bluuebunny/crossref_metadata_2025 huggingface dataset:
Follicle-Stimulating Hormone and Luteinizing Hormone/Chorionic Gonadotropin Stimulation of Vascular Endothelial Growth Factor Production by Macaque Granulosa Cells from Pre- and Periovulatory Follicles1
Authors: Christenson Lane K. , Stouffer Richard L.
Published: January 2014

Granulosa cells in the ovulatory follicle express messenger ribonucleic acid encoding vascular endothelial growth factor (VEGF), an agent that may mediate the neovascularization of the developing corpus luteum, but it is not known whether luteinizing granulosa cells synthesize and secrete VEGF during the periovulatory interval. Studies were designed to evaluate the effects of an in vivo gonadotropin surge on VEGF production by macaque granulosa cells (study 1) and to test the hypothesis that gonadotropins act directly on granulosa cells to regulate VEGF production (study 2). Monkeys received a regimen of exogenous gonadotropins to promote the development of multiple preovulatory follicles. Nonluteinized granulosa cells (i.e. preovulatory; NLGC) and luteinized granulosa cells (i.e. periovulatory; LGC) were aspirated from follicles before and 27 h after an ovulatory gonadotropin bolus, respectively. Cells were either incubated for 24 h in medium with or without 100 ng/mL hCG (study 1) or cultured for 6 days in medium with or without 100 ng/mL hCG or 0.1, 1, 10, and 100 ng/mL of recombinant human LH (r-hLH) or r-hFSH (study 2). Culture medium was assayed for VEGF and progesterone. In study 1, LGC produced 8-fold greater levels of VEGF than NLGC (899 ± 471 vs. 111 ± 26 pg/mL, mean ± sem; P < 0.05). In vitro treatment with hCG increased (P < 0.05) VEGF production by NLGC to levels that were not different from the LGC incubated under control conditions. In vivo bolus doses of r-hCG (100 and 1000 IU) and r-hFSH (2500 IU) were equally effective in elevating granulosa cell VEGF production. In study 2, in vitro treatment with r-hFSH, r-hLH, and hCG markedly increased (P< 0.05) VEGF and progesterone production by the NLGC in a dose- and time-dependent manner. By comparison, the three gonadotropins (100 ng/mL dose) only modestly increased VEGF and progesterone production by LGC. These experiments demonstrate a novel role for the midcycle surge of gonadotropin (LH/CG or FSH) in primates to promote VEGF production by granulosa cells in the periovulatory follicle. Further, the data demonstrate that FSH-like as well as LH-like gonadotropins directly stimulate VEGF synthesis by granulosa cells.
Programmed Cell Death in Human Ovary Is a Function of Follicle and Corpus Luteum Status*
Authors: Yuan Wei , Giudice Linda C.
Published: January 2014

Although extensive investigation on follicular apoptosis (programmed cell death) has been conducted in the infraprimate ovary, there is little information regarding apoptosis and its relationship to follicular status in the human. In this study, apoptosis was investigated in 116 human ovarian follicles (primordial to dominant) and 5 corpora lutea from a total of 27 premenopausal women. Follicles and corpora lutea were evaluated for the presence of DNA fragmentation, characteristic of apoptosis, by two methods: in situ hybridization using 3′ end-labeling of DNA with digoxigenin-labeled nucleotides and subsequent digoxigenin antibody and peroxidase staining, and/or biochemical analysis of low molecular weight DNA laddering. Follicle functional status was evaluated by determining follicle sizes and follicular fluid androgen/estrogen (A/E) ratios. No apoptosis was observed in 67 primordial, primary, or secondary follicles. Positive staining for DNA fragmentation was found in a few granulosa cells in 0.1- to 2-mm follicles, whereas abundant staining in granulosa was detected in 2.1- to 9.9-mm follicles. In contrast, no DNA fragmentation was detected in dominant follicles (10–16 mm). The frequency of apoptosis in follicles was calculated to be 37% in 0.1- to 2-mm follicles, 50% in 2.1- to 5-mm follicles, and 27% in 5.1- to 9.9-mm follicles. Abundant low molecular weight DNA laddering was only found in androgen-dominant follicles and not in estrogen-dominant follicles. Positive staining for DNA fragmentation and low molecular weight DNA laddering were observed in degenerating but not healthy-appearing corpora lutea. In the former, DNA fragmentation was found primarily in large luteal cells. These data suggest that follicular atresia in human ovary results from normal programmed cell death and primarily occurs in the granulosa cell layers of the early antral and <10-mm antral follicles primarily. Furthermore, because apoptosis occurs as early as the 200-mm stage, follicle selection may begin as early as the initial formation of the antrum. The results also suggest that degeneration of the corpus luteum occurs by apoptotic mechanisms.
Serum Leptin Concentrations in Caucasian and African-American Girls1
Authors: Wong William W. , Nicolson Margery , Stuff Janice E. , Butte Nancy F. , Ellis Kenneth J. , Hergenroeder Albert C. , Hill Rebecca B. , Smith Elliot O.
Published: January 2014

