bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Granulosa Cells Use High Density Lipoprotein Cholesterol for Steroidogenesis1
Authors: Azhar Salman , Tsai Louisa , Medicherla Satyanarayana , Chandrasekher Yasmine , Giudice Linda , Reaven Eve
Published: January 2014

This study examines the ability of human high density lipoproteins (HDL3) to deliver cholesteryl esters to human granulosa cells and describes the selective cholesterol pathway by which this occurs. Luteinized cells obtained from subjects undergoing in vitro fertilization-embryo transfer procedures were incubated with native HDL3 (or radiolabeled or fluorescently labeled HDL cholesteryl esters) to determine whether cells from humans (in which HDL is not the primary circulating lipoprotein species) can nevertheless interiorize and appropriately process cholesteryl esters for steroidogenesis. The results indicate that hormone-stimulated granulosa cells actively and efficiently use human HDL-derived cholesterol for progesterone production. More than 95% of the mass of HDL cholesteryl esters entering cells does so through the nonlysosomal (selective) pathway, i.e. cholesteryl esters released from HDL are taken up directly by the cells without internalization of apoproteins. Once internalized, the cholesteryl esters are either hydrolyzed and directly used for steroidogenesis or stored in the cells as cholesteryl esters until needed. The utilization of the internalized cholesteryl esters is a hormone-regulated event; i.e. luteinized human granulosa cells internalize and store large quantities of HDL-donated cholesteryl esters when available, but further processing of the cholesteryl esters (hydrolysis, reesterification, or use in steroidogenesis) does not occur unless the cells are further stimulated to increase progesterone secretion.
A New Polymorphic Restriction Site in the Human 11β-Hydroxysteroid Dehydrogenase Type 2 Gene
Authors: Smolenicka Z. , Bach E. , Schaer A. , Liechti-Gallati S. , Frey B.M. , Frey F.J. , Ferrari P
Published: January 2014

ABTRACT

The 11β-hydroxysteroid dehydrogenase type II enzyme (11βHSD2) inactivates glucocorticoids in the kidney and thus prevents glucocorticoids from occupying the non-selective mineralocorticoid receptor in epithelial tissues. Mutants in the HSD11B2 gene have been found to cause the syndrome of apparent mineralocorticoid excess, a rare autosomal recessive disease characterized by severe hypertension. Thus, this locus could also be an ideal candidate involved in the etiology of primary hypertension. We identified a polymorphism in exon 3 characterized by a GAG to GAA transition at codon 178, with the loss of an Alu I restriction site and analyzed it in an association study using end-stage renal disease patients, diabetic or essential hypertensive patients and control subjects. Two-hundred eighty nine subjects and patients were analyzed; the genotype was determined by amplification of genomic DNA and subsequent digestion with Alu I restriction enzyme. The prevalence of the Alu I allele was 8.6% in healthy control subjects (n = 116). This prevalence was lower (χ2 P = 0.035 vs. controls) than the 18.0% in a group of renal transplant patients (n = 61). The corresponding values for patients with diabetes mellitus (n = 25), hypertension (n = 41) and patients on dialysis (n = 46) were 4.0%, 4.8% and 4.3%, respectively. There was no correlation between blood pressure and the marker in non-ESRD subjects. These data indicate the presence of a polymorphic marker in exon 3 of the HSD11B2 gene; this marker is associated with end-stage renal disease but not with essential hypertension in humans.
Analysis of Loss of Heterozygosity on Chromosome 11 and Infrequent Inactivation of the MEN1 Gene in Sporadic Pituitary Adenomas1
Authors: Tanaka Chisato , Kimura Takehiko , Yang Peng , Moritani Maki , Yamaoka Takashi , Yamada Shozo , Sano Toshiaki , Yoshimoto Katsuhiko , Itakura Mitsuo
Published: January 2014

abstract

To investigate the role of tumor suppressor genes in sporadic pituitary adenomas, we first analyzed loss of heterozygosity on 11q13 with microsatellite analysis in 31 tumors. Loss of heterozygosity on 11q13 was detected in 1 mixed GH/PRL adenoma, and the somatic 22-bp deletion of the multiple endocrine neoplasia type 1 (MEN1) gene encoding menin was detected in this tumor. Trisomy 11 suggested by the decreased mean allelic ratios of 66% or 65% for 16 or 13 microsatellite markers, respectively, in 2 of 31 pituitary adenomas was confirmed by interphase fluorescence in situ hybridization. Screening for mutations of the MEN1 gene did not find mutations with PCR-single strand conformation polymorphism analysis in other pituitary adenomas retaining heterozygosity on 11q13.

Based on these, it is concluded that inactivation of the MEN1 gene comprises a rare etiology for tumorigenesis of the pituitary gland, and that trisomy 11 or another gene(s) may contribute to the pathogenesis of sporadic pituitary adenomas.
Parathyroid MEN1 Gene Mutations in Relation to Clinical Characteristics of Nonfamilial Primary Hyperparathyroidism1
Authors: Carling Tobias , Correa Pamela , Hessman Ola , Hedberg Jakob , Skogseid Britt , Lindberg Daniel , Rastad Jonas , Westin Gunnar , Åkerström Göran
Published: January 2014

