the delayed clearance of PRL. Most patients with anti-PRL autoantibody lacked the clinical symptoms of hyperprolactinemia, such as amenorrhea and galactorrhea, and spontaneous pregnancy occurred despite the marked hyperprolactinemic state, indicating that the biological activity of PRL was attenuated by the autoantibody. In addition, PRL levels and the titers of anti-PRL autoantibody were not changed significantly during the observation period of up to 5 years without any medical intervention. These results suggest that the anti-PRL autoantibody itself is one of the causes of hyperprolactinemia and that medical intervention is unnecessary for this type of hyperprolactinemia.

Naoki Hattori, Department of Endocrinology, Kobe City General Hospital, 4–6 Minatojima Nakamachi, Chuo-ku, Kobe 650, Japan
Decreased chemotaxis of neutrophils in acromegaly and hyperprolactinemia
Authors: Fornari M Cecilia , Palacios M Fernanda , Diez Roberto A , Intebi Alberto D
Published: December 2008

Cecilia Fornari M, Fernanda Palacios M, Diez RA, Intebi AD. Decreased chemotaxis of neutrophils in acromegaly and hyperprolactinemia, Eur J Endocrinol 1994;130:463–8. ISSN 0804–4643

Both growth hormone (GH) and prolactin (PRL) modulate immune responses in vitro. We studied chemotaxis under agarose of polymorphonuclear cells from patients with acromegaly or hyperprolactinemia. Polymorphonuclear cells were purified by dextran sedimentation and subjected to stimulation with N-formylmethionyl-phenylalanine, The results showed a decrease in both directed migration (acromegaly: 971 ± 155 μm, hyperpolactinemia: 1123 ± 137 μm, expressed as mean± sem) and spontaneous migration (acromegaly: 270 ± 77 μm: hyperpolactinemia: 298 ± 77 μm) when compared to similar features from normal controls (directed migration: 2019 ± 99 μm: spontaneous migration: 590 ± 49 μm) and from patients with non-GH/PRL-secreting pituitary tumours (directed migration: 1633 ± 282 μm: spontaneous migration: 562 ± 116 μm), suggesting that this defect is selective for acromegaly and hyperprolactinemia. Our results point to a putative direct or indirect effect of GH and PRL on polymorphonuclear cell chemotaxis.

AD Intebi, Endocrinologia, Dpto de Medicina Interna, Hospital "Juan A Fernandez", Cerviño 3356 (125), Buenos Aires, Argentina
False negative results observed in anti-thyroid peroxidase autoantibody determination by competitive radioimmunoassays using monoclonal antibodies
Authors: Mariotti Stefano , Barbesino Giuseppe , Caturegli Patrizio , Atzeni Francesca , Manetti Luca , Marino Michele , Grasso Lucia , Velluzzi Fernanda , Loviselli Andrea , Pinchera Aldo , Martino Enio
Published: December 2008

Mariotti S, Barbesino G, Caturegli P, Atzeni F, Manetti L, Marinò M, Grasso L, Velluzzi F, Loviselli A, Pinchera A, Martino E. False negative results observed in anti-thyroid peroxidase autoantibody determination by competitive radioimmunoassays using monoclonal antibodies. Eur J Endocrinol 1994;130:552–8. ISSN 0804–4643