Because African-American girls are heavier, taller, and mature earlier than Caucasian girls, we hypothesized that the serum leptin concentration differs between the two groups. Serum leptin concentrations were measured by immunoassay in 12-h fasted blood samples collected from 79 Caucasian and 57 African-American girls between 8 and 17 yr of age. Body composition was measured by dual-energy x-ray absorptiometry, sexual maturity by physical examination, and physical fitness by treadmill testing. Serum leptin concentrations were positively correlated (P < 0.01) with maturation, body fatness, and insulin and were higher (6.6 ng/mL, P < 0.01) in the African-American girls after adjusting for age. The difference remained significant (P < 0.01) but was reduced to 3.2 ng/mL after controlling for differences in maturation, fat mass, and physical fitness. The higher serum leptin levels might play an important role in the accelerated growth and sexual maturation of African-American girls.
Fibronectin Is Required to Prevent Thyroid Cell Apoptosis through an Integrin-Mediated Adhesion Mechanism1
Authors: Vitale Mario , Di Matola Tiziana , Fenzi Gianfranco , Illario Maddalena , Rossi Guido
Published: January 2014

Apoptosis or programmed cell death occurs in a wide variety of cell types when adhesion to extracellular matrix (ECM) is denied. Invasion and metastasis by tumor cells involve the loss of normal cell-ECM contacts and require independence from such control mechanisms. We studied whether the immortalized thyroid cell line TAD-2 is a model suitable to investigate thyroid cell-ECM interaction, and we analyzed the role of integrin-fibronectin (FN) interaction in apoptosis. Adhesion, spreading, and cytoskeleton organization in TAD-2 cultured cells were dependent upon integrin-FN interaction. Cell spreading and cytoskeletal organization were coupled to deposition of insoluble FN induced by serum. Expression of integrin-FN receptors was demonstrated by flow cytofluorometry with specific antibodies, and strong integrin-dependent adhesion was demonstrated by attachment assays to immobilized FN. Apoptosis, occurring in different culture conditions, was determined by cell morphology and DNA electrophoretic analysis and quantitated by flow cytometry in propidium iodide-stained cells. Thyroid cells underwent apoptosis in the presence of serum when adhesion was prevented by specific peptides that inhibit integrin binding to FN (RGD-containing peptides) or by coating the culture plates with agar. In serum-free cultures, apoptosis was prevented by insoluble FN immobilized on the plates, but not by soluble FN. These results suggest that the TAD-2 cell line is a good model to study thyroid cell-ECM interaction, that FN, assembled into insoluble matrix, is required for cytoskeletal organization and to prevent thyroid cell apoptosis, and that integrin-mediated adhesion is involved in this process.
How Is Whole Body Protein Turnover Perturbed in Growth Hormone-Deficient Adults?1
Authors: Hoffman David M. , Pallasser Robert , Duncan Mark , Nguyen Tuan V. , Ho Ken K. Y.
Published: January 2014

Adult patients with GH deficiency have reduced lean body mass (LBM), muscle mass, and muscle strength, suggesting an underlying abnormality of protein metabolism. As acute GH administration has previously been reported to decrease protein oxidation and increase protein synthesis in GH-deficient (GHD) adults, we investigated whether the converse might occur in untreated GH deficiency by undertaking studies of whole body protein turnover in 10 GHD and 13 normal subjects using a 3-h primed constant infusion of 1-[13C]leucine. Dual energy x-ray absorptiometry was used to quantify LBM and fat mass (FM).

