bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased expression of estrogen receptor beta in human uterine smooth muscle at term
Authors: Wu JJ , Geimonen E , Andersen J
Published: January 2005

Expression of the cx43 gene for the gap junction protein, connexin43 (Cx43), through activator protein (AP)-1 activity has been shown to be inhibited in human primary myometrial cultures pretreated with estrogen. In the present study, the primary myometrial cultures were shown to express predominantly ERbeta, a subtype of estrogen receptor that inhibits AP-1 activity when bound to agonists. ERbeta levels were decreased in the primary myometrial cultures after treatment with the phorbol ester, 12-O-tetradecanolyl-13 acetate, to stimulate AP-1 activity, and this effect is inhibited if cells were pretreated with estrogen. Two isoforms of ERbeta were found in primary myometrial and leiomyoma cultured cells. Immunoblot and RT-PCR analyses indicated that ERbeta expression was increased in human term myometrial tissue compared with non-pregnancy tissue. Immunohistochemistry localized ERbeta to the nucleus in cells of term myometrial tissue samples that had high ERbeta expression. ERbeta was increased in term tissue in which Cx43 protein levels were low. In myometrial tissue in which Cx43 protein levels are greatest (e.g. during active labor), ERbeta was barely detectable. Only low levels of ERbeta were detected in non-pregnancy myometrial and leiomyoma tissues, and the lowest levels were found in tissues from mid cycle. In contrast, ERalpha was highly detectable in the non-pregnancy myometrial and leiomyoma tissues, but not in term myometrial tissue samples. This work indicates there is a dramatic switch from ERalpha to ERbeta expression in the myometrium during pregnancy. The results suggest that, during gestation, myometrial ERbeta may inhibit AP-1 activity and thus block induction of the cx43 gene and other labor-associated genes. Labor may ensue after a loss of myometrial ERbeta expression.
Medical therapy of Graves' disease: effect on remission rates of methimazole alone and in combination with triiodothyronine
Authors: Raber W , Kmen E , Waldhausl W , Vierhapper H
Published: January 2005

In a prospective, randomized study of 135 newly diagnosed patients with hyperthyroidism due to Graves' disease we compared the effect on remission rates of additional triiodothyronine (T3) with conventional antithyroid drug therapy. To this end 114 patients were followed for at least 12 months (15.7+/-4.9, mean+/-s.d.) after the discontinuation of any therapy. After return of thyroid function to normal (8.5+/-7.4 weeks, mean+/-s.d.) patients were maintained on antithyroid medication for 9.0+/-2.5 months. They were then randomly assigned to one of three groups: group 1 (n=44) stopped methimazole, groups 2 (n=39) and 3 (n=31) continued with exogenous T3 (not exceeding 75 microgram/day in any patient) for a further 6 months either with (group 2) or without (group 3) a fixed dose of 10mg methimazole daily. The T3 dose was kept variable to keep TSH suppressed (<0. 1mU/l), which could be achieved in 82% of patients on 100% of their monthly visits. No serious side-effect requiring the discontinuation of the study occurred in any patient. Total T3, TSH-receptor antibodies and some previously suggested potential predictors of relapse including thyroid size by ultrasound, 24h urinary iodine excretion, history of cigarette smoking and ophthalmopathy were determined at the outset of the study and subsequently every 6 months (and total T3 every 4 weeks). No significant difference (P>0.05, Chi square) was seen in relapse of hyperthyroidism after a mean follow-up of 16 months (range: 12-31 months; groups 1:52%, 2:44% and 3:42%) in an area of low-to-moderate iodine intake (prevalence of 24h urinary iodine excretion <100 microgram/24h: 17 and 25% at two different measurements respectively). Concomitantly, no predictor of recurrence of disease could be identified, irrespective of treatment modality.
MEN1 gene mutation analysis in Italian patients with multiple endocrine neoplasia type 1
Authors: Morelli A , Falchetti A , Martineti V , Becherini L , Mark M , Friedman E , Brandi ML
Published: January 2005

Multiple endocrine neoplasia type 1 (MEN 1) is a familial syndrome characterized by parathyroid, enteropancreatic and pituitary tumors. The gene responsible for this syndrome is localized at chromosomal 11q13 region and DNA markers from this region cosegregate with the disease. The recent identification of the MEN1 gene, encoding for a protein termed menin of 610 amino acids, allowed mutational screening to be performed both in affected families and sporadic cases. To date many different heterozygous mutations, spreading across all the encoding sequence, have been identified in MEN 1 patients with no apparent mutational hot spots or genotype-phenotype correlation. To analyze the genetic alterations of the MEN1 gene occurring in Italian patients we performed mutational screening by Denaturant Gradient Gel Electrophoresis followed by sequencing of exons 2-10 of the MEN1 gene in 27 Italian MEN 1 families and in five sporadic cases. We identified 17 different heterozygous mutations in 60% of analyzed cases. Twelve of these mutations are novel. Two mutations each occurred twice in unrelated families but no evidence of genotype-phenotype correlation can be established for these families. The extension of genetic diagnosis to asymptomatic family members allowed the identification of 10 MEN1 mutant gene carriers, one newly described and nine previously detected by linkage analysis with DNA markers from the 11q13 region. Our findings add new information to the diversity of mutations occurring in the MEN1 gene and confirm that the mutational screening of MEN 1 is a useful approach to detect individuals at higher risk of developing MEN 1-associated tumors.
Plasma leptin concentrations in postmenopausal women with osteoporosis
Authors: Odabasi E , Ozata M , Turan M , Bingol N , Yonem A , Cakir B , Kutlu M , Ozdemir IC
Published: January 2005