Objective: Anti-thyroid peroxidase autoantibody (anti-TPO) and anti-thyroid microsomal antibody (anti-M) are strictly related, but discrepancies are sometimes observed. The aim of this study was to assess the incidence and to identify the causes of these discrepancies. Design and antibody measurements: Anti-M by passive hemagglutination and anti-TPO by two competitive monoclonal antibody-assisted radioimmunoassays (RIA-1 and RIA-2) were measured in 10 103 sera from 4232 subjects (663 male, 3569 female) screened for thyroid disease. Results: Anti-TPO and anti-M correlated quite well (r = 0.7 and p < 0.0001 by RIA-1; r = 0.74 and p < 0.0001 by RIA-2), with discrepancies mostly limited to sera with low antibody titers. After exclusion of the latter samples, anti-TPO were detected in only 79 (1.4%) out of 5317 anti-M negative sera, but were undetectable in a more consistent proportion (130/2880 = 4.5%) of sera from patients with autoimmune thyroid disease and positive anti-M. In 61 sera of the latter group, anti-TPO was measured by a non-competitive RIA (RIA-3). Forty-one (67.7%) were positive by RIA-3, suggesting the presence of anti-TPO not competing with the monoclonal antibodies of RIA-1 and RIA-2. The remaining 20 sera had undetectable anti-TPO also by RIA-3. Nineteen (95%) of these sera had positive anti-thyroglobulin (anti-Tg) autoantibody and preincubation with thyroglobulin inhibited the agglutination reaction of anti-M tests. Conclusion: Anti-TPO by competitive monoclonal antibody-assisted RIA is negative in a minority of sera of patients with autoimmune thyroid disease and positive anti-M. This could be accounted for by anti-Tg producing false positives in the anti-M assay and by a subset of anti-TPO not competing with the monoclonal antibodies in the RIA. When autoimmune thyroid disease is suspected on clinical grounds, a negative anti-TPO test with a competitive RIA should be confirmed always by a non-competitive assay.

Stefano Mariotti. Institute of Endocrinology. University of Pisa, Viale del Tirreno 64,1-56018 Tirrenia-Pisa, Italy
Serum carboxy-terminal propeptide of human type I procollagen in patients with primary hyperparathyroidism: studies in basal conditions and after parathyroid surgery
Authors: Minisola Salvatore , Romagnoli Elisabetta , Scarnecchia Liliana , Rosso Rossana , Pacitti Maria T , Scarda Antonella , Mazzuoli Gianfranco
Published: December 2008

Minisola S, Romagnoli E, Scarnecchia L, Rosso R, Pacitti MT, Scarda A, Mazzuoli G. Serum carboxyterminal propeptide of human type I procollagen in patients with primary hyperparathyroidism: studies in basal conditions and after parathyroid surgery. Eur I Endocrinol 1994;130:587–91. ISSN 0804-4643

This study was carried out in order to evaluate serum carboxy-terminal propeptide of human type I procollagen (PICP) in patients with primary hyperparathyroidism and to examine its changes following parathyroidectomy. Seventeen patients (four males and 13 famels, aged 53.8 ± 3.1 sem years) were studied in basal conditions; six patients also were investigated after successful parathyroid surgery. Mean serum PICP values of patients with primary hyperparathyroidism (194.5 ± 27 sem μg/l) were significantly higher (p < 0.001) with respect to those found in normal subjects. However, deviations from the norm (Z score values) were significantly less with respect to deviations of serum osteocalcin, alkaline phosphatase and urinary hydroxyproline/creatinine ratio. Following parathyroidectomy, it was possible to observe a discrepancy between markers of bone resorption and those of bone formation. The former tend to decrease, while the latter either do not show any significant change (serum alkaline phosphatase and serum osteocalcin) or increase (serum procollagen). The results of our investigation indicate that in basal conditions the assay of serum procollagen may be of clinical value but it would be better to use it in combination with other biomarkers of skeletal remodelling. The results obtained after parathyroidectomy are the opposite of those obtained following parathyroid hormone infusion and should be ascribed to the effect of acute hormone deficiency on collagen synthesis. The positive biochemical uncoupling following surgery might lend support to the rise of bone mineral density consistently reported in the first few months following parathyroidectomy.