abstract

Biochemical signs and severity of symptoms of primary hyperparathyroidism (pHPT) differ among patients, and little is known of any coupling of clinical characteristics of nonfamilial pHPT to genetic abnormalities in the parathyroid tumors. Mutations in the recently identified MEN1 gene at chromosome 11q13 have been found in parathyroid tumors of nonfamilial pHPT. Using microsatellite analysis for loss of heterozygosity (LOH) at 11q13 and DNA sequencing of coding exons, the MEN1 gene was studied in 49 parathyroid lesions of patients with divergent symptoms, operative findings, histopathological diagnosis, and biochemical signs of nonfamilial pHPT. Allelic loss at 11q13 was detected in 13 tumors, and 6 of them demonstrated previously unrecognized somatic missense and frameshift deletion mutations of the MEN1 gene. Many of the detected mutations would most likely result in a nonfunctional menin protein, consistent with a tumor suppressor mechanism. Clinical and biochemical characteristics of HPT were apparently unrelated to the presence or absence of LOH and the MEN1 gene mutations. However, the demonstration of LOH at 11q13 and MEN1 gene mutations in small parathyroid adenomas of patients with slight hypercalcemia and normal serum PTH levels suggest that altered MEN1 gene function may also be important for the development of mild sporadic pHPT.
Gestational Changes in the Levels of Transforming Growth Factor-β1 (TGFβ1) and TGFβ Receptor Types I and II in the Human Myometrium1
Authors: Hatthachote Panadda , Morgan Joanna , Dunlop William , Europe-Finner G. Nicholas , Gillespie James I.
Published: January 2014

abstract

As term approaches, a number of key proteins [contraction-associated proteins (CAPs)] are expressed within the human myometrium that are essential for the activation of powerful coordinated contractions during labor. The nature of the signals that switch on the synthesis of CAPs in vivo is not known. The ryanodine-sensitive intracellular Ca2+ release channel (RyR2) is a CAP whose expression in vitro is activated by transforming growth factor-β (TGFβ). The present experiments were performed to determine whether TGFβ and TGFβ receptors are present in the human myometrium at term and to explore the idea that they might form part of a signaling system in vivo. TGFβ receptor types I and II, but not III, were demonstrated in myometrial smooth muscle in tissue taken from nonpregnant, pregnant nonlaboring, and spontaneous laboring women. Western blotting was used subsequently to determine the relative expression of TGFβ receptor types I and II. Using nonpregnant myometrium as a baseline control the levels of expression of receptor types I and II were significantly increased by 168 ± 19% (n = 6) and 162 ± 22% (n = 7) in pregnant nonlaboring myometrium. In spontaneous laboring myometrium the levels of TGFβ receptor type I and II expression were 93 ± 12% (n = 6) and 85 ± 11% (n = 7), respectively, compared to nonpregnant control values and were significantly lower than levels in pregnant nonlaboring tissues. The total TGFβ1 levels in the myometrial tissues were 334 ± 10, 534 ± 73, and 674 ± 106 pg/g tissue wet wt in nonpregnant, pregnant nonlaboring, and spontaneous laboring myometrium (n = 3 in each group), respectively. Thus, the TGFβ signaling system appears to be up-regulated in the myometrium before the onset of parturition. The apparent loss of receptors in the spontaneous laboring samples in the presence of elevated total levels of TGFβ may be indicative of agonist-induced receptor down-regulation. These observations support the idea that cytokines, in particular TGFβ1, may play a role in the normal processes that prepare the myometrium for parturition at term.
Insulin-Like Growth Factor Binding Protein-3: A Novel Biomarker for the Assessment of the Synthetic Capacity of Hepatocytes in Liver Cirrhosis
Authors: Shaarawy Mohamed , Fikry Mohamed Amin , Massoud Baher Aly , Lotfy Samar
Published: January 2014

The liver is the major source of circulating insulin-like growth factor binding protein-3 (IGFBP-3). Because the hepatic tissue is deranged in cirrhotic patients, we measured serum IGFBP-3 concentrations by two-site immunoradiometric assay in sera from 37 cirrhotic patients with different stages of hepatic dysfunction. These were compared with IGFBP-3 levels from 11 healthy controls. Serum IGFBP-3 levels in patients with chronic liver disease were significantly lower than those of the control group (P < 0.0005). The mean percent decrease in cases of early liver cirrhosis, cirrhosis without, and cirrhosis with ascites were 44%, 59%, and 82% respectively, indicating that serum IGFBP-3 levels decrease as the severity of hepatic dysfunction increases.

Moreover, the decrease was more pronounced in cases with hyperbilirubinemia, elevated serum transaminases, hypoalbuminemia, and prolonged prothrombin time. There was a significant positive correlation between serum IGFBP-3 and serum albumin, as well as a significant negative correlation between serum IGFBP-3 and prothrombin time. These results indicate the close correlation of IGFBP-3 levels to worsening of hepatic functions. The determination of serum IGFBP-3 level is a clinically useful marker for the assessment of the synthetic capacity of hepatocytes in cirrhotic patients and an early predictor of impending hepatic dysfunction as well. .
Effects of Recombinant Human Insulin-Like Growth Factor I Administration on Growth Hormone (GH) Secretion, Both Spontaneous and Stimulated by GH-Releasing Hormone or Hexarelin, a Peptidyl GH Secretagogue, in Humans1
Authors: Ghigo E. , Gianotti L. , Arvat E. , Ramunni J. , Valetto M. R. , Broglio F. , Rolla M. , Cavagnini F. , Müller E. E.
Published: January 2014