BACKGROUND: The obese are usually protected against osteoporosis and have increased bone mineral density and plasma leptin concentrations. A recent in vitro study demonstrated that leptin acts on human marrow stromal cells to enhance differentiation to osteoblasts, suggesting an influence of leptin on bone mass. However, little is known about the relationship between plasma leptin and bone mass in postmenopausal women with osteoporosis. OBJECTIVE: To investigate plasma leptin concentrations in postmenopausal women with osteoporosis to improve the understanding of the role of leptin in determining bone mass. METHODS: Fifty postmenopausal women with osteoporosis (ages 61.18+/-6.51 years; body mass index (BMI) 28. 91+/-3.44kg/m(2), mean+/-s.d.) and 30 age- and BMI-matched healthy postmenopausal women were included in the study. Bone mineral densities (BMD) were measured by dual energy X-ray absorptiometry. Plasma leptin concentrations were determined using an immunoradiometric assay. RESULTS: The median spine BMD value in the patient group (0.695+/-8.26g/cm(2), median+/-s.e.m.) was significantly lower than that in the control group (1.006+/-1. 29g/cm(2), median+/-s.e.m.; z=-7.454, P<0.001). The median plasma leptin concentration in the patient group (18.70+/-1.78ng/ml, median+/-s.e.m.) was not significantly different from that in the control group (22.35+/-2.20ng/ml, median+/-s.e.m.; z=-1.630, P=0. 103). Plasma leptin concentrations were correlated with BMI in both groups (r(s)=0.394, P=0.031 in controls and r(s)=0.404, P=0.004 in the patient group). There was no correlation between plasma leptin concentrations and BMD values in controls (r(s)=-0.107, P=0.575) but a weak correlation was observed in the patient group (r(s)=0.285, P=0.045). CONCLUSION: Our data suggest that circulating plasma leptin does not have a significant direct influence on bone mass in postmenopausal women.
Cold exposure inhibits leptin secretion in vitro by a direct and non-specific action on adipose tissue
Authors: Peino R , Pineiro V , Gualillo O , Menendez C , Brenlla J , Casabiell X , Dieguez C , Casanueva FF
Published: January 2005

OBJECTIVE: Leptin secretion is reduced by low temperatures in experimental animals, and this effect has been explained as an adaptive mechanism to cold environments. This study investigated the in vitro effects of cold exposure on human white adipose tissue. DESIGN: To understand whether the low temperature action is a direct or a mediated effect, leptin secretion was assessed in vitro in human omental adipose tissue incubated at varied temperatures, from 38 donors. As an internal control, the effect of reduced temperatures on in vitro GH secretion by GH3 cells was assessed. METHODS: Measurement of hormones secretion was carried out with an RIA, while human ob gene mRNA expression was assessed with reverse transcription PCR. RESULTS: Compared with the standard temperature of 37 degrees C, leptin secretion by human adipose tissue was significantly (P<0.05) reduced when the incubations were carried out at 34.5 degrees C (41% inhibition), and 32 degrees C (68% inhibition), with no parallel changes in the ob mRNA expression. At these reduced temperatures, glucocorticoid-mediated leptin secretion was well preserved. When the effect of reduced temperatures was assessed on in vitro GH secretion, a superimposable reduction was observed. CONCLUSIONS: These results indicate: (i) that low temperatures reduce leptin secretion by acting directly on the adipose tissue and (ii) that the similar reduction in a hormone unrelated to energy metabolism, such as GH, suggests that the observed reduction is a mechanical perturbation of leptin secretion, which may be devoid of physiological implications.
Diagnostic efficiency of serum IGF-I, IGF-binding protein-3 (IGFBP-3), IGF-I/IGFBP-3 molar ratio and urinary GH measurements in the diagnosis of adult GH deficiency: importance of an appropriate reference population
Authors: Granada ML , Murillo J , Lucas A , Salinas I , Llopis MA , Castells I , Foz M , Sanmarti A
Published: January 2005

OBJECTIVE: To analyse the diagnostic role of serum IGF-I, IGF-binding protein-3 (IGFBP-3), IGF-I/IGFBP-3 molar ratio and urinary GH (uGH) excretion in adult GH deficiency (GHD). DESIGN: Twenty-seven adults (age range: 18-71 years) with severe GHD, defined by a peak GH response to an insulin tolerance test below 3microg/l in patients with at least one additional pituitary hypofunction. Reference values were established from a selected age- and body mass index-matched population (154 healthy adults grouped in four age groups). METHODS: IGF-I and IGFBP-3 were measured by RIA (Nichols) and results expressed as standard deviation (s.d.) scores from our reference population and assay normative data (s.d. score Nichols). uGH was measured by IRMA. RESULTS: Within the control group, IGF-I, IGFBP-3, IGF-I/IGFBP-3 ratio standardisation regarding our control population and IGF-I with respect to the assay normative data resulted in disappearance of age-related differences. However, IGFBP-3 s.d. score Nichols resulted in mean values between +1.4 and +2.5 s.d. score. Greatest diagnostic efficiency was for IGF-I standardised with respect to our controls (97.2%), followed by s.d. score IGFBP-3 (92.9%). s.d. score IGF/IGFBP-3 ratio and uGH showed poor diagnostic efficiency. Any combination of at least two abnormal parameters raised specificity to 100%. IGF-I standardised with respect to assay reference (s.d. score Nichols) showed similar diagnostic value (95.0%) whereas IGFBP-3 showed low sensitivity (33. 3%). Within the GHD patients, those with three or more additional deficiencies had lower s.d. score IGF-I than those with only two or one. CONCLUSION: We underline the importance of an appropriate reference population for correct interpretation of GH secretion markers. Considering our results, specificity obtained with two simultaneous abnormal parameters when referred to an adequate reference population may add valuable information to alternative GH stimulation tests to confirm adult GHD.
Hypothalamic amenorrhea with normal body weight: ACTH, allopregnanolone and cortisol responses to corticotropin-releasing hormone test
Authors: Meczekalski B , Tonetti A , Monteleone P , Bernardi F , Luisi S , Stomati M , Luisi M , Petraglia F , Genazzani AR
Published: January 2005

