bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum leptin in short children born small for gestational age: relationship with the growth response to growth hormone treatment. The Swedish Study Group for Growth Hormone Treatment
Authors: Boguszewski M , Dahlgren J , Bjarnason R , Rosberg S , Carlsson LM , Carlsson B , Albertsson-Wikland K
Published: January 2005

The product of the obese (ob) gene, leptin, is an adipocyte-derived hormone that is involved in the regulation of appetite and body weight. This study was undertaken in order to describe the basal serum levels of leptin in prepubertal short children born small for gestational age (SGA) and their relationship with growth parameters, before and during growth hormone (GH) treatment. Eighty-nine prepubertal short children (66 boys, 23 girls; height standard deviation score (SDS), -5.4 to -2.0; age, 2.0 to 12.8 years) born SGA, 12 of whom (9 boys, 3 girls) had signs of Silver-Russell syndrome, were included in the study. Serum leptin concentrations were measured by radioimmunoassay. Leptin levels in the children born SGA were compared with those in a reference group of 109 prepubertal healthy children born at an appropriate size for gestational age (AGA). The mean (S.D.) change in height SDS was 0.11 (0.22) during the year before the start of GH therapy (0.1 IU/kg/day) and increased to 0.82 (0.44) during the first year (P < 0.001) and to 1.28 (0.59) during the 2-year period of GH therapy (P < 0.001). The children born SGA were significantly leaner than the reference group. An inverse correlation was found between leptin and chronological age in the SGA group (r = -0.31, P < 0.01). The mean serum level of leptin in the children born SGA who were older than 5.5 years of age was 2.8 micrograms/l which was significantly lower than the mean value of 3.7 micrograms/l found in the children born AGA of the same age range. The difference remained after adjustment of leptin levels for sex, age, body mass index (BMI) and weight-for-height SDS (WHSDSSDS). Leptin correlated with WHSDSSDS (r = 0.32, P < 0.001) and BMI (r = 0.36, P < 0.01) in the reference population, but not in the SGA group. No correlation was found between leptin and spontaneous 24-h GH secretion, insulin-like growth factor (IGF)-I or IGF-binding protein-3 levels, or with fasting insulin or cortisol levels. Leptin levels at the start of GH treatment were correlated with the growth response over both 1 year (r = 0.46, P < 0.001) and 2 years (r = 0.51, P < 0.001) of GH therapy. Using multiple regression analysis, models including leptin levels at the start of GH therapy could explain 51% of the variance in the growth response after 1 year and 44% after 2 years of GH treatment. In conclusion, serum leptin levels are reduced in short children born SGA and are inversely correlated with chronological age. Leptin concentrations correlate with the growth response to GH treatment and might be used as a marker for predicting the growth response to GH treatment.
High molecular weight forms of IGF-II ('big-IGF-II') released by Wilms' tumor cells
Authors: Schmitt S , Ren-Qiu Q , Torresani T , Doebeli M , Zapf J , Schoenle EJ
Published: January 2005

Insulin-like growth factor-II (IGF-II) is thought to play a critical role in the development of embryonic tumors such as Wilms' tumor. However, despite highly elevated IGF-II mRNA levels in tumors, IGF-II is not elevated in the serum of patients with Wilms' tumors. Recently high molecular weight forms of IGF-II ('big'- or pro-IGF-II) have been found to be produced by some tumors. In order to prove whether or not high molecular weight forms of IGF-II are produced by Wilms' tumor cells and secreted into the culture medium, we established Wilms' tumor cell lines. After column chromatography of the culture medium, IGF-II and pro-IGF-II concentrations were measured. For pro-IGF-II measurement we established a pro-IGF-II RIA using a rabbit polyclonal antiserum directed against amino acids 7-21 (E7-21) of the E-domain of pro-IGF-II. Gel electrophoresis and Western blotting with anti-IGF-II antibodies revealed a band at 7.5 kDa corresponding to fully processed IGF-II and bands between 10 and 20 kDa. Using pro-IGF-II antiserum, bands between 10 and 25 kDa were detected. We conclude that in vitro cultured Wilms' tumor cells produce and release various forms of 'big IGF-II' with molecular masses between 10 and 25 kDa. It remains uncertain whether these high molecular weight forms of IGF-II represent normal precursors of IGF-II or incorrectly processed IGF-II.
Retinoic acid receptors alpha, beta and gamma, and cellular retinol binding protein-I expression in breast fibrocystic disease and cancer
Authors: Pasquali D , Bellastella A , Valente A , Botti G , Capasso I , del Vecchio S , Salvatore M , Colantuoni V , Sinisi AA
Published: January 2005

Retinoids seem to act as agents of chemoprevention and differentiation in breast diseases. Their action is mediated by nuclear receptors, retinoic acid receptors (RAR alpha, RAR beta, RAR gamma) and retinoid X receptors (RXR alpha, RXR beta, RXR gamma) and modulated by cellular retinol binding proteins (CRBP). There are few published data on CRBP expression. In this study, we evaluated the expression of RAR alpha, beta and gamma and CRBP type I (CRBP-I) gene expression in fibrocystic disease (FD) and in breast cancer (BC), studying 14 FD and 20 BC surgical samples by reverse transcription (RT)-PCR. We also evaluated mRNA concentrations in cancer samples by a semiquantitative PCR method, co-amplifying RAR alpha, RAR beta and CRBP-I genes with an unrelated gene, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), as internal control. All benign and malignant breat tissues expressed RAR alpha, beta and gamma, and CRBP-I mRNAs. A greater concentration of RAR beta mRNA was detected in cancer tissues with lower oestrogen and progesterone receptor concentrations, whereas RAR alpha was detected in variable concentrations that were not related to those of steroid receptors. The CRBP-I concentration was similar in all samples studied. We demonstrated that all three RARs and CRBP-I transcripts are expressed in FD, and that RAR beta, RAR gamma and CRBP-I mRNAs also are present in BC tissues. This indicates that both malignant and benign breast tissues may be target for retinoids, justifying the use of natural and synthetic vitamin A derivatives in the chemoprevention of breast disease.
Modulation of T3-induced sex hormone-binding globulin secretion by human hepatoblastoma cells
Authors: Payne KL , Loidl NM , Lim CF , Topliss DJ ,   Stockigt, Barlow JW
Published: January 2005