The negative feedback exerted by insulin-like growth factor I (IGF-I) on GH secretion occurs at the pituitary, as well as the hypothalamic level, via stimulation of SS and/or inhibition of GHRH release. In fact, recombinant human IGF-I (rhIGF-I) administration inhibits basal GH secretion, at least in fasted humans, though its effect on the GH response to GHRH is still controversial. GH secretagogues (GHS) are peptidyl and nonpeptidyl molecules that act on specific receptors at the pituitary and/or the hypothalamic level. Contrary to GHRH, the GH-releasing activity of GHS is strong, reproducible, and even partially refractory to inhibitory influences such as exogenous somatostatin. We studied the effects of rhIGF-I administration (20μ g/kg sc at 0 min) on GH secretion, either spontaneous or stimulated by GHRH (2 μg/kg iv at +180 min) or Hexarelin (HEX, 2.0 μg/kg iv at+ 180 min), a GHS, in eight normal young women (age, mean ± sem, 28.3 ± 1.2 yr; body mass index, 20.1± 0.5 kg/m2). rhIGF-I administration increased IGF-I levels (peak vs. baseline: 420.3 ± 30.5 vs. 274.4 ± 25.3 μg/L, P < 0.05) within the physiological range from +120 to +300 min. No variation in glucose or insulin levels was recorded. rhIGF-I did not reduce spontaneous GH secretion [areas under curves (AUC)0–300 min 140.6± 66.3 vs. 114.6 ± 32.1 μg/L·h], whereas it inhibited the GH response to both GHRH (AUC180–300 min 447.7 ± 159.4 vs. 715.9 ± 104.3 μg/L·h, P < 0.05) and HEX (620.3 ± 110.4 vs. 1705.9 ± 328.9 μg/L·h, P < 0.03). The percent inhibitory effect of rhIGF-I on the GH response to GHRH (41.7 ± 12.8%) was lower than that on the response to HEX (57.7 ± 11.0%). In fact, the GH response to GHRH alone was clearly lower than that to HEX alone (P < 0.05), whereas the GH responses to GHRH and HEX were similar after rhIGF-I. Our findings show that the sc administration of low rhIGF-I doses inhibits the GH response to GHRH and, even more, that to HEX; whereas, at least in this experimental design in fed conditions, it does not modify the spontaneous GH secretion. Because GHS generally show partial refractoriness to inhibitory inputs, including exogenous somatostatin, the present results point toward a peculiar sensitivity of GHS to the negative feedback action of IGF-I.
Serum Leptin Levels Correlate with Growth Hormone Secretion and Body Fat in Children*
Authors: Fors Hans , Matsuoka Hisafumi , Bosaeus Ingvar , Rosberg Sten , Wikland Kerstin Albertsson , Bjarnason Ragnar
Published: January 2014

The aim of this study was to investigate the relationship among GH secretion, leptin concentrations, and body composition measured with x-ray absorptiometry (DXA) in children. In total, 71 children were investigated, 51 males and 20 females. Their mean chronological age was 10.8 yr (range, 6.2–17.7 ys), and their mean height (sd) was −2.1 (0.63) sd scores. Their mean weight for height sd scores (WHSDS) was 0.2 (1.18). Body composition was investigated using DXA. Blood samples were taken for analysis of leptin, insulin-like growth factor I (IGF-I), IGF-binding protein-3, and 24-h GH secretion. A positive correlation was found between leptin and total body fat (r = 0.83; P< 0.0001) and when fat was expressed as a percentage of body weight (r = 0.86; P < 0.0001). There were significant (P < 0.0001) relationships between leptin and WHSDS (r = 0.45) and between leptin and body mass index (r = 0.69). A significant gender difference in leptin levels was found, but this disappeared after adjustment for body fat, as measured by DXA. There were significant (P< 0.001) inverse correlations between leptin and the AUCb for GH (r = −0.41), leptin, and GHmax (r =− 0.38), where AUCb is the area under the curve above the calculated baseline, and GHmax is the maximum peak during the 24-h GH profile (percent fat and AUCb for GH, r =− 0.43; percent fat and GHmax, r = −0.39). In a multiple stepwise forward regression analysis with leptin as the dependent variable, the percent trunk fat accounted for 77.7% of the leptin variation. With AUCb for GH as the dependent variable, the percent trunk fat accounted for 20.3% of the variation. With GHmax as the dependent variable, the percent trunk fat accounted for 18.8% of the variation, IGF-binding protein-3 for another 8.5%, and the percentage of fat from arms and legs for another 4.4%.

We demonstrated a strong positive correlation between leptin levels and body fat, a significant negative correlation between leptin levels and GH secretion, and a significant negative correlation between body fat and GH secretion. We have also shown that specific regional fat depots have different relationships with leptin and particular markers of GH secretion.
A Possible Role of Immunoglobulin E in Patients with Hyperthyroid Graves’ Disease
Authors: Sato Akira , Takemura Yoshihiro , Yamada Takashi , Ohtsuka Hiromi , Sakai Hideki , Miyahara Yasuhiro , Aizawa Toru , Terao Akira , Onuma Soshin , Junen Kazuhiro , Kanamori Akira , Nakamura Yutaka , Tejima Eizaburo , Ito Yoshiharu , Kamijo Keiichi
Published: January 2014

To investigate the possible participation of immunoglobulin E (IgE) in the autoimmune process of Graves’ disease, incidence of elevation of serum IgE level, TSH receptor antibody (TRAb), and thyroid status were studied in 66 patients with hyperthyroid Graves’ disease, 54 patients with Hashimoto’s thyroiditis, 19 patients with bronchial asthma, and 15 patients with pollen allergy. In hyperthyroid Graves’ patients, elevation of serum IgE levels (≥170 U/mL) was found in 19 of 66 patients (29%), 11 of whom had hereditary and/or allergic conditions. Elevations of serum IgE levels were found in 63% of patients with bronchial asthma and in 40% of patients with pollen allergy. Mean values of serum IgE were the same in patients with hyperthyroid Graves’ disease and with bronchial asthma. During methimazole treatment TRAb decreased without fluctuation of IgE levels in both groups. The decrease in TRAb was significantly greater in patients with normal IgE than in patients with IgE elevation. After prednisone administration, reduction in TRAb was greater in patients with normal IgE than that in patients with IgE elevation.