OBJECTIVE: Hypothalamic amenorrhea (HA) is a functional disorder caused by disturbances in gonadotropin-releasing hormone (GnRH) pulsatility. The mechanism by which stress alters GnRH release is not well known. Recently, the role of corticotropin-releasing hormone (CRH) and neurosteroids in the pathophysiology of HA has been considered. The aim of the present study was to explore further the role of the hypothalamic-pituitary-adrenal axis in HA. DESIGN: We included 8 patients (aged 23.16+/-1.72 years) suffering from hypothalamic stress-related amenorrhea with normal body weight and 8 age-matched healthy controls in the follicular phase of the menstrual cycle. METHODS: We measured basal serum levels of FSH, LH, and estradiol and evaluated ACTH, allopregnanolone and cortisol responses to CRH test in both HA patients and healthy women. RESULTS: Serum basal levels of FSH, LH, and estradiol as well as basal levels of allopregnanolone were significantly lower in HA patients than in controls (P<0.001) while basal ACTH and cortisol levels were significantly higher in amenorrheic patients with respect to controls (P<0.001). The response (area under the curve) of ACTH, allopregnanolone and cortisol to CRH was significantly lower in amenorrheic women compared with controls (P<0.001, P<0.05, P<0.05 respectively). CONCLUSIONS: In conclusion, women with HA, despite the high ACTH and cortisol levels and, therefore, hypothalamus-pituitary-adrenal axis hyperactivity, are characterized by low allopregnanolone basal levels, deriving from an impairment of both adrenal and ovarian synthesis. The blunted ACTH, allopregnanolone and cortisol responses to CRH indicate that, in hypothalamic amenorrhea, there is a reduced sensitivity and expression of CRH receptor. These results open new perspectives on the role of neurosteroids in the pathogenesis of hypothalamic amenorrhea.
Induction of cellular immunity in a parathyroid carcinoma treated with tumor lysate-pulsed dendritic cells
Authors: Schott M , Feldkamp J , Schattenberg D , Krueger T , Dotzenrath C , Seissler J , Scherbaum WA
Published: January 2005

BACKGROUND: Cytotoxic T-lymphocyte-mediated tumor immunity against major histocompatibility antigen class II-negative tumors requires help from CD4(+) T-cells. The major antigen presenting cells for CD4(+) cell activation are dendritic cells. Studies in mice and humans have demonstrated the potent capacity of these cells to induce specific antitumor immunity. OBJECTIVE: To control the growth of a metastasized parathyroid carcinoma, by immunizing a patient with tumor lysate and parathyroid hormone-pulsed dendritic cells. DESIGN AND METHODS: Mature dendritic cells were generated from peripheral blood monocytes in the presence of granulocyte/macrophage colony-stimulating factor, interleukin-4 and tumor necrosis factor alpha. Antigen-loaded dendritic cells were delivered by subcutaneous and intralymphatical injections. After five cycles, we added keyhole limpet hemocyanin (KLH) as a CD4(+) helper antigen. RESULTS: After 10 vaccinations, a specific cellular immune response to tumor lysate was observed. In vitro T-cell proliferation assays revealed a dose-dependent stimulation index of 1.8-5.7 compared with 0.9-1.1 before vaccination. In vivo immune response was demonstrated by positive delayed-type hypersensitivity toward tumor lysate. Intradermal injection of tumor lysate resulted in an erythema and induration, suggesting the efficient generation of tumor lysate-specific memory T-cells. CONCLUSIONS: These data indicate that dendritic cell vaccination can induce in vitro and in vivo responses in a highly malignant endocrine carcinoma. Regardless of the clinical outcome of our patient, this approach might be generally applicable to other advanced, radio- and chemotherapy-resistant endocrine malignancies, such as adrenal carcinomas and metastasized medullary and anaplastic thyroid carcinomas.
Growth hormone isoforms in newborns and postpartum women
Authors: Boguszewski CL , Boguszewski MC , de Zegher F , Carlsson B , Carlsson LM
Published: January 2005

The neonatal and postpartum periods are characterized by alterations in pituitary GH secretion. We have investigated the proportion of circulating non-22kDa GH isoforms in newborns, in women within the early postpartum phase (just after the disappearance of placental GH from the maternal circulation) and in women during late postpartum (during the somatotroph recovery phase). We studied 10 newborns (7 males; 3 females; median postnatal age, 45h), who had been admitted because of polycythaemia, 10 women in the early postpartum phase (median, 48h after delivery; range, 42-54h), 18 women in the late postpartum phase (median, 10 weeks after delivery; range, 3-25 weeks) and 9 healthy non-pregnant women. The proportion of non-22kDa GH isoforms was determined by the 22kDa GH exclusion assay, which is based on immunomagnetic extraction of 22kDa GH from serum, and quantitation of non-22kDa GH isoforms using a polyclonal GH assay. In newborns, non-22kDa GH isoforms were measured in two arterial blood samples obtained with a 5-6h interval. In the other groups, serum samples were obtained 40min after an i.v. bolus administration of the GH secretagogue, GH releasing peptide-1 (GHRP-1).In newborns, the median proportion of non-22kDa GH isoforms was 10% (range, 7. 2-19.4%) and the values were similar in samples collected at different times. In early postpartum women, total GH levels after GHRP-1 were lower and the proportion of non-22kDa GH isoforms was higher compared with the values in non-pregnant and late-postpartum women. In late postpartum, there was a partial recovery of GH response to GHRP-1, as shown by an increment in total GH levels, which was associated with a decrease in the fraction of non-22kDa GH isoforms. In conclusion, we found that (i) the proportion of non-22kDa GH isoforms in the newborn is comparable to that in the adult (non-pregnant women), (ii) in early postpartum, the non-22kDa fraction is high within the small pool of readily releasable GH, (iii) in late postpartum, recovery of pituitary GH responsiveness is associated with a relative decrease in the release of non-22kDa GH isoforms.
Longitudinal changes of circadian leptin, insulin and cortisol plasma levels and their correlation during refeeding in patients with anorexia nervosa
Authors: Herpertz S , Albers N , Wagner R , Pelz B , Kopp W , Mann K , Blum WF , Senf W , Hebebrand J
Published: January 2005