We have shown previously that tri-iodothyronine (T3)-induced sex hormone-binding globulin (SHBG) secretion by the human hepatoblastoma cell line, HepG2, can be modulated by retinoids. We have now used this model to study a range of other compounds that are known to influence T3 responsiveness in various cell systems. HepG2 cells were incubated for 4 days in serum-free medium containing T3, together with insulin, dexamethasone, phorbol myristate (PMA), sodium butyrate or estradiol. T3 (10 nmol/l) alone induced a concentration of SHBG secreted by HepG2 cells that was 187 +/- 20% (mean +/- S.D., n = 9) of control. Insulin (100 nmol/l) reduced basal SHBG secretion from 24.7 +/- 5.2 nmol/l to 16.1 +/- 1.7 nmol/l (P < 0.01). This effect was dose responsive, half-maximal at 3.4 +/- 3.0 nmol/l (approximately 600 mU/l) and maximal with 100 nmol/l insulin. Co-incubating 0-10 nmol/l T3 with 100 nmol/l insulin resulted in a downward shift in the dose-response curve without a change in the half-maximal response to T3. Conversely, 0-100 nmol/l insulin reduced SHBG production induced by 10 nmol/l T3. In contrast; while dexamethasone alone was without effect on SHBG secretion, 100 nmol/l dexamethasone induced a shift to the left in half-maximal T3 stimulation from 0.37 nmol/l to 0.10 nmol/l. The effect of PMA on SHBG secretion was reminiscent of the previously observed retinoid effect. PMA 100 nmol/l abolished maximal T3 stimulation. This effect was dose responsive, with a threshold at 1 nmol/l PMA. Sodium butyrate, up to 1 mmol/l was without effect; with greater concentrations, SHBG secretion was reduced. T3 responsiveness was virtually abolished by 3 mmol/l sodium butyrate; higher concentrations were cytotoxic and secretion was reduced to less than 20% of basal. Lack of an effect of estradiol on SHBG secretion by HepG2 cells was confirmed. These studies suggest that T3-induced SHBG secretion by HepG2 cells is independently influenced by insulin, potentiated by dexamethasone, and modulated by PMA. Detailed molecular analysis of this model will increase our understanding of the mechanism of action of T3, specifically in human liver cells.
Effect of glucocorticoids and oestrogen on interleukin-6 production by human thyrocytes from patients with Graves' disease and toxic multinodular goitre and from HTori3 cells
Authors: Jones TH , Kennedy RL , Justice SK , Davies R
Published: January 2005

Interleukin-6 (IL-6) is a cytokine released by thyrocytes and is involved in disease processes such as autoimmune thyroid disease. The secretion of IL-6 can be stimulated by interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF), serum, TSH and agents which increase intracellular cyclic AMP levels. Antithyroid drugs such as methimazole inhibit IL-6 production by thyrocytes but the effects of glucocorticoids and oestrogen have not been investigated. The effects of dexamethasone and 17 beta-oestradiol on IL-1-, TNF-, TSH-, forskolin- and phorbol 12-myristate 13-acetate (PMA)-stimulated IL-6 release in serum-free conditions were studied in human thyrocytes derived from patients with Graves' disease and toxic multinodular goitres, and in the immortalised human thyrocyte cell line, HTori3. Dexamethasone inhibited IL-6 production under stimulated conditions. In serum-free conditions, no basal release of IL-6 was assayable. In all but one of the primary thyroid cultures, TSH did not stimulate IL-6 release above the lower detectable limit of the assay. In Graves' and multinodular goitre thyrocytes, inhibition of IL-1 (100 U/ml)-stimulated IL-6 release by dexamethasone (100 nmol/l) was 62.51% +/- 10.43 (S.E.M.), and in HTori3 cells it was 78.35% +/- 3.9. The degree of IL-1 stimulation of IL-6 release and inhibition by dexamethasone was not significantly different in thyrocytes derived from either Graves' or multinodular glands. 17 beta-Oestradiol had no effect on IL-1-stimulated IL-6 release in either primary thyroid cell culture or in HTori3 cells.
Insulin-like growth factors and their binding proteins in pleural fluid
Authors: Le Bouc Y , Bellocq A , Philippe C , Perin L , Garabedian M , Fouqueray B , Zacharias C , Cadranel J , Baud L
Published: January 2005

We investigated the expression and potential regulatory role of insulin-like growth factors (IGFs) and their specific binding proteins (BPs) in tuberculous and nontuberculous pleuritis. By using a radioimmunoassay after acid gel filtration chromatography, we found that mean concentrations of IGF-I were 211.9 +/- 20.2 microg/l and 203.2 +/- 31.1 microg/l in pleural fluid of 14 patients with tuberculous pleuritis and 9 patients with malignant pleuritis respectively. These values were near those in serum of the same patients (221.3 +/- 19.5 microg/l and 204.6 +/- 21.0 microg/l respectively). By using a specific protein-binding assay, we found that mean concentrations of IGF-II were 345.3 +/- 61.0 microg/l and 167.6 +/- 22.7 microg/l in tuberculous and malignant pleural effusions respectively. These values were significantly lower than those in serum of the same patients (628.3 +/- 79.0 microg/l, P<0.025 and 532.0 +/- 85.9 microg/l, P<0.025 respectively). Because bioavailability and bioactivity of IGFs may be regulated by their binding to IGFBPs, we studied IGFBP patterns in the pleural fluid of 6 patients with tuberculous pleuritis. As assessed by Western ligand blotting the levels of IGFBP-1 and IGFBP-2 were increased whereas those of IGFBP-3 were decreased in pleural fluid in comparison with serum. The decrease in IGFPB-3 levels reflected increased proteolysis, as assessed by Western immunoblotting. In spite of this presence of IGFBPs, IGFs could be responsible for the local biosynthesis of 1.25-dihydroxyvitamin D (1,25-(OH)2D) since pleural fluid levels of both IGF-I and IGF-II significantly correlated with those of 1,25-(OH)2D. These results indicate that IGFs are detectable in pleural fluid and may contribute to control the activity of 25-hydroxyvitamin D-1alpha hydroxylase in tuberculous pleuritis.
Allelic variations in the human growth hormone-1 gene promoter of growth hormone-deficient patients and normal controls
Authors: Wagner JK , Eble A , Cogan JD , Prince MA ,   Phillips JA, Mullis PE
Published: January 2005