High incidence of IgE elevation in hyperthyroid Graves’ disease and slower reduction in TRAb in association with IgE elevation suggest a difference in the autoimmune processes in Graves’ disease with and without elevation of IgE.
Two Polymorphisms in the Peroxisome Proliferator-Activated Receptor-γ Gene Are Associated with Severe Overweight among Obese Women*
Authors: Valve R. , Sivenius K. , Miettinen R. , Pihlajamäki J. , Rissanen A. , Deeb S. S. , Auwerx J. , Uusitupa M. , Laakso M.
Published: January 2014

Peroxisome proliferator-activated receptor-γ (PPARγ) is a nuclear receptor that regulates adipocyte differentiation. Variations in the PPARγ gene may affect the function of the PPARγ and, therefore, body adipocity. We investigated the frequencies of the Pro12Ala polymorphism in exon B and the silent CAC478CAT polymorphism in exon 6 of the PPARγ gene and their effects on body weight, body composition, and energy expenditure in obese Finns. One hundred and seventy obese subjects [29 men and 141 women; body mass index (BMI), 35.7 ± 3.8 kg/m2; age, 43 ± 8 yr; mean ± sd) participated in the study. The frequencies of the Ala12 allele in exon B and CAT478 allele in exon 6 were not significantly different between the obese and population-based control subjects (0.14 vs. 0.13 and 0.19 vs. 0.21, respectively). The polymorphisms were associated with increased BMI [Pro12Pro, 34.5 ± 3.8; Pro12Ala, 34.8 ± 3.1; Ala12Ala, 39.2± 4.6 kg/m2 (P = 0.011); CAC478CAC, 34.5 ± 3.8; CAC478CAT, 34.5 ± 3.3; CAT478CAT, 37.7 ± 4.1 kg/m2 (P = 0.046)]. In addition, the women with both Ala12Ala and CAT478CAT genotypes (n = 5) were significantly more obese compared with the women having both Pro12Pro and CAC478CAC genotypes (n = 85; BMI, 40.6 ± 3.3 vs. 34.4 ± 3.9 kg/m2; P = 0.001), and they had increased fat mass (46.8 ± 9.1 vs. 36.8 ± 7.5 kg; P = 0.005). In conclusion, the Pro12Ala and CAC478CAT polymorphisms in the PPARγ gene are associated with severe overweight and increased fat mass among obese women.
Food-Dependent Cushing’s Syndrome: Possible Involvement of Leptin in Cortisol Hypersecretion*
Authors: Pralong François P. , Gomez Fulgencio , Guillou Louis , Mosimann François , Franscella Sebastiano , Gaillard Rolf C.
Published: January 2014

Stimulation of cortisol secretion by food intake has been implicated in the pathogenesis of some cases of ACTH-independent Cushing’s syndrome, via an aberrant response of the adrenal glands to gastric inhibitory polypeptide (GIP). We report here a novel case of food-dependent Cushing’s syndrome in a patient with bilateral macronodular adrenal hyperplasia. In this patient we were able to confirm a paradoxical stimulation of cortisol secretion by GIP in vivo as well as in vitro on dispersed tumor adrenal cells obtained at surgery. In addition to GIP, in vitro stimulation of these cultured tumor adrenal cells with leptin, the secreted product of the adipocyte, induced cortisol secretion. By comparison, no such stimulation was observed in vitro in adrenal cells obtained from another patient with bilateral macronodular adrenal hyperplasia and Cushing’s syndrome that did not depend on food intake, in tumor cells obtained from a solitary cortisol-secreting adrenal adenoma, and in normal human adrenocortical cells.

These results demonstrate that as in previously described cases of food-dependent Cushing’s syndrome, GIP stimulated cortisol secretion from the adrenals of the patient reported here. Therefore, they indicate that such a paradoxical response probably represents the hallmark of this rare condition. In addition, they suggest that leptin, which normally inhibits stimulated cortisol secretion in humans, participated in cortisol hypersecretion in this case. Further studies in other cases of food-dependent Cushing’s syndrome, however, will be necessary to better ascertain the pathophysiological significance of this finding.
Aromatase Deficiency Caused by a Novel P450arom Gene Mutation: Impact of Absent Estrogen Production on Serum Gonadotropin Concentration in a Boy1
Authors: Deladoëy Johnny , Flück Christa , Bex Marie , Yoshimura Noriko , Harada Nobuhiro , Mullis Primus E.
Published: January 2014

We identified a new point mutation in the CYP19 gene responsible for aromatase (P450arom) deficiency in a 46,XY male infant with unremarkable clinical findings at birth. This boy is homozygote for a 1-bp (C) deletion in exon 5 of the aromatase gene causing a frame-shift mutation. The frame-shift results in a prematurely terminated protein that is inactive due to the absence of the functional regions of the enzyme.

Aromatase deficiency was suspected prenatally because of the severe virilization of the mother during the early pregnancy, and the diagnosis was confirmed shortly after birth. Four weeks after birth, the baby boy showed extremely low levels of serum estrogens, but had a normal level of serum free testosterone; in comparison with the high serum concentration of androstenedione at birth, a striking decrease occurred by 4 weeks postnatally. We previously reported elevated basal and stimulated FSH levels in a female infant with aromatase deficiency in the first year of life. In contrast, in the male infant, basal FSH and peak FSH levels after standard GnRH stimulation tests were normal. This finding suggests that the contribution of estrogen to the hypothalamic-pituitary gonadotropin-gonadal feedback mechanism is different in boys and girls during infancy and early childhood. In normal girls, serum estradiol concentrations strongly correlate with circulating inhibin levels, and thus, low inhibin levels may contribute to the striking elevation of FSH in young girls with aromatase deficiency. In contrast, estradiol levels are physiologically about a 7-fold lower in boys than in girls, and serum inhibin levels remain elevated even though levels of FSH, LH, and testosterone are decreased.
Fasting Remnant Lipoprotein Cholesterol and Triglyceride Concentrations Are Elevated in Nondiabetic, Insulin-Resistant, Female Volunteers1
Authors: Abbasi Fahim , McLaughlin Tracey , Lamendola Cindy , Yeni-Komshian Helen , Tanaka Akira , Wang Tao , Nakajima Katsuyuki , Reaven Gerald M.
Published: January 2014