OBJECTIVE: To study the longitudinal changes in plasma levels of leptin, insulin and cortisol during the transition from the state of starvation to the state of refeeding focussing on diurnal secretion characteristics and their temporal relationships. DESIGN: Leptin, insulin and cortisol were measured every 2h for 24h during acute starvation (T1). Sampling was repeated after reaching half the target-body mass index (BMI) (T2) and again at target-BMI (17. 5kg/m(2); T3). The temporal relationships between the diurnal secretion patterns were assessed by cross-correlation analysis. RESULTS: Although BMIs at T1 were uniformly low, leptin levels varied widely within a range clearly below normal levels (0.03-1. 7microg/l). With increasing body fat during the course of refeeding, mean leptin levels increased from 0.64microg/l (range: 0.27-1. 73microg/l) (T1) to 1.61microg/l (range: 0.36-4.2microg/l) (T2) and to 3.67microg/l (range: 0.7-9.8microg/l) (T3). Circadian leptin secretion patterns showed maximal values uniformly around 0200h and minimal values around 0800h at all stages of the study. At all three weight levels, plasma leptin levels were highest between midnight and the early morning hours and lowest around the late morning hours. Refeeding neither profoundly changed secretion patterns of leptin nor did it change the positive, time-delayed relationship between leptin and insulin with increments in insulin secretion preceding those of leptin by 6h. A temporal relationship between leptin and cortisol could not be demonstrated in the state of semistarvation but emerged after a substantial weight gain; at that time, leptin increases preceded cortisol increases by 8h. CONCLUSIONS: Absolute leptin, insulin and cortisol levels are profoundly changed during starvation in anorectic patients, while refeeding, paralleled by a BMI gain, reverses these changes. During refeeding the relationship between leptin and cortisol changed profoundly, showing no significant correlation in the state of starvation, whereas at T3 after refeeding a strong inverse relationship could be observed. Leptin and insulin did not correlate significantly at any of the three stages studied.
Melatonin secretion from organ-cultured pineal glands of rats: modulation by gonadectomy and gonadotropin-releasing hormone agonist administration
Authors: Ishizuka B , Fusama S , Hirai K , Hosaka T , Hamada N , Amemiya A , Itoh MT
Published: January 2005

The objective of the study was to evaluate the effect of pretreatments such as gonadectomy in male and female rats, and gonadotropin-releasing hormone agonist (GnRHa) administration in female rats, on levels of secretion of melatonin, using an organ culture of pineal glands. Gonadectomy 2 weeks before the animal was killed increased the amount of melatonin secreted into the medium by the pineal glands of female rats but not of male rats. The increase in in vitro melatonin secretion after ovariectomy in female rats was prevented by estrogen replacement. Ovariectomy 3 and 4 weeks before death also significantly increased the amount of melatonin secretion. Administration of GnRHa 2 weeks before decapitation significantly decreased serum estradiol concentrations and significantly increased melatonin secretion by the pineal glands of female rat. GnRHa administration 3 or 4 weeks before decapitation also significantly decreased serum estradiol concentrations, but did not increase pineal secretion of melatonin. The results indicate that ovariectomy increases melatonin secretion from organ-cultured pineal glands and that this increase is suppressed by estrogen in adult female rats. In contrast, orchiectomy in male rats does not influence in vitro secretion of melatonin. These results suggest that the GnRH-gonadotropin system may participate in the regulation of pineal melatonin secretion in adult female rats.
Immediate changes in biochemical markers of bone turnover and circulating interleukin-6 after parathyroidectomy for primary hyperparathyroidism
Authors: Guo CY , Holland PA , Jackson BF , Hannon RA , Rogers A , Harrison BJ , Eastell R
Published: January 2005

OBJECTIVE: The time course of the immediate change in bone turnover after parathyroidectomy (PTX) for primary hyperparathyroidism (PHPT) is not clear. It is uncertain whether circulating interleukin-6 (IL-6) plays a role in mediating the acute withdrawal of the effects of parathyroid hormone (PTH) on bone turnover after PTX. The aims of this study were to determine the time course of immediate changes in biochemical markers of bone turnover after PTX and whether circulating IL-6 is involved in the immediate changes of bone turnover after PTX. DESIGN AND METHODS: IL-6 and bone turnover markers were measured in eight women (aged 55+/-11 years, mean+/-s.d. ) with PHTP at baseline and at 1-2h, and 1, 2, 5, 7 and 12 days after PTX. We compared the results with those from eight individually matched women (healthy controls) and five subjects undergoing major surgery (surgical controls). RESULTS: At baseline, serum levels of IL-6 and bone turnover markers were higher in PHPT than those in healthy controls (P<0.05). Serum levels of procollagen propeptides increased by 22 and 27% at days 2 and 5, respectively, compared with baseline (P<0.05). Serum tartrate-resistant acid phosphatase decreased by 2 days after PTX, and urinary collagen crosslinks decreased significantly by 21-41% within 24h (P<0.05). Serum IL-6 levels increased immediately in both PHPT and surgical controls at postoperative follow-up (repeated measures ANOVA). CONCLUSIONS: (1) PTX decreases bone resorption immediately and (2) circulating IL-6 is not involved in the changes in bone turnover immediately after PTX.
Secretion of inhibin B by human prepubertal testicular cells in culture
Authors: Berensztein E , Saraco N , Belgorosky A , Rivarola MA
Published: January 2005