OBJECTIVE: Isolated growth hormone deficiency (IGHD) type IB is suggested to be more probably due to alterations in the genes directly involved in the hypothalamo-pituitary axis and/or in the specific transcriptional regulation (cis-trans coupling) of the hGH-1 gene than to alterations in the gene itself. In this study we analyzed the hGH-1 gene promoter region for structural alterations and allelic variations. METHODS: The hGH-1 gene promoter region was analyzed by PCR, cycle sequencing and direct-blotting electrophoresis in a total of 212 individuals including 113 patients with IGHD type IB, 21 unaffected family members and 78 normal controls. RESULTS: Twenty-two sequence variation sites were identified. Of these, 14% were located around the region of -1075bp, 77% between -550bp and the translational start site (+1bp) and 9% within the first intron. Only one variation site affected a characterized cis-acting element, namely that of NF-1. Importantly, all the variations found in patients were also observed in non-affected family members as well as in normal unrelated controls. CONCLUSIONS: These findings imply that it is not a single variation within the GH-1 gene promoter, and therefore in the cis-acting elements, which causes IGHD. However, we can not exclude the possibility that combinations of variations might perturb expression. Furthermore, these data illustrate the normal heterogeneity of the GH-1 gene promoter region, a fact that has to be borne in mind whenever transcriptional studies are performed.
Immunodetection of G proteins in human pituitary adenomas: evidence for a low expression of proteins of the Gi subfamily
Authors: Ballare E , Mantovani S , Bassetti M , Lania A , Spada A
Published: January 2005

G proteins mediate signal transduction in a variety of cell systems. As the expression of these proteins has not yet been investigated in detail in human pituitary tumors, we evaluated the presence of G proteins in a series of tumors including six non-functioning adenomas, five GH-secreting adenomas, three prolactinomas and one TSH-secreting adenoma, using immunoblotting and immunohistochemistry. By immunoblotting, Gi1/2alpha was undetectable in six and barely detectable in nine tumors. A similar pattern of expression was observed by probing with the antibody to Gi3alpha, which detected a very weak band in 11 tumors and no protein in four. In contrast, using large amounts of membrane proteins (40 microg), both Gi1/2alpha and Gi3alpha were detected, although at very low levels, in the negative tumors. The low expression of these proteins appeared to be specific to tumoral tissues, as both Gi1/2alpha and Gi3alpha were abundant in normal human and rat pituitary. In all tumors, Go alpha, the two Gs alpha forms, Gq/11 and G beta were present in significant amounts. Semiquantitative analysis indicated that Gs alpha was clearly detected when 2.5 microg loaded proteins were used, whereas Gi1/2alpha and Gi3alpha were barely detected with 5 microg. By immunofluorescence, all tumors studied were markedly positive for Gs alpha that was immunolocalized at the cell periphery, whereas they showed a weak positivity for Gi1/2alpha and Gi3alpha. The study is the first to provide evidence for a low expression of Gi proteins, which are involved in the transduction of inhibitory signals, in pituitary adenomas.
Longitudinal study of fasting proinsulin in 148 siblings of patients with insulin-dependent diabetes mellitus. Study Group on Childhood Diabetes in Finland
Authors: Hartling SG , Knip M , Roder ME , Dinesen B , Akerblom HK , Binder C
Published: January 2005

OBJECTIVE: To follow proinsulin immunoreactive material (PIM) in healthy siblings from the time of diagnosis of insulin-dependent diabetes mellitus (IDDM) in the proband, for at least 2 years. DESIGN AND METHODS: The study comprised 148 siblings representing 112 families. The siblings were recruited from the nationwide 'Childhood Diabetes in Finland' study and tested for immunological markers. If a sibling was found positive for islet cell antibodies (ICA) or insulin autoantibodies (IAA), PIM sampling was extended beyond 2 years. RESULTS: Of the 148 siblings, 12 developed IDDM 3-53 months after the diagnosis in the proband. Eleven of these siblings exhibited initially normal PIM concentrations. In nine siblings, samples were available both more than 6 months and during the last 6 months before the diagnosis of IDDM; PIM concentrations increased in seven, remained unchanged in one, and decreased in one in the period up to the diagnosis of IDDM (P < 0.05). Median PIM concentration did not change significantly during the examination period of 2 years in the 136 siblings who did not contract IDDM. Constantly increased PIM concentrations were found in 12 of the 136 siblings who did not develop IDDM. These 12 siblings were all ICA negative. CONCLUSION: In healthy siblings of IDDM patients exhibiting an initially low PIM concentration, an abrupt increase in PIM seems to precede the clinical manifestation of IDDM within 0-6 months. However, there were too few patients available to close follow-up to allow calculation of any predictive value of this increase. Persistently increased PIM concentrations were present in some healthy siblings who did not develop IDDM. The reason for that finding remains unclear, but it could be associated with previous B cell damage.
Long-term vitamin D3 supplementation may have adverse effects on serum lipids during postmenopausal hormone replacement therapy
Authors: Heikkinen AM , Tuppurainen MT , Niskanen L , Komulainen M , Penttila I , Saarikoski S
Published: January 2005