This study was initiated to test the hypothesis that plasma concentrations of remnant lipoproteins would be higher after an overnight fast in insulin-resistant compared to insulin-sensitive volunteers. Forty-three healthy nonobese women were studied, divided into insulin-resistant (n = 21) and insulin-sensitive (n = 22) groups on the basis of their steady state plasma glucose (SSPG) concentration at the end of a 180-min infusion of octreotide acetate, insulin, and glucose. Under these conditions, steady state plasma insulin concentrations are similar in all subjects (∼60μ U/mL), and the higher the SSPG concentrations, the more insulin resistant the individual. By selection, mean (±sem) SSPG concentrations were significantly higher (P < 0.001) in the insulin-resistant group (210 ± 7 vs. 78 ± 3 mg/dL). In addition, the insulin-resistant group had higher triglycerides (198 ± 27 vs. 101 ± 12 mg/dL; P < 0.005) and lower high density lipoprotein cholesterol (48 ± 4 vs. 60 ± 4 mg/dL; P < 0.05) concentrations. Finally, insulin resistance was associated with higher remnant lipoprotein particle concentrations of cholesterol (7.2 ± 0.8 vs. 4.4 ± 0.3; P < 0.005) and triglycerides (22.2 ± 3.4 vs. 8.5 ± 1.0; P < 0.001). All of these differences were seen despite the fact that the two groups were similar in terms of age and body mass index. These results identify additional abnormalities in lipoprotein metabolism that may contribute to the increased risk of coronary heart disease seen in insulin-resistant, nondiabetic subjects (syndrome X).
Reduced Retinal Vascularization in Children with Growth Hormone Deficiency1
Authors: Hellström Ann , Svensson Elisabeth , Carlsson Björn , Niklasson Aimon , Albertsson-Wikland Kerstin
Published: January 2014

The neovascularization in diabetic retinopathy is believed to involve locally produced angiogenic factors. In addition, there are indications that GH may influence retinal vascularization. To investigate the role of GH in retinal vascularization, we examined the retinal vascular pattern in children with congenital GH deficiency. Retinal vessel morphology was evaluated by digital image analysis of ocular fundus photographs in 39 children (5 girls and 34 boys, aged 3.6–18.7 yr) with congenital GH deficiency, and it was compared to that of 100 healthy controls. Twenty children had received GH treatment (0.1 IU/kg daily). All children were born at term, and none of the children had any clinical signs of ocular disease or reduced vision. Children with GH insufficiencies, regardless of whether they were treated with GH, had a significantly lower number of vascular branching points than the reference group (P < 0.0001). Thirty-three percent of the GH-insufficient individuals had a number of vascular branching points less than or equal to the fifth percentile of the reference group. The reduced retinal vascularization observed in children with congenital GH deficiency suggests that GH may be of importance for angiogenesis.
Regulation of Soluble Insulin-Like Growth Factor II/Mannose 6-Phosphate Receptor in Human Serum: Measurement by Enzyme-Linked Immunosorbent Assay1
Authors: Costello Michael , Baxter Robert C. , Scott Carolyn D.
Published: January 2014

The soluble form of the insulin-like growth factor II/mannose 6-phosphate (IGF-II/M6-P) receptor has been detected in serum from a variety of mammalian species. We report the development of a highly sensitive quantitative human IGF-II/M6-P receptor immunoassay. Antibodies raised to receptor purified from a human hepatoma cell line by phosphomannan affinity chromatography were used to develop a specific enzyme-linked immunosorbent assay. In this assay, the serum level of soluble receptor for healthy adult subjects was 0.70 ± 0.23 mg/L. We have shown that soluble receptor is developmentally regulated, with levels in infant (1.12 ± 0.28 mg/L) and prepubertal (1.18 ± 0.6 mg/L) subjects dropping by 40% during adolescence (0.73 ± 0.61 mg/L) and remaining constant throughout adulthood. Further, the receptor is gestationally regulated, with a highly significant association between gestational age and maternal serum receptor levels (r = 0.947; P < 0.0001). Noninsulin-dependent diabetes mellitus (0.98 ± 0.25 mg/L) and insulin-dependent diabetes mellitus (0.98 ± 0.25 mg/L) mildly elevated soluble receptor levels, whereas end-stage renal failure (0.75 ± 0.23 mg/L) and acromegaly (0.79 ± 0.25 mg/L) did not affect receptor levels. Additionally, we have shown that soluble receptor is present in amniotic fluid, but at a 100-fold lower concentration than serum levels. The ability to quantitate soluble IGF-II/M6-P receptor levels in serum and other fluids provides a valuable tool that will help to further elucidate the role of the receptor in human physiology and disease states.
Locus Heterogeneity of Autosomal Dominant Osteopetrosis (ADO)1
Authors: White Kenneth E. , Koller Daniel L. , Takacs Istvan , Buckwalter Kenneth A. , Foroud Tatiana , Econs Michael J.
Published: January 2014

Autosomal dominant osteopetrosis (ADO), is a heritable disorder that results from a failure of osteoclast-mediated bone resorption. The etiology of the disorder is unknown. A previous linkage study of one Danish family mapped an ADO locus to chromosome 1p21. We have studied two families from Indiana with ADO. The present study sought to determine if the ADO gene in these families was also linked to chromosome 1p21. We used six microsatellite repeat markers, which demonstrated linkage to the 1p21 ADO locus in the Danish study, to perform linkage analysis in the new kindreds. Multipoint analysis excluded linkage of ADO to chromosome 1p21 (logarithm of the odds score < −7.00) in both families. In addition, no haplotype segregated with the disorder in either family. In summary, the present investigation ruled out linkage of ADO to chromosome 1p21 in two families from Indiana. Our results demonstrate that there is locus heterogeneity of this disorder; therefore, mutations in at least two different genes can give rise to the ADO phenotype.
Medroxyprogesterone Acetate and Dexamethasone Are Competitive Inhibitors of Different Human Steroidogenic Enzymes1
Authors: Lee Tim C. , Miller Walter L. , Auchus Richard J.
Published: January 2014