OBJECTIVE: Inhibin B is a secretory product of Sertoli cells of the human testis. It has been reported that serum levels of inhibin B in infant boys, peaking at 3 months of age, exceed levels in adult men. The aim of this study was to evaluate inhibin B secretion in primary prepubertal mixed testicular cell cultures, prepared from testes collected at necropsy. DESIGN AND METHODS: Cell cultures were divided into three age groups on the basis of differences in testicular histology: group 1 (n = 7), 1- to 10-day-old newborns, group 2 (n = 7), 1- to 9-month-old infants, and group 3 (n = 8), 12- to 84-month-old children. Cells were maintained in culture for 6 days, harvested and counted. In some samples, during the last 4 days, cells were stimulated with 10ng/ml highly purified human (h) LH (n = 9), 2 ng/ml recombinant human (rh) FSH (n = 9) or 50 ng/ml rhGH (n = 4). On day 6, the secretion of inhibin B and testosterone into the medium was estimated in triplicate. Inhibin B was determined by ELISA and testosterone by RIA. RESULTS: Median (range) inhibin B secretion was 465 (225-1007), 275 (107-298), and 58 (15-184) pg/million cells.24h in groups 1, 2 and 3 respectively. A logarithmic transformation of these values was performed to normalize data. Mean+/-s.d. of transformed inhibin B secretion in group 1 was significantly higher than in group 2 or 3 (P<0.005) and the values for groups 1 and 2 were significantly higher than that for group 3 (P< 0.005). No significant correlation between testosterone and inhibin B secretion into the medium was found when the 22 culture samples were analyzed as a whole. Inhibin B secretion was significantly increased after stimulation with highly purified hLH, rhFSH and rhGH (P < 0.05) and a significant positive correlation between inhibin B and testosterone was found under both hLH and rhFSH stimulation. CONCLUSIONS: It is concluded that cells collected from newborns have the highest capacity to secrete inhibin B in vitro, and that this capacity decreases with age during the first years of life. Since no data are available on serum inhibin levels in newborns, it is possible that concentrations at 3 months of age do not represent a post-natal peak but a declining level of high newborn values. As expected, FSH stimulated inhibin B secretion in culture. LH stimulation was probably mediated by paracrine factors secreted by interstitial cells. Finally, our results add new evidence of the involvement of GH in testicular maturation.
Resting metabolic rate, body composition, and serum leptin concentrations in a free-living elderly population
Authors: Neuhauser-Berthold M , Herbert BM , Luhrmann PM , Sultemeier AA , Blum WF , Frey J , Hebebrand J
Published: January 2005

OBJECTIVE: The present study investigated the relationship between serum leptin concentrations and resting metabolic rate (RMR) in a large study group of elderly individuals with special consideration of body composition and body fat distribution as possible confounders. DESIGN AND METHODS: The subjects were 122 women (age: 69+/-6 years, body mass index (BMI): 26.3+/-3.6 kg/m(2)) and 82 men (age: 69+/-5 years, BMI: 26.0+/-2.6 kg/m(2)). RMR was measured by indirect calorimetry and body composition by the bioelectrical impedance method. Serum leptin levels were determined by radioimmunoassay. RESULTS: There was a strong correlation between fat mass (FM) and serum leptin levels in both sexes. An age-related decline in leptin levels adjusted for FM was observed only in the women. After adjustment of RMR for both fat-free mass (FFM) and FM, leptin levels were not associated with RMR. In stepwise multiple regression analysis, FFM was the main predictor of RMR, explaining 35.8% and 47.6% of the variance of RMR in men and women respectively. FM did not explain variance in RMR in men, but accounted for 2.6% of the variance in RMR in women. Waist-hip-ratio and age influenced RMR only in males, explaining 5.7% and 4.0% of the variance in RMR respectively. CONCLUSION: Leptin is not a significant predictor of RMR in the elderly, but body composition and distribution of body fat are significantly associated with RMR.
Effect of activin on production and secretion of prolactin and growth hormone in cultured rat GH3 cells
Authors: Tamura N , Irahara M , Kuwahara A , Ushigoe K , Sugino H , Aono T
Published: January 2005

OBJECTIVE: To evaluate the effect of the growth factor activin A on the secretion of prolactin (PRL) and GH in cultured GH3 cells. METHODS: The concentrations of PRL and GH secreted from GH3 cells cultured in media with and without activin A were measured by RIA, and the expression of PRL mRNA and GH mRNA were analyzed using the Northern blot method. RESULTS: Activin A significantly inhibited PRL release from GH3 cells cultured for 48h in a dose-dependent manner (activin: 0.3-3nM). The inhibitory effects of 3nM activin A were observed in the culture from 12h to 48h (53.2% of control). Activin A (3nM) also significantly inhibited the expression of PRL mRNA at 24h (33.8% of control). In contrast, activin A significantly stimulated GH release from GH3 cells cultured for 48h in a dose-dependent manner (activin: 0.3-3nM). The stimulatory effect of 3nM activin A was observed in the culture for 48h (157.6% of control). Activin A (3nM) also significantly stimulated the expression of GH mRNA at 24h (183.6% of control). In spite of these significant changes in PRL and GH secretion, pit-1 mRNA levels were not significantly changed by activin A. CONCLUSIONS: These findings indicated that activin A modulates PRL and GH secretion through the regulation of PRL and GH gene transcription in GH3 cells, but that these effects are unrelated to pit-1 gene expression.
Recombinant human growth hormone enhances tibial growth in peripubertal female rats but not in males
Authors: Rol De Lama MA , Perez-Romero A , Tresguerres JA , Hermanussen M , Ariznavarreta C
Published: January 2005