OBJECTIVE: The positive short-term effects of postmenopausal hormone replacement therapy (HRT) on serum lipids are well known, but it has been suggested that they vanish with time. Cholecalciferol (vitamin D3) is widely used to prevent postmenopausal osteoporosis but the influence of vitamin D3 on serum lipids is poorly known. The long-term effects of HRT and vitamin D3 on the concentrations of serum lipids were studied in a population-based prospective 3-year study. DESIGN AND METHODS: 464 women were randomized into four treatment groups: (i) HRT (sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate), (ii) Vit D3 (vitamin D3 300 IU/day), (iii) HRT+Vit D3 (both as above), (iv) placebo (calcium lactate 500 mg/day). RESULTS: 320 women completed the study. After three years of treatment, serum concentrations of low density lipoprotein (LDL) cholesterol decreased in the HRT group (10.1%, P<0.001) and the HRT+Vit D3 group (5.9%, P=0.005), increased in the Vit D3 group (4.1%, P=0.035) but remained unchanged in the placebo group. The concentrations of total cholesterol decreased by 5.8% in the HRT group (P<0.001) and by 3.3% in the HRT+Vit D3 group (P=0.023), but did not change in the other two groups. Serum concentrations of high density lipoprotein (HDL) cholesterol decreased in the Vit D3 group (5.2%, P=0.001), HRT+Vit D3 group (3.7%, P=0.046), and the placebo group (4.5%, P=0.006) but did not change significantly in the HRT group. The HDL/LDL ratio increased in the HRT group (10.5%, P=0.006) and decreased in the Vit D3 group (10.5%, P<0.001) whereas no changes occurred in the other two groups. In addition, serum triglycerides increased similarly in all groups (14.0-18.8%, P<0.05-0.001). CONCLUSIONS: Our results confirm the positive long-term effect of HRT with sequential estradiol valerate and cyproterone acetate on serum lipid concentrations. In addition, the results suggest that vitamin D3 supplementation may have unfavorable effects on lipids in postmenopausal women. Pure vitamin D3 treatment was associated with increased serum LDL cholesterol. Furthermore, the beneficial effects of HRT on serum LDL cholesterol content were reduced when estradiol valerate was combined with vitamin D3. However, the relevance of these associations to cardiovascular morbidity remains to be established.
Anti-pancreatic autoimmunity and Graves' disease: study of a cohort of 600 Caucasian patients
Authors: Maugendre D , Verite F , Guilhem I , Genetet B , Allannic H , Delamaire M
Published: January 2005

The aim of this study was to investigate the frequencies of clinical diabetes and humoral markers of anti-pancreatic autoimmunity in a homogeneous population of 600 Caucasian patients with recently diagnosed Graves' disease (GD), in order to characterize the specific features of this group of endocrine patients among subjects at risk of diabetes. Ten were already diabetic at GD diagnosis. Among the 590 non-diabetic patients, 29 had islet cell antibodies (ICA), including 15 with low titre ICA and only 1 ICA-positive subject with a familial history of diabetes. Twenty-four patients had insulin autoantibodies, including three in association with ICA. Glutamic acid decarboxylase (GAD)/64 kDa antibodies were found in 16 of the 150 tested sera, including 13 of the 29 ICA-positive sera. Four ICA-positive patients displayed 37/40 kDa antibodies, including three in association with GAD/64 kDa antibodies. During follow-up, one of the ICA-positive patients developed insulin-dependent diabetes, 14 years after the GD diagnosis. To summarize, this anti-pancreatic autoimmunity study was focused on a large but specific and homogeneous group of subjects at risk for diabetes: recently diagnosed GD patients. This population was characterized by a high prevalence of GAD/64 kDa antibodies but also by a low frequency of evolution towards diabetes and the slowness of the process which could be due to the fact that only a minority of subjects possessed a sufficient combination of anti-pancreatic markers at the same time.
Molecular screening of both the promoter and the protein coding regions in the human ob gene in Japanese obese subjects with non-insulin-dependent diabetes mellitus
Authors: Shigemoto M , Nishi S , Ogawa Y , Isse N , Matsuoka N , Tanaka T , Azuma N , Masuzaki H , Nishimura H , Yoshimasa Y , Hosoda K , Nakao K
Published: January 2005

OBJECTIVE: Although the molecular mechanism of obesity has been poorly understood, recent studies indicate that leptin plays a critical role in regulating both food intake and body weight. Because obesity decreases the sensitivity to insulin, the human ob gene is presumed to be one of the candidate genes for non-insulin-dependent diabetes mellitus (NIDDM) associated with obesity. Although the protein coding region in the ob gene has been screened for mutations, the promoter region and the non-coding first exon have not yet been studied. We investigated the involvement of the human ob gene, especially mutations at the promoter region and the non-coding first exon, in the development of NIDDM associated with obesity. SUBJECTS: The study group comprised 60 Japanese obese subjects with NIDDM (body mass index (BMI) 43.6 > or = BMI > or = 26.4, 29.0+/-0.41 (mean+/-S.E.M.)) and 24 obese individuals with impaired glucose tolerance (IGT) (30 > or = BMI > or = 26.4, 27.1+/-0.22). METHODS: Mutations at both the promoter region and all three exons in the human ob gene were screened by the single-stranded conformational polymorphism analysis. When aberrantly migrated bands were recognized, the PCR-amplified DNA fragment was directly sequenced. RESULTS: In the protein coding region a silent mutation in the second exon was detected. The non-coding first exon and the about 100 bp 5'-flanking region of the gene which contains a proximal CCAAT/enhancer-binding protein site were screened, but no mutations were found. CONCLUSION: These results suggest that no mutations in either the promoter region at the about 100 bp 5'-flanking region of the gene, or in any of the three exons, are involved in the development of NIDDM or IGT associated with obesity.
The activity of 17alpha-hydroxylase/C17-C20 lyase in the ovaries of immature hypophysectomized rats treated with recombinant FSH combined with various doses of human chorionic gonadotropin
Authors: Okuda K , Okazaki T , Saeki M , Mori H
Published: January 2005