Medroxyprogesterone acetate (MPA), a widely used progestin, can suppress the hypothalamic-pituitary-gonadal axis but can also directly inhibit gonadal steroidogenesis; the success of MPA as a treatment for gonadotropin-independent sexual precocity derives from its direct action on steroidogenic tissues. Dexamethasone, a widely used glucocorticoid, can suppress the hypothalamic-pituitary-adrenal axis, but its potential effect directly on the adrenal is unclear. Previous reports suggested that these two drugs may act on the initial steps in the rodent steroidogenic pathway; therefore, we investigated their abilities to inhibit the first three human enzymes in steroidogenesis: the cholesterol side-chain cleavage enzyme (P450scc), the 17α-hydroxylase/17,20-lyase (P450c17), and type II 3β-hydroxysteroid dehydrogenase/isomerase (3βHSDII). We found no effect of either drug on P450scc in intact human choriocarcinoma JEG-3 cells. Using microsomes from yeast expressing human P450c17 or microsomes from human adrenals, we found that dexamethasone inhibited P450c17 with a Ki of 87 μmol/L, which is about 1000 times higher than typical therapeutic concentrations, but that MPA has no detectable action on P450c17. Using microsomes from yeast expressing human 3βHSDII, we found that this enzyme has indistinguishable apparent Km values of 5.2–5.5 μmol/L and similar maximum velocities of 0.34–0.56 pmol steroid/min·μg microsomal protein for the three principal endogenous substrates, pregnenolone, 17-hydroxypregnenolone, and dehydroepiandrosterone. In this system, MPA inhibited 3βHSDII with a Ki of 3.0 μmol/L, which is near concentrations achieved by high therapeutic doses of 5–20 mg MPA/kg·day. These data establish the mechanism of action of MPA as an inhibitor of human steroidogenesis, and are in contrast with the results of earlier studies indicating that MPA inhibited both P450c17 and 3βHSD in rat Leydig cells. These studies establish the“ humanized yeast” system as a model for studying the actions of drugs on human steroidogenic enzymes and suggest that 3βHSDII may be an appropriate target for pharmacological interventions in human disorders characterized by androgen excess or sex steroid dependency.
Serum Leptin Concentrations and Expression of Leptin Transcripts in Placental Trophoblast with Advancing Baboon Pregnancy1
Authors: Henson Michael C. , Castracane V. Daniel , O’Neil Jennifer S. , Gimpel Terry , Swan Kenneth F. , Green Amy E. , Shi Wenliang
Published: January 2014

Leptin is a polypeptide hormone originally thought to be produced exclusively by adipocytes. Recently, however, both leptin messenger ribonucleic acid (mRNA) and leptin protein were identified in human placental trophoblast cells, suggesting a potential role in primate pregnancy. In the present study, venous blood samples were collected at 5-day intervals during gestation from baboons (Papio sp), an established model for the study of human pregnancy, as well as from nonpregnant baboons, and leptin concentrations were determined by RIA. Additionally, placental villous tissue was collected upon cesarean delivery at early (days 60–62; n = 5), mid (days 98–102; n= 5), and late (days 159–167; n = 5) gestation (term = ∼184 days), and leptin mRNA was quantitated by competitive RT-PCR. Finally, in situ hybridization was employed to localize transcripts to specific placental cell types. Results determined that maternal leptin levels (mean ± sem), which were dramatically greater (P < 0.01) than those in nonpregnant cycling baboons (1.4 ± 0.1 ng/mL), increased (P < 0.005) with gestational age from 63.6 ± 10.4 ng/mL on day 60 of gestation to 157.8 ± 16.1 near term. Levels declined to those found in cycling baboons by 15 days postdelivery. In contrast to maternal leptin concentrations, placental leptin mRNA decreased (P < 0.02) with advancing pregnancy, as transcript abundance declined approximately 8-fold from early to late gestation. Maternal peripheral leptin concentrations were positively correlated (r = 0.66; P < 0.001) whereas placental leptin mRNA levels were negatively correlated (r= −0.64; P < 0.01) with gestational age. Expression of leptin mRNA transcripts, as evidenced by RT-PCR in villous tissue, was localized principally within syncytiotrophoblast by in situ hybridization.

In summary, changes in maternal peripheral leptin concentrations and placental leptin mRNA abundance that occur commensurate with advancing gestational age may imply evolving roles for the polypeptide with advancing primate pregnancy. In this capacity, localization of leptin transcripts within the baboon syncytiotrophoblast suggests the potential for autocrine or paracrine interactions within this endocrinologically active tissue. Finally, both the similarities in leptin ontogeny in baboon and human pregnancy and the singular enhancement of maternal leptin levels inherent throughout baboon gestation emphasize the potential of this nonhuman primate model for the study of leptin action in the maternal-fetoplacental unit.
Effects of Intranasal 17β-Estradiol on Bone Turnover and Serum Insulin-Like Growth Factor I in Postmenopausal Women
Authors: Garnero Patrick , Tsouderos Yannis , Marton Istvan , Pelissier Clara , Varin Claire , Delmas Pierre D.
Published: January 2014