OBJECTIVE: A novel non-invasive technique termed microknemometry, which allows daily leg length measurement, was used to investigate the growth promoting effect of growth hormone (GH) on peripubertal rats. We compared the effect of different patterns of recombinant human (rh) GH administration to peripubertal male rats with the effect produced by two daily administrations of the same amount of rhGH to peripubertal female rats or adult male rats. Another group of peripubertal male rats was also submitted to a 3-day period of starvation, in order to study catch-up growth during refeeding and to determine whether this process could be stimulated by exogenous GH administration. RESULTS: GH treatment was unable to stimulate tibial growth or weight gain in peripubertal males, whereas a clear growth promoting effect was observed in female rats and also in adult male rats. Starvation caused a dramatic body weight loss, and a reduction in tibial growth rate. Peripubertal male rats gained body weight faster than unstarved animals during refeeding, although recovery was not complete after nine days. Tibial growth, however, was resumed at the same speed as in normally fed males. This means that no catch-up effect was observed after refeeding in animals either with or without GH treatment. CONCLUSIONS: During peripuberty, normal male rats grow at a maximal speed that cannot be further increased by exogenous GH treatment, whereas age-matched female rats or older males grow at a slower rate than peripubertal males. Thus, exogenous rhGH administration is capable of enhancing growth velocity.
Fetal leptin and insulin levels only correlate inlarge-for-gestational age infants
Authors: Wolf HJ , Ebenbichler CF , Huter O , Bodner J , Lechleitner M , Foger B ,   Patsch, Desoye G
Published: January 2005

OBJECTIVE: To determine whether fetal leptin levels correlate with fetal weight and whether such correlation is direct or indirect via insulin or human placental lactogen (hPL), respectively. DESIGN: Cross-sectional study of offspring at term (n=175) with over-representation of large-for-gestational age (LGA; n=70) and small-for-gestational age (SGA; n=23) cases in a population of Caucasian women with no pregnancy pathology. METHODS: Fetal cord blood was collected after delivery. In several cases (n=62) paired mother-fetus blood samples were obtained. Leptin, insulin and hPL levels were measured by RIA. Anthropometric data (birth weight, body mass index, placental weight) were recorded. RESULTS AND CONCLUSIONS: Maternal insulin, hPL and leptin levels were higher than fetal concentrations. Cord blood leptin levels positively correlated with the anthropometric data with stronger correlations in female (0.54<r<0.66) than in male (0.32<r<0.39) neonates. Cord blood leptin levels did not differ between appropriate-for-gestational age (AGA; n=82) and SGA (n=23) neonates, but were higher (P<0.001) by 83% in LGA (n=70) than in AGA neonates. Among the different weight classes the correlations between fetal leptin and anthropometric data were only observed in LGAs, but not in AGAs or SGAs. Fetal, but not maternal, leptin levels strongly correlated with fetal insulin (r=0.56; P<0.001). After accounting for this close relationship insulin could no longer be used to predict birth weight (r=0.15, P=0.051). We suggest that the correlation of cord blood insulin with neonatal weight in LGAs is, in addition to insulin's direct anabolic action, indirectly mediated via leptin. It is hypothesized that fetal insulin stimulates fetal adipocyte leptin production.
Expression of RET and its ligand complexes, GDNF/GFRalpha-1 and NTN/GFRalpha-2, in medullary thyroid carcinomas
Authors: Frisk T , Farnebo F , Zedenius J , Grimelius L , Hoog A , Wallin G , Larsson C
Published: January 2005

OBJECTIVE: Mutations in the RET proto-oncogene are found in about one third of sporadic medullary thyroid carcinomas (MTCs), mostly affecting codon 918. Glial cell line derived neurotropic factor (GDNF) and its membrane-bound GDNF family receptor alpha (GFRalpha-1), as well as neurturin (NTN) and its membrane-bound receptor GFRalpha-2 form a complex with the RET product, a receptor tyrosine kinase, resulting in downstream signaling to the nucleus. DESIGN: To elucidate the role of these RET ligands in MTC tumorigenesis, their expression was determined in 15 MTC samples, one papillary thyroid carcinoma (PTC) and three normal thyroid tissue specimens. METHODS: The mRNA expression of RET, GDNF, GFRalpha-1, NTN and GFRalpha-2 was investigated by mRNA in situ hybridization, and confirmed by reverse transcription-PCR analysis. RESULTS: None of the five genes was expressed in the normal thyroids or in the PTC. All MTCs showed expression of RET, 13 expressed GDNF, 12 expressed GFRalpha-1 and 9 expressed NTN and GFRalpha-2. In 7 of the tumors RET, GDNF and GFRalpha-1 were expressed at high levels, and in five of these seven tumors NTN and GFRalpha-2 genes were also expressed at high levels. The high level of expression was preferentially seen in tumor cells adjacent to stroma and connective tissue. All MTCs without expression of the RET ligands harbored the RET codon 918 mutation. CONCLUSIONS: The results suggest that this signaling pathway is important for MTC development, and that it may be activated by expression of the RET ligand complexes by the tumor cells themselves.
Evidence for co-ordinated changes between vascular endothelial growth factor and nitric oxide synthase III immunoreactivity, the functional status of the thyroid follicles, and the microvascular bed during chronic stimulation by low iodine and propylthiouracyl in old mice
Authors: Gerard AC , Xhenseval V , Colin IM , Many MC , Denef JF
Published: January 2005