The activity of 17alpha-hydroxylase/C17-C20 lyase (17alpha-hydroxylase) in the ovaries and steroid hormone levels in the plasma were studied in immature hypophysectomized rats (IH-rats) treated with human recombinant follicle-stimulating hormone (rec-FSH) alone or combined with various doses of human chorionic gonadotropin (hCG). Eleven days after hypophysectomy, rats were given rec-FSH alone (total dose, 40 IU), or combined with various doses (0.1 to 10 IU in total) of hCG, twice daily for 4 days. Plasma levels of progesterone, testosterone and estradiol, and ovarian 17alpha-hydroxylase activity were measured 18 h after the last injection. Histology showed that the ovaries treated with rec-FSH alone had large antral follicles, the theca interna cells of which were small in size compared with those treated with rec-FSH combined with hCG. The activity of 17alpha-hydroxylase in the ovaries of IH-rats treated with rec-FSH alone was lower than that in the control IH-rats. It was markedly increased by treatment with rec-FSH combined with 1 or 10 IU hCG. Immunohistochemistry revealed that 17alpha-hydroxylase was localized only in the oocyte in the ovaries of control IH-rats and those treated with rec-FSH alone. When the IH-rats were treated with rec-FSH plus hCG, the number of immunopositive theca interna cells and interstitial cells, and their immunointensity were increased in an hCG dose-dependent manner. The plasma estradiol levels in the IH-rats treated with rec-FSH alone were low, but significantly higher than those in the control IH-rats, and estradiol levels were noticeably elevated in IH-rats treated with rec-FSH plus hCG. These results suggest that a synergism between hCG (LH) and FSH is essential for follicular development and steroidogenesis in the ovaries, implying paracrine effects among granulosa cells, theca cells and probably oocytes. The functional significance of 17alpha-hydroxylase in the oocytes is discussed in relation to estradiol production.
Organ-specific effects of 3,5,3'-triiodothyroacetic acid in rats
Authors: Liang H , Juge-Aubry CE , O'Connell M , Burger AG
Published: January 2005

In order to compare the effect of 3,5,3'-triiodothyroacetic acid (TRIAC) with those of triiodothyronine (T3) and thyroxine (T4), severely hypothyroid rats (n=56) were infused over 13 days with 1, 2 or 4 nmol/100 g body weight (BW) per day of T3 or 2, 4 or 8 nmol/100 g BW per day of T4 or TRIAC. The 8 nmol/100 g BW per day of T4 or TRIAC induced the same increase in resting metabolic rate, yet 4 nmol/100 g BW per day of T3 was more potent (P < 0.05). For inhibiting serum TSH levels, 2 nmol/100 g BW per day of TRIAC were significantly less active than 2 nmol/100 g BW per day of T4 or 1 nmol/100 g BW per day of T3 (TRIAC, serum TSH 35.5 +/- 5.7; T3 2.58 +/- 0.91; T4 2.12 +/- 0.59 ng/ml). At higher doses serum TSH and beta-TSH mRNA were unmeasurable. Using serum T3 levels as covariate, the action of T3 and T4 was identical on cardiac monodeiodinase type 1 (5'D1) activity and hepatic malic enzyme (Me) mRNA levels and similar for hepatic 5'D1 activity. The effect of TRIAC was compared with T3 by using increasing doses of 1, 2 and 4 nmol/100 g BW per day of T3 and 2, 4 and 8 nmol/100 g BW per day of TRIAC. ANOVA indicated that there was no major difference between the effects of the hormones since with increasing doses the response of hepatic 5'D1 mRNA levels and enzyme activity and Me mRNA remained parallel. However, when studying the effect on cardiac 5'D1 activity there was not only a difference for type of treatment (T3 > TRIAC) but this difference became greater with each increment in dose. Interestingly there was also only a small effect of TRIAC on increase in heart weight compared with T3 and T4. Brain cortex monodeiodinase type 2 (5'D2) was mainly inhibited by T4 infusions. Monodeiodinase type 3 (5'D3) was stimulated by T4, less so by TRIAC and least by T3, expressing probably the local T3 and TRIAC concentrations. In conclusion, despite apparently similar effects of TRIAC and T3 and T4 on hepatic parameters of thyroid hormone action, TRIAC differs considerably in terms of its effects on cardiac 5'D1 activity and possibly on other fundamental effects of thyroid hormones on the heart since heart weight increased significantly less with TRIAC than with T3 or T4.
Collagen metabolites in the prediction of response to GH therapy in short children
Authors: Tapanainen P , Knip M , Risteli L , Kemppainen L , Kaar ML , Risteli J
Published: January 2005

To evaluate the role of collagen metabolites in the prediction of the response to GH treatment we measured the serum concentrations of the C-terminal propeptide of type I procollagen (PICP) and the N-terminal propeptide of type III procollagen (PIIINP) with specific RIAs in 35 short children (16 boys) before and after 5 days, 5 weeks and 3 months of GH therapy. The mean age of the children was 10.3 years (range 1.9-16.4 years) and the bone age ranged from 1.2 to 12.5 years (mean 7.6 years). The initial mean relative height (RH) was -3.6 SDS (range -6.6 to -2.4 S.D.). Nineteen children were found to have GH deficiency (GHD; peak GH responses in two pharmacological tests < 10 micrograms/l), while the remaining 16 were considered to have undefined short stature (USS). The children were treated with recombinant human GH (0.1 U/kg given subcutaneously at bedtime 6-7 times/week). The increases in RHI over the first 6 and 12 months of therapy were used as response measures. There was already a significant increase (P < 0.001) in both the serum PICP and PIIINP levels at 5 days, and the concentrations continued to rise up to 3 months, PICP levels rising less than the PIIINP levels. In the whole group the RHI over 6 months correlated most strongly with the absolute PICP concentrations at 3 months (rS = 0.59; P < 0.05), while the absolute PIIINP concentrations at 3 months showed the strongest relation to the one year RHI (rS = 0.69; P < 0.001). In the GHD group the 6 month RHI was most strongly related to the absolute PICP concentration at 3 months (rS = 0.59; P < 0.05). In the USS group the absolute PICP concentrations at 3 months correlated most strongly with the one year RHI (rS = 0.82; P < 0.01). Significant correlations were also observed between the absolute PIIINP levels at 3 months and the 6 month RHI (rS = 0.60; P < 0.05) and 12 month RHI (rS = 0.76; P < 0.01) in this group. These results show that GH therapy results in an unequivocal increase in circulating concentrations of PICP and PIIINP. The serum PICP and PIIINP concentrations may be of value in the prediction of the long-term response to GH therapy.
Influence of chronic naltrexone treatment on growth hormone secretion in normal subjects
Authors: Villa P , Valle D , De Marinis L , Mancini A , Bianchi A , Fulghesu AM , Caruso A , Mancuso S , Lanzone A
Published: January 2005