Estrogen therapy, using either oral or transdermal routes, decreases bone turnover and prevents postmenopausal bone loss. It has been suggested that oral and transdermal 17β-estradiol (E2) may have different effects on serum insulin-like growth factor I (IGF-I), a potent bone-forming growth factor. In this study we investigated the effects of a new route of administration, the intranasal E2 spray (S21400), on bone turnover and circulating IGF-I and IGF-binding protein-3 (IGFBP-3). Four hundred and twenty early postmenopausal women (<5 yr since menopause; mean age, 52 yr) were enrolled in a 3-month, double blind, placebo-controlled study of four doses of intranasal E2 (100, 200, 300, and 400μ g/day), two doses of oral E2 valerate (1 or 2 mg/day), and placebo. One hundred and twelve women were further treated for 12 months with intranasal E2 (300 μg/day, i.e. the dose that has been shown to be adequate for the majority of postmenopausal women). Markers of bone resorption (urinary type I collagen C telopeptides) and formation [serum osteocalcin, serum type I collagen N-terminal extension propeptide (PINP), and serum bone alkaline phosphatase (BAP)] were measured at baseline, 1 month, 3 months, and 15 months. Serum IGF-I and IGFBP-3 were measured at baseline, 1 month, and 3 months. Urinary type I collagen C telopeptides decreased significantly in all active treatment groups as soon as 1 month (P < 0.001 vs. placebo) and continued to decrease at 3 months with a dose effect for intranasal E2. Serum osteocalcin and PINP did not change at 1 month for oral E2 (1 and 2 mg), but decreased significantly at 3 months. In contrast, formation markers increased significantly at 1 month for the two highest doses of intranasal E2 (P < 0.01 vs. placebo for osteocalcin and BAP) and did not decrease at 3 months. Oral E2 induced a marked decrease in circulating IGF-I as early as 1 month, which was amplified at 3 months (−29% and −32% for 1 and 2 mg, respectively), whereas no significant change from placebo was observed for intranasal E2 during the 3-month period. Changes in circulating IGF-I correlated significantly (P < 0.01) with changes in osteocalcin, PINP, and BAP at 3 months. Oral and intranasal E2 did not induce any significant change from placebo in serum IGFBP-3 at both 1 and 3 months. After 1 yr of treatment with intranasal E2 (300μ g/day), both resorption and formation markers decreased, reaching the levels in premenopausal women, regardless of the type of treatment during the first 3 months.

We conclude that E2 administered by this new nasal route normalizes bone turnover to premenopausal levels. The delayed decrease in bone formation observed with intranasal E2 compared to oral E2 may be related to different effects on serum IGF-I levels.
Leptin Is Released from the Human Brain: Influence of Adiposity and Gender1
Authors: Wiesner Glen , Vaz Mario , Collier Greg , Seals Douglas , Kaye David , Jennings Gary , Lambert Gavin , Wilkinson Dominic , Esler Murray
Published: January 2014

Leptin, a 16-kDa circulating protein primarily derived from adipocytes, is an important factor in the regulation of appetite and energy expenditure. Using simultaneous arterio-venous blood sampling, several organs were assessed with regard to their individual roles in leptin metabolism in healthy male and female subjects constituting a range of body mass indices. Plasma leptin levels were unchanged after passage through the hepatosplanchnic and forearm circulations. In contrast, concentrations in the renal vein were consistently lower than those in the renal artery (−15%; P < 0.005), indicating net extraction, whereas the brain was observed to be a net leptin releaser. Concentrations in the internal jugular vein were significantly higher than arterial levels in lean females (change, 3.0 ± 1.2 ng/mL; P < 0.02) and in obese males (body mass index, >28 kg/m2), but not lean (change, 2.3 ± 2.3 vs. 0.1 ± 0.1 ng/mL, respectively; P < 0.05), indicating a probable influence of both gender and adiposity on brain leptin release. An attempt to grossly localize the site of brain release by using cerebral venous scans to distinguish between jugular venous drainage from cortical and subcortical brain areas revealed no region-specific secretion. These data raise the possibility that the brain is a nonadipose source of leptin. In addition, the higher level of brain release observed in females may contribute to the well documented gender differences in overall plasma leptin levels.
Coculture of Human Embryos with Autologous Human Endometrial Epithelial Cells in Patients with Implantation Failure1
Authors: Simón Carlos , Mercader Amparo , Garcia-Velasco Juan , Nikas George , Moreno Carlos , Remohí Jose , Pellicer Antonio
Published: January 2014

We have developed a coculture system with autologous human endometrial epithelial cells (AEEC) that retained many features of human endometrial epithelium. Implantation failure (IF; >3 previous cycles failed with 3–4 good quality embryos transferred) is a distressing condition in which 2-day embryo transfer repetition is the routine option. The objective of this study was to investigate the basics and to evaluate prospectively the clinical value of embryo coculture on AEEC and blastocyst transfer with their own oocytes [in vitro fertilization (IVF) patients] or with donated oocytes (oocyte donation patients) compared to a routine day 2 embryo transfer for patients with IF. Scanning electron microscopy and mouse embryo assays demonstrate that EEC from fertile and IF patients were morphologically and functionally similar; similar findings were observed in EEC obtained from fresh or frozen endometria. Clinically, 168 IVF cycles were performed in 127 patients with 3.8 ± 0.2 previously failed cycles, and 80 cycles were performed in 57 patients undergoing oocyte donation with 3.0 ± 0.2 previously failed cycles. Twenty IVF patients and 15 ovum donation patients with 3 previously failed cycles in whom a 2-day embryo transfer was performed were used as controls. In 88% of ovum donation cycles, at least 2 blastocysts were available for transfer, with 60.1% blastocyst formation; 2.2 ± 0.1 blastocysts were transferred/cycle, and 36 pregnancies (determined by fetal cardiac activity) were obtained (32.7% implantation and 54.5% pregnancy rates). In 168 IVF cycles, 8.1 ± 0.2 embryos/cycle started coculture, resulting in 49.2% blastocyst formation; 2.3 ± 0.2 blastocysts were transferred/cycle, and 29 clinical pregnancies were obtained (11.8% implantation and 20.2% pregnancy rates). Fifteen cycles were canceled (9%). In oocyte donation patients with IF undergoing 2-day embryo transfer, implantation and pregnancy rates were significantly lower (4.5% and 13.3%; P < 0.01) than with coculture; however, in IVF patients with IF, results with day 2 transfer (10.7% and 35%) were similar to those with coculture. The present study demonstrates that coculture of human embryos with AEEC and blastocyst transfer is safe, ethical, and effective and constitutes a new approach to improve implantation in patients with IF undergoing ovum donation, but not in IVF patients.
Low Dose Hexarelin and Growth Hormone (GH)-Releasing Hormone as a Diagnostic Tool for the Diagnosis of GH Deficiency in Adults: Comparison with Insulin-Induced Hypoglycemia Test1
Authors: Gasperi M. , Aimaretti G. , Scarcello G. , Corneli G. , Cosci C. , Arvat E. , Martino E. , Ghigo E.
Published: January 2014