Vasoactive and angiogenic factors are involved in the autocrine/paracrine thyroid regulation of microvascular bed during goiter development. In the thyroid of old mice, the presence of slowly functioning ('cold') follicles allowed us to study the microvascular regulation of each follicle in correlation with the immunohistochemical expression of vascular endothelial growth factor (VEGF) and nitric oxide synthase III (NOSIII). Mice aged 20 months did or did not receive a goitrogenic treatment (low iodine diet and propylthiouracyl), and their thyroids were processed for light and electron microscopy, and for autoradiography. The relative volumes (Vv) of the capillaries, the number of vessels per follicular area, the mean capillary area and the number of [(3)H]thymidine labeled nuclei were measured separately for 'hot' and 'cold' follicles. Already in control mice, the capillary bed surrounding 'hot' follicles was significantly larger than that seen around 'cold' follicles, because of larger diameters and twice the number of capillaries. This difference persisted whatever the length of the stimulatory treatment. During this treatment, the Vv of the capillaries increased to a larger extent around 'hot' follicles than around 'cold' ones. All vascular changes around 'cold' follicles were less extended and the increase in the capillary diameter was delayed. In control mice, the 'cold' follicles were negative for NOSIII and positive for VEGF while 'hot' follicles were positive for both. During stimulation, all follicles became progressively NOSIII positive. These data support the concept of 'angio-follicular units' in the thyroid and demonstrate their differential regulation in chronic stimulation during which local secretion of VEGF and NO is clearly involved.
Involvement of osteoprotegerin/osteoclastogenesis inhibitory factor in the stimulation of osteoclast formation by parathyroid hormone in mouse bone cells
Authors: Kanzawa M , Sugimoto T , Kanatani M , Chihara K
Published: January 2005

OBJECTIVE: Recently, osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) has been shown to inhibit osteoclast differentiation. On the other hand, we have reported that parathyroid hormone (PTH) stimulated osteoclast formation, presumably through a PTH-responsive cAMP-dependent protein kinase (PKA) pathway, in mouse bone cells. DESIGN AND METHODS: The present study was performed to examine how OPG/OCIF expression is regulated by PTH and to further investigate the possible involvement of OPG/OCIF in the stimulation of osteoclast formation by PTH in mouse bone cells. OPG/OCIF mRNA expression was analyzed by Northern hybridization after 24h treatments of mouse whole bone cells and mouse stromal cell line, ST2 cells with PTH or various second messenger analogs. RESULTS: Human (h) PTH(1-34) (10(-10) and 10(-8)mol/l) but not 10(-8)mol/l hPTH(3-34) down-regulated OPG/OCIF mRNA expression in mouse bone cells. Dibutyryl cAMP, but not phorbol ester, an activator of protein kinase C, or A23187, a calcium ionophore, down-regulated it. The same was also observed in ST2 cells, suggesting that stromal cells are responsible for the inhibitory effect of PTH and cAMP analogs on OPG/OCIF mRNA expression in mouse bone cells. CONCLUSIONS: The present study indicates that PTH down-regulates OPG/OCIF mRNA expression through the PKA pathway in stromal cells, which would result in the stimulation of osteoclast formation.
LHRH might act as a negative autocrine regulator of proliferation of human ovarian cancer
Authors: Emons G , Weiss S , Ortmann O , Grundker C , Schulz KD
Published: January 2005

OBJECTIVE: More than 80% of human ovarian cancers express LHRH and its receptor. The proliferation of human ovarian cancer cell lines is reduced by both LHRH agonists and antagonists. This study was designed to further clarify the possible biological function of this LHRH system. DESIGN: As LHRH agonists and antagonists uniformly reduce proliferation of human ovarian cancer in a dose-dependent way, the effect of low concentrations of authentic LHRH was studied. In addition, longer periods of treatment (up to 9 days) were analyzed. To assess the physiological role of LHRH produced by ovarian cancer cells it was neutralized by adequate concentrations of a specific LHRH antiserum. METHODS: Human ovarian cancer cells EFO-21 and EFO-27, which express LHRH and its receptor, were incubated for 1-9 days with increasing concentrations (1pmol/l to 10 micromol/l) of authentic LHRH or with concentrations of LHRH antiserum capable of neutralizing at least 1nmol/l LHRH. Proliferation was assessed by counting cells. RESULTS AND CONCLUSIONS: Authentic LHRH reduced time- and dose-dependently proliferation (by maximally mean+/-s.e.m. 32.7 +/- 4.4%, Newman-Keuls, P < 0.001) of both ovarian cancer cell lines. At very low concentrations (1pmol/l) a marginal reduction of proliferation or no effect was observed. A mitogenic effect of authentic LHRH was never detected. Treatment of ovarian cancer cell cultures with antiserum to LHRH significantly increased (up to mean+/-s.e.m. 121.0 +/- 2.8% of controls, Newman-Keuls P <0.001) proliferation of EFO-21 and EFO-27 cells. These findings suggest that LHRH produced by human ovarian cancer cells might act as a negative autocrine regulator of proliferation.
Expression of adrenomedullin by human granulosa lutein cells and its effect on progesterone production
Authors: Moriyama T , Otani T , Maruo T
Published: January 2005