OBJECTIVE: To verify if a chronic opioid blockade could affect the GH/IGF-I axis. DESIGN: We have investigated the effects of naltrexone (NTX) treatment on GH response to GHRH in normal women. METHODS: GHRH test (50 micrograms i.v.) performed in seven normal female volunteers (age 25-38 years, with a body mass index ranging from 19.8 to 23.1 kg/m2) before and after 4-weeks NTX treatment (50 mg p.o. daily). RESULTS: Basal GH, IGF-I, insulin-like growth factor binding protein-3 (IGFBP-3) plasma levels and the IGF-I/IGFBP-3 molar ratio remained unaffected by NTX. NTX significantly reduced the GH peak values (15.52 +/- 3.59 vs 4.78 +/- 0.49 micrograms/l; P < 0.01), and GH area under curve (918.93 +/- 253.96 vs 401.09 +/- 79.63 micrograms/l; P < 0.01). CONCLUSIONS: This finding suggests that the long-term opioid receptor blockade has an inhibitory role on GHRH-induced GH secretion. A central influence on neurotransmitter control of GH might be hypothesised. The inhibition of stimulated GH release, without interference with the basal level, could indicate an enhanced somatostatin secretion and/or activity. Opioids could be involved only in the regulation of GH dynamics and not in basal secretion. Nevertheless, a direct involvement of opioids at the pituitary level, which could be modified by NTX, cannot be excluded.
The GH, prolactin, ACTH and cortisol responses to Hexarelin, a synthetic hexapeptide, undergo different age-related variations
Authors: Arvat E , Ramunni J , Bellone J , Di Vito L , Baffoni C , Broglio F , Deghenghi R , Bartolotta E , Ghigo E
Published: January 2005

Hexarelin (HEX) is a synthetic growth hormone-releasing peptide (GHRP) which acts on specific receptors at both the pituitary and the hypothalamic level to stimulate GH release in an age-dependent manner. Like other GHRPs, HEX possesses also prolactin (PRL) and ACTH/cortisol-releasing activity. similar to that of human corticotropin-releasing hormone (hCRH). The mechanisms underlying the stimulatory effect of GHRPs on lactotrope and corticotrope secretion are even less clear and the influence of age on these endocrine activities of GHRPs is unknown. To clarify this point we studied the GH, PRL, ACTH and cortisol responses to the maximal effective dose of HEX (2.0 micrograms/kg i.v.) in: 12 prepubertal children (Pre-C, 8 male, 4 female, age 5.8-12.1 years); 12 pubertal normal short children (Pub-C, 5 male, 7 female, age 9.7-15.5 years, pubertal stage II-IV); 20 normal young adults (Young, 6 males, 14 females, age 23-32 years); and in 16 normal elderly people (Elderly, 5 male, 11 female, age 66-81 years). The GH response to HEX was clear in Pre-C (0-120 min area under curve, mean +/- S.E.M. 769.5 +/- 122.2 micrograms*min/l) but strikingly increased (P < 0.001) in Pub-C (1960.2 +/- 283.5 micrograms*min/l). The HEX-induced GH rise in Young (1829.7 +/- 243.1 micrograms*min/l) persisted similar to that in Pub-C, but decreased in Elderly (951.1 +/- 232.9 micrograms*min/I, P < 0.005); the latter was, in turn, similar to that in Pre-C. HEX induced a significant PRL increase which, however, showed no age-related variations, being similar in Pre-C (512.1 +/- 88.0 micrograms*min/l), Pub-C (584.0 +/- 106.0 micrograms*min/l), Young (554.9 +/- 56.0 micrograms*min/l) and Elderly (523.9 +/- 59.6 micrograms*min/l). The ACTH-releasing activity of HEX was present in Pre-C (1356.6 +/- 204.9 pg*min/ml) and was clearly enhanced (P < 0.02) in Pub-C (2253.5 +/- 242.8 pg*min/ml). The ACTH rise after HEX in Young (1258.1 +/- 141.2pg*min/ml) was lower (P < 0.02) than that in Pub-C and similar to that in Pre-C, while the ACTH response to HEX in Elderly (1786.5 +/- 340.1 pg*min/ml) showed a further trend toward increase, being similar to that in Pub-C. On the other hand, the cortisol response to HEX showed no significant age-related variations, being not different in Pre-C (7747.2 +/- 1031.6 micrograms*min/l), Pub-C (6106.0 +/- 862.9 micrograms*min/l), Young (6827.5 +/- 509.6 micrograms*min/I) and Elderly (7950.6 +/- 658.3 micrograms*min/l). In conclusion, our present data demonstrate that in humans the GH- and ACTH-releasing activities of HEX undergo different age-related variations, while its PRL-releasing activity is not dependent on age. These finding suggest that actions at different levels and/or on different receptor subtypes mediate the different age-related hormonal effects of GHRPs.
No correlation between insulin and islet amyloid polypeptide after stimulation with glucagon-like peptide-1 in type 2 diabetes
Authors: Ahren B , Gutniak M
Published: January 2005