S Minisola, Istituto di II Clinical Medica, Policlinico Umberto I, Via del Policlinico 155, 00161 Rome, Italy
Exogenous free iodotyrosine inhibits iodide transport through the sequential intracellular events
Authors: Nasu Michiyo , Sugawara Masahiro
Published: December 2008

Nasu M, Sugawara M. Exogenous free iodotyrosine inhibits iodide transport through the sequential intracellular events. Eur J Endocrinol 1944;130:601–7. ISSN 0804–4643

We describe a new function of exogenous iodotyrosine as a regulator of iodide transport. Porcine thyroid follicles in culture were preincubated with 0–20 μmol/l monoiodotyrosine or diiodotyrosine (DIT) in the presence of bovine thyrotropin (TSH) for 24 h; these iodotyrosines inhibited iodide uptake in a dose–response manner. Extracellular [125I]DIT was actively transported to the thyroid follicle in the presence of TSH or (Bu)2cAMP. Inhibition of iodide uptake by iodotyrosine required preincubation with iodotyrosine in the presence of TSH; without TSH, iodotyrosine was ineffective. Follicles preincubated with DIT for 24 h inhibited TSH-mediated cAMP production, which is an important signal for iodide transport. Inhibition of iodide uptake and cAMP generation by iodotyrosine was negated characteristically by 3-nitro-l-tyrosine, an inhibitor of iodotyrosine deiodinase, or by methimazole, an inhibitor of thyroid peroxidase. Our findings suggest that iodotyrosine regulates iodide transport through the following sequential intracellular events: TSH-dependent iodotyrosine transport into the thyroid cell; deiodination of iodotyrosine and release in iodide; iodine organification by the peroxidase system; inhibition of cAMP generation by organified iodine; and inhibition of iodide transport. Thus, exogenous iodotyrosine can serve as an inhibitor of thyroid hormone formation only when TSH is present

M Sugawara, Wadsworth VA Hospital (11 IM), Wilshire and Sawtelle Blvds, Los Angeles, CA 90073, USA
Pancreatic and islet blood flow in F1-hybrids of the non-insulin-dependent diabetic GK-Wistar rat
Authors: Svensson Annika M , Abdel-Halim Samy M , Efendic Suad , Jansson Leif , Östenson Claes-Göran
Published: December 2008

Svensson AM, Abdel-Halim SM, Efendic S, Jansson L, Östenson C-G. Pancreatic and islet blood flow in F1 -hybrids of the non-insulin-dependent diabetic GK-Wistar rat. Eur J Endocrinol 1994:130:612–16. ISSN 0804–4643

Previous studies have indicated that various conditions under which an increased functional load is posed on the pancreatic islets, e.g. partial pancreatectomy and continuous glucose infusions, may influence the microcirculation of the pancreas. To investigate further the effects of elevated functional demand on the islets, the blood perfusion of the whole pancreas and the pancreatic islets was measured with a microsphere technique in an animal model presenting impaired glucose tolerance and mild hyperglycemia, namely F 1-hybrids of the spontaneously non-insulin-dependent diabetic GK-Wistar rat. Normal Wistar rats served as controls. All hybrids had a pathological intraperitoneal glucose tolerance test 1 week before the blood flow measurements, which were performed in 10–12-week-old rats. Both the whole pancreatic and the islet blood flows were increased in the hybrids compared to controls. The fractional islet blood flow, i.e. the fraction of whole pancreatic blood flow diverted through the islets, also was increased in the hybrid rats (12.6 ±0.6% vs 9.8 ±0.5% in controls, p <0.01). A bilateral abdominal vagotomy performed 30 min before the blood flow measurement markedly decreased the blood flow values of the islets and the whole pancreas in both groups of rats. After vagotomy, the islet blood flow in the hybrid rats was similar to that of the vagotomized control animals (8.2 ± 0.8 and 7.5 ± 1.4%, respectively). It is concluded that the increased pancreatic and islet blood perfusion observed in F 1-hybrids of the GK-Wistar rat depends on a mechanism mediated by the vagus nerve.

Annika M Svensson, Department of Medical Cell Biology, Biomedical Centre, PO Box 571, S-75123 Uppsala, Sweden