OBJECTIVE: Adrenomedullin (AM) has diverse functions and is expressed in a variety of tissues. This study was conducted to investigate the expression of AM in the human ovary and its effect on progesterone production by human granulosa lutein cells. DESIGN AND METHODS: Follicular fluid and blood samples were obtained at the time of oocyte retrieval from patients undergoing in vitro-fertilization cycles. Concentrations of AM in follicular fluid and plasma were measured by RIA. Granulosa cells were isolated from follicular fluid and expression of AM mRNA was examined by RT-PCR. Granulosa lutein cells were cultured in vitro and secretion of AM by those cells was determined by immunoprecipitation followed by PAGE. Immunohistochemical staining with human ovaries was carried out, using a specific antibody to AM. Furthermore, the effect of AM on progesterone production by cultured granulosa lutein cells was studied. RESULTS: Concentrations of AM in follicular fluid collected just before ovulation were significantly higher than those in the plasma (P<0.01). AM mRNA was expressed in granulosa cells at the preovulatory stage. Cultured granulosa lutein cells secreted immunoreactive AM. With immunohistochemical staining, it was revealed that AM was most abundantly expressed in granulosa lutein cells at the midluteal phase. No appreciable staining for AM was observed in granulosa cells in primordial and preantral follicles, whereas immunolocalization of AM was noted in granulosa cells of dominant follicles although it was not as prominent as in granulosa lutein cells at the midluteal phase. Furthermore, addition of AM to cultured granulosa lutein cells augmented progesterone secretion in a dose-dependent manner. CONCLUSIONS: These results suggest that AM is transcribed and secreted in human granulosa lutein cells as a local factor to enhance progesterone production by those cells.
Adrenocortical function in patients with macrometastases of the adrenal gland
Authors: Lutz A , Stojkovic M , Schmidt M , Arlt W , Allolio B , Reincke M
Published: January 2005

OBJECTIVE: Metastases of the adrenal gland are a frequent finding in patients with malignant tumors like bronchogenic carcinoma or breast cancer. Only limited and conflicting data on adrenocortical function in these patients are available. DESIGN: Cross-sectional study. METHODS: We investigated the impact of adrenal macrometastases on adrenocortical function in a series of 28 tumor patients using the ACTH(1-24) stimulation test and dexamethasone suppression test. Seven normal controls (Con), eleven patients without adrenal metastases (No Met), eight patients with unilateral (Uni Met) and nine patients with bilateral adrenal metastases (Bil Met) were investigated. RESULTS: The prevalence of adrenal insufficiency was low in our study population, with only two of nine patients with bilateral metastases having subclinical adrenocortical insufficiency. In the remaining patients with uni- or bilateral metastases, baseline and stimulated cortisol concentrations were higher than in controls and cancer patients without metastases (baseline cortisol (in nmol/l): Con: 307+/-33.2 vs Uni Met: 440+/-53.5, and Bil Met: 637.6+/-92.1, P=0.04 by ANOVA; cortisol 60 min after ACTH(1-24): Con: 794.6+/-41.2 vs Uni Met: 990.8+/-92.9, and Bil Met: 1151.4+/-155.5, P=0.03 by ANOVA). Simultaneously, baseline and stimulated serum aldosterone concentrations were significantly blunted in the tumor groups. CONCLUSIONS: Adrenal insufficiency is infrequent and develops only in patients with bilateral metastases. However, the majority of patients have activation of the hypothalamic-pituitary-adrenal axis despite adrenal metastases with strongly elevated cortisol concentrations.
Functional characteristics of insulin receptors with a Thr-->Ser1200 mutation overexpressed in Chinese hamster ovary cells
Authors: Schutt M , Benecke H , Drenckhan M , Klein HH
Published: January 2005

OBJECTIVE: To investigate the functional properties of insulin receptors with a Thr-->Ser(1200)-mutation that is associated with severe insulin resistance in humans. DESIGN AND METHODS: The effect of in situ insulin-stimulation on insulin receptor kinase activity was studied in Chinese hamster ovary cells with overexpressed human Ser(1200)-mutated, non-mutated, and ATP-binding site-mutated (Lys-->Arg(1030)) receptors using a microwell-based assay that only detects human (and not hamster) insulin receptors. Moreover, the fraction of anti-phosphotyrosine antibody-binding receptors following in situ stimulation was separated, and autophosphorylation and kinase activity resulting from in situ and/or in vitro activation evaluated in this fraction. RESULTS: Although insulin-stimulated kinase activity of human-specific anti-insulin receptor antibody-binding receptors in cells with Ser(1200)-mutated insulin receptors represented only 3.3% of that reached in cells with non-mutated receptors, a clear insulin-induced increase in kinase activity was observed (3.4-fold; P<0.05). This increase was associated with a 2.3+/-0.6% (P<0.05) increase in anti-phosphotyrosine-binding receptors with a kinase activity representing 43+/-8% of that found in activated non-mutated receptors. In vitro autophosphorylation and kinase activation proceeded much more slowly in Ser(1200)-mutated receptors (t(1/2)): 100 min) compared with non-mutated receptors (t(1/2)): 1 min) and were inhibitable by lower alkaline phosphatase concentrations (EC(50): 3 U/ml and 70 U/ml respectively). No activation of insulin receptor kinase was observed with Arg(1030)-mutated receptors. CONCLUSIONS: Overexpressed Ser(1200)-mutated human insulin receptors possess insulin-stimulated kinase activity and can be activated in situ and in vitro. They are characterized by a markedly slower autophosphorylation reaction, which, in a phosphatase-containing environment, results in a small fraction of phosphorylated and activated receptors.