OBJECTIVES: To examine whether glucagon-like peptide-1 (GLP-1), which has been suggested as a new therapeutic agent in type 2 diabetes, affects circulating islet amyloid polypeptide (IAPP), a B-cell peptide of potential importance for diabetes pathophysiology. DESIGN: GLP-1 was administered in a buccal tablet (400 micrograms) to seven healthy subjects and nine subjects with type 2 diabetes. Serum IAPP and insulin levels were measured before and after GLP-1 administration. RESULTS: In the fasting state, serum IAPP was 4.1 +/- 0.3 pmol/l in the controls vs 9.8 +/- 0.9 pmol/l in the subjects with type 2 diabetes (P < 0.001). IAPP correlated with insulin only in controls (r = 0.74, P = 0.002) but not in type 2 diabetes (r = 0.26, NS). At 15 min after GLP-1, circulating IAPP increased to (6.0 +/- 0.5 pmol/l in controls P = 0.009) and to 13.8 +/- 1.2 pmol/l in type 2 diabetes (P = 0.021). In both groups, serum insulin increased and blood glucose decreased compared with placebo. In controls serum IAPP increased in parallel with insulin (r = 0.79, P = 0.032), whereas in type 2 diabetes the increase in IAPP did not correlate with the increase in insulin. CONCLUSION: Type 2 diabetes is associated with elevated circulating IAPP; GLP-1stimulates IAPP secretion both in healthy human subjects and in type 2 diabetes; IAPP secretion correlates with insulin secretion only in healthy subjects and not in type 2 diabetes.
Serum leptin levels during recombinant human GH therapy in adults with GH deficiency
Authors: Janssen YJ , Frolich M , Deurenberg P , Roelfsema F
Published: January 2005

OBJECTIVE: Recent studies suggest an involvement of the obese (OB) gene and its product leptin in the regulation of body fat. Since adults with growth hormone deficiency (GHD) have a high body fat mass which can be normalized with recombinant human (rh) GH therapy, we investigated whether GH influences serum leptin directly or indirectly via its lipolytic effect. DESIGN: Fourteen adults with GHD were treated with subcutaneous injections of rhGH given every evening for 52 weeks. Serum leptin, fat mass and body fat percentage were measured at baseline and after 4 and 52 weeks of treatment. METHODS: Serum leptin was measured with a commercially available RIA. Total body water was determined by dilution of deuterium. Fat free mass was estimated by assuming a hydration of 73%. Fat mass was estimated by subtracting fat free mass from weight. RESULTS: At baseline, serum leptin levels were exponentially related to body fat percentage (r = 0.88; P < 0.0005). rhGH treatment for 4 weeks did not significantly influence serum leptin levels, whereas treatment for 52 weeks significantly decreased serum leptin levels (15.6 +/- 2.9 to 10.8 +/- 2.1 micrograms/l; P = 0.020). Fat percentage was significantly decreased after 52 weeks of treatment (37.6 +/- 2.1 to 33.8 +/- 2.5%; P < 0.0005). The decrease in serum leptin could largely be explained by the decrease in body fat percentage, whereas the relation between leptin and body fat percentage did not change. CONCLUSIONS: The influence of GH on serum leptin in indirect, via its effect on body fat percentage.
Sex-based differences in serum leptin concentrations from umbilical cord blood at delivery
Authors: Tome MA , Lage M , Camina JP , Garcia-Mayor RV , Dieguez C , Casanueva FF
Published: January 2005

Sex-based differences in serum leptin concentrations have been reported in adolescence and adulthood. To discover when such differences were generated, serum leptin concentrations were measured in umbilical cord blood from 46 healthy infants and in the mother's blood at delivery. Considering the respective body weights of the mothers and infants (68.5 +/- 1.3 kg and 3.3 +/- 0.0 kg), umbilical cord concentrations of leptin were disproportionately high in the infants (9.4 +/- 1.2 micrograms/l) compared with those in the mothers (18.7 +/- 1.3 micrograms/l). There was a wide variation in the infants leptin values (1.2 +/- 56.8 micrograms/l) that did not correlate with height, weight, cephalic circumference, or any other growth-related parameter. The most striking differences emerged when results were analysed by sex: umbilical cord concentrations of leptin in the girls (12.9 +/- 2.2 micrograms/l) were significantly (P < 0.01) greater than those in the boys (6.8 +/- 0.9 micrograms/l), although no differences in leptin concentrations were observed between the mothers who gave birth to a girl (19.5 +/- 2.2 micrograms/l) and those who gave birth to a boy (18.1 +/- 1.7 micrograms/l). The sex-based differences were not attributable to any growth-related differences between the sexes, except heavier placental weights in the girls (P < 0.007) than in the boys. These differences in leptin concentrations may reflect a sex-based difference in the regulation of leptin production by the fetal adipose tissue.
Hormonal replacement therapy affects calcitonin gene-related peptide and atrial natriuretic peptide secretion in postmenopausal women
Authors: Spinetti A , Margutti A , Bertolini S , Bernardi F , BiFulco G , degli Uberti EC , Petraglia F , Genazzani AR
Published: January 2005

OBJECTIVE: Menopause is associated with critical changes in the cardiovascular system, and the possible effect of hormonal replacement therapy (HRT) on these changes is under investigation. The aim of our study was to evaluate in postmenopausal women the effects of HRT and clonidine on the response of plasma calcitonin gene-related peptide (CGRP) and plasma atrial natriuretic peptide (ANP) to the upright posture test and the saline infusion test respectively. METHODS: CGRP and ANP levels were measured with specific radioimmunological assays and expressed in pmol/l (means +/- S.E.M). DESIGN: Postmenopausal women (age 46-53 years) (n = 18) were studied before and after 3 months of HRT (n = 13) or clonidine treatment (n = 5). RESULTS: After HRT or clonidine treatment plasma CGRP levels (14.9 +/- 1.6 and 15.9 +/- 3.8 pmol/l) were significantly higher than before (9.8 +/- 0.6 and 10.5 +/- 1.6 pmol/l) (P < 0.01). The assumption of upright posture caused no change in plasma CGRP levels before treatment, while after HRT, but not after clonidine treatment, an increase in plasma CGRP levels was observed (P < 0.01 at 5 and 20 min). Basal plasma ANP levels significantly decreased after both HRT and clonidine treatment (P < 0.01). In untreated women the saline infusion test did not induce any change in plasma ANP levels; a significant response to the test was restored after HRT but not after clonidine treatment (P < 0.01 at 90 and 120 min). CONCLUSIONS: The results show that some of the adaptive responses modified by menopausal changes are restored by HRT but not clonidine treatment, suggesting a modulatory role for sex steroid hormones in cardiovascular function and salt and water balance.
The frequency of late-onset 21-hydroxylase and 11 beta-hydroxylase deficiency in women with polycystic ovary syndrome
Authors: Sahin Y , Kelestimur F
Published: January 2005

OBJECTIVE: To determine the frequency of late-onset adrenal hyperplasia (LOCAH) due to 21-hydroxylase (21-OH) and 11 beta-hydroxylase (11 beta-OH) deficiency in women with clinical and biochemical features of polycystic ovary syndrome (PCOS). DESIGN: Eighty-three consecutively selected women with PCOS and eighteen normal women were included in the study. METHODS: Ultrasound, clinical and hormonal parameters were used to define PCOS. Basal FSH, LH, testosterone, free testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG) and cortisol levels were measured. Serum 17-hydroxyprogesterone (17-OHP) and 11-deoxycortisol (11-DOC) levels were also measured before, 30 and 60 min after a single bolus injection of 0.25 mg ACTH (1-24) at 0900 h during the mid-follicular phase of the cycle. ACTH-stimulated 17-OHP levels > 30 nmol/l were considered as the criteria of 21-OH deficiency. The diagnosis 11 beta-OH deficiency was made if the adrenal 11-DOC response to ACTH stimulation exceeded threefold the 95th percentile of controls. RESULTS: Basal serum testosterone, free testosterone, androstenedione, DHEA-S, cortisol and 11-DOC levels were significantly higher in PCOS than in control subjects. ACTH-stimulated 17-OHP (P < 0.05) and 11-DOC (P < 0.0005) levels were found to be significantly higher in patients with PCOS than in controls. Seven (8.4%) patients had an 11-DOC response to ACTH higher than threefold the 95th percentile of controls, while no patients showed evidence of 21-OH deficiency. CONCLUSIONS: We have found that 8.4% of the women with clinical and biochemical features of PCOS could be presumed to have 11 beta-OH deficiency. No patients among the women with PCOS showed evidence of 21-OH deficiency. 11 beta-OH deficiency is unexpectedly more common than 21-OH deficiency in women with PCOS.
Twenty-four-hour rhythms of plasma catecholamines and their relation to cardiovascular parameters in healthy young men
Authors: Schofl C , Becker C , Prank K , von zur Muhlen A , Brabant G
Published: January 2005

Diurnal and ultradian rhythms of plasma norepinephrine and epinephrine and their role in the regulation of cardiovascular parameters were investigated over 24 h of recumbency in a group of five men. Catecholamines were measured at 10 min intervals, and blood pressure and heart rate were recorded continuously. Norepinephrine and epinephrine rapidly fluctuated in each subject, with no obvious diurnal rhythm. Spectral analysis suggested two ultradian rhythms with periods of around 12 h and 50-100 min for both catecholamines. The pulse detection programs PULSAR and CLUSTER revealed 20-30 pulses/24 h for norepinephrine and epinephrine, with a significant correlation between the two rhythms (r = 0.63-0.80, P < 0.001). Neither the frequency nor the amplitude of these rapid fluctuations differed between day and night. Arousal in the morning caused a small increase in plasma catecholamines and getting out of bed a large increase. Thus changes in posture and activity are the main influences on the diurnal variations of plasma catecholamines reported previously, while the ultradian rhythms of sympathoadrenomedullary activity appear to be of intrinsic origin. Blood pressure and heart rate exhibited a diurnal rhythm with a nightly decrease. Arousal and rising from bed increased blood pressure and heart rate significantly. Although the amplitude of the rapid fluctuations of plasma catecholamines at times exceeded those caused by postural changes in the morning, when both plasma norepinephrine and epinephrine levels correlated highly with all cardiovascular parameters, correlations were not significant during recumbency. Thus the intrinsic ultradian fluctuations of plasma catecholamines appear not to be involved in the control of cardiovascular parameters during recumbency, and the increase in blood pressure and heart rate in the morning appears to be controlled by direct sympathetic neural input to the heart and vasculature in response to changes in activity and posture rather than by an endogenous surge of plasma catecholamines.
Menin mutations in patients with multiple endocrine neoplasia type 1
Authors: Mayr B , Apenberg S , Rothamel T , von zur Muhlen A , Brabant G
Published: January 2005

Multiple endocrine neoplasia type 1 (MEN-1) is a familial cancer syndrome with parathyroid, pituitary and enteropancreatic tumors. The disease phenotype segregates with markers on chromosome 11q13. Very recently a new gene was cloned from this region and was found to carry mutations in 14 of 15 unrelated MEN-1 patients. The gene was termed menin and is predicted to code for a tumor suppressor protein of 610 amino acids, but its precise function is totally unknown. To confirm this finding we used PCR from genomic DNA and direct sequencing to analyze exons 2 through 10 of the menin gene in eight patients from four pedigrees with MEN-1 syndrome or an affected relative. We identified four different heterozygous mutations, three of them are novel: one nonsense mutation, one large deletion of 32 bp and two insertions, all of them located in exon 2. Our results confirm that patients with MEN-1 carry mutations in the menin gene.