In normal subjects, LBM was the major, independent determinant of leucine appearance (Ra; r = 0.80; P = 0.0009), leucine oxidation (r = 0.81; P = 0.0008), and leucine incorporation into protein (r = 0.75; P = 0.003). However, in an analysis of covariance, FM was also a significant independent determinant of leucine Ra (P = 0.002) and leucine incorporation into protein (P = 0.003). After correcting for LBM and FM, GHD patients had significantly reduced rates of leucine Ra (109.9 ± 4.4 vs. 125.5 ± 3.7 μmol/min, respectively; P = 0.02) and leucine incorporation into protein (87.0 ± 3.9 vs. 100.3 ± 3.3 mmol/min; P = 0.02) compared to normal subjects. There was no significant difference in the corrected rates of leucine oxidation between the two groups (22.9 ± 1.3 vs. 25.2± 1.0, GHD vs. normal; P = 0.20).

In summary, GHD adults have reduced rates of protein synthesis and protein breakdown, but normal rates of irreversible oxidative loss; these findings are discordant with what was predicted from the acute changes in protein metabolism observed with GH administration. We conclude that normalization of protein oxidation may be a homeostatic mechanism that operates to constrain protein loss in GHD adults.
Food-Dependent Cushing’s Syndrome: Characterization and Functional Role of Gastric Inhibitory Polypeptide Receptor in the Adrenals of Three Patients1
Authors: Lebrethon M. C. , Avallet O. , Reznik Y. , Archambeaud F. , Combes J. , Usdin T. B. , Narboni G. , Mahoudeau J. , Saez J. M.
Published: January 2014

In the present work, the presence of gastric inhibitory polypeptide (GIP) receptors and their functional role in the adrenal cells of three patients with food-dependent Cushing’s syndrome were studied. RT-PCR and in situ hybridization studies demonstrated the presence of GIP receptor in the adrenals of the three patients. The presence of this receptor was also demonstrated in two human fetal adrenals, but not in two normal adult human adrenals or in the adrenals of one patient with nonfood-dependent Cushing’s syndrome. Freshly isolated cells from patient adrenals responded in a dose-dependent manner to the steroidogenic action of both ACTH and GIP, whereas cells from normal adrenals responded only to ACTH. Treatment of cultured normal adrenal cells with ACTH, but not with GIP, increased the messenger ribonucleic acid (mRNA) levels of cholesterol side-chain cleavage cytochrome P-450, P450c17, and 3β-hydroxysteroid dehydrogenase, whereas both hormones enhanced these mRNAs in patients’ adrenal cells, although the effects of ACTH were greater than those of GIP. Moreover, pretreatment with ACTH enhanced the steroidogenic responsiveness of both normal and patient adrenal cells, whereas GIP caused homologous desensitization, and this was associated with a marked reduction of GIP receptor mRNA levels, as demonstrated by RT-PCR and in situ hybridization. Finally, both ACTH and GIP inhibited DNA synthesis in one patient’s adrenal cells, whereas in normal adrenal cells only ACTH had this effect. In conclusion, the present data demonstrate that ectopic expression of functional GIP receptors is the main cause of food-dependent Cushing’s syndrome.
Simulated Microgravity Increases β-Adrenergic Lipolysis in Human Adipose Tissue1
Authors: Barbe P. , Galitzky J. , De Glisezinski I. , Riviere D. , Thalamas C. , Senard J. M. , Crampes F. , Lafontan M. , Berlan M.
Published: January 2014

The effect of a sustained decrease in sympathetic nervous activity, achieved through 5-day head-down bed rest (HDBR), on the β-adrenergic lipolytic activity of sc adipose tissue was studied in eight healthy men. The in situ β-adrenoceptor (AR) sensitivity was studied using the microdialysis method. Local perfusion of increasing concentrations of isoprenaline showed an increased β-AR sensitivity to lipolysis (assessed by extracellular glycerol concentration) and to vascular tone (assessed by the ethanol clearance). The adrenergic sensitivity of isolated adipocytes was studied in vitro. Basal lipolysis and the response to nonselective (isoprenaline) or selective (dobutamine, terbutaline, and CGP 12177) β-AR agonists were increased after HDBR as was the lipolytic effect of dibutyryl cAMP. When data were expressed as a percentage of the dibutyryl cAMP effect to rule out the postreceptor events, basal and lipolytic responses toβ -AR agonists where similar before and during HDBR. Theα 2-AR-mediated antilipolytic effects of adrenaline were not modified. Lymphocyte β-AR number was unchanged during HDBR. Our results demonstrate that a sustained sympathoinhibition induces an increase in the lipolytic β-adrenergic response in adipose tissue and suggest that this hypersensitization is linked to an increase in the postreceptor steps of the lipolytic cascade in the adipocyte rather than to changes in β-adrenoceptors.
Apoptosis and Fas Expression in Human Fetal Membranes1