GH deficiency (GHD) in adults must be shown by provocative testing of GH secretion. Insulin-induced hypoglycemia (ITT) is the test of choice, and severe GHD, treated with recombinant human GH replacement, is defined by a GH peak response to ITT of less than 3 μg/L. GHRH plus arginine (ARG) is a more provocative test and is as sensitive as ITT provided that appropriate cut-off limits are assumed. GH secretagogues are a family of peptidyl and nonpeptidyl GH-releasing molecules that strongly stimulate GH secretion and, even at low doses, truly synergize with GHRH. Our aim was to verify the diagnostic reliability of the hexarelin (HEX; 0.25 μg/kg, iv) and GHRH (1 μg/kg, iv) test for the diagnosis of adult GHD. To this goal, in the present study we 1) defined the normal ranges of the GH response to GHRH+HEX in a group of normal young adult volunteers (NS; n = 25; 18 men and 7 women; age, 28.5 ± 0.6 yr) and in 11 of them verified its reproducibility in a second session, and 2) compared the GH response to GHRH+HEX with that to ITT in a group of normal subjects (n = 33; 12 men and 21 women; age, 34.1 ± 1.5 yr) and hypopituitaric adults with GHD (n = 19; 10 men and 9 women; age, 39.9 ± 2.2 yr; GH peak <5 μg/L after ITT). The GH response to GHRH+ARG was also evaluated in all GHD and in 77 normal subjects (40 men and 37 women; age, 28.1 ± 0.6 yr). The mean GH peak after GHRH+HEX in NS was 83.6 ± 4.5 μg/L; the third and first percentile limits of the normal GH response were 55.5 and 51.2 μg/L, respectively). The GH response to GHRH+HEX in NS showed good intraindividual reproducibility. In GHD the mean GH peak after GHRH+HEX (2.6 ± 0.7 μg/L) was similar to that after GHRH+ARG (3.6 ± 1.0 μg/L), and both were higher (P < 0.001) than that after ITT (0.6± 0.1 μg/L); the GH responses to GHRH+HEX were positively associated with those to ITT and GHRH+ARG. Analyzing individual GH responses, 100% had severe GHD after ITT (GH peak, <3 μg/L). After GHRH+HEX all GHD had GH peaks below the third percentile limit of normality appropriate for this test (i.e. 55.5 μg/L). Thirteen of 19 (68.4%) GHD subjects had GH peaks below 3 μg/L after GHRH+HEX but all 19 (100%) had GH peaks below the first percentile limit of normality (i.e. 51.2 μg/L). The GH responses to GHRH+HEX were highly concordant with those after GHRH+ARG. In conclusion, the present results define normal limits of the GH response to stimulation with low dose HEX+GHRH in normal adults and show that this test is as sensitive as ITT for the diagnosis of adult GHD provided that appropriate cut-off limits are considered.
Comparison of Metabolic Deterioration between Insulin Analog and Regular Insulin after a 5-Hour Interruption of a Continuous Subcutaneous Insulin Infusion in Type 1 Diabetic Patients1
Authors: Guerci Bruno , Meyer Laurent , Sallé Agnès , Charrié Anne , Dousset Brigitte , Ziegler Olivier , Drouin Pierre
Published: January 2014

An interruption of continuous sc insulin infusion (CSII) of the insulin analog lispro should result in a more rapid metabolic deterioration of type 1 diabetic patients because of its pharmacokinetic characteristics. We analyzed the metabolic changes occurring during a 5-h interruption of CSII and the 5 h after restarting the pump in 10 type 1 diabetic patients. The study was a randomized, cross-over, open label design comparing insulin analog [Lispro (LP)] and regular insulin [Velosuline (VE)]. Plasma glucose, free insulin, glucagon,β -hydroxybutyrate (β-OHB), and nonesterified fatty acids (NEFA) were measured every hour from 0700 h (time zero) to 1700 h (600 min). After stopping CSII, the plasma glucose level was significantly higher in the LP group than in the VE group (P < 0.05–0.01). The plasma free insulin level decreased significantly with the two treatments, but was significantly lower with LP than with VE (P < 0.05–0.01). Plasma NEFA increased more rapidly and was significantly higher in the LP group than in the VE group (P < 0.01–0.05). Plasma β-OHB increased earlier with LP, but was not statistically different between the treatments. After restarting the pump, plasma glucose decreased with LP, but continued to increase with VE, and the plasma free insulin peak occurred earlier and was greater with LP than with VE (P < 0.05). Plasma NEFA and β-OHB levels decreased significantly with the two treatments, but more dramatically with LP treatment. Thus, a short interruption of Lispro in CSII is associated with an earlier, greater metabolic deterioration, but Lispro corrected this metabolic deterioration more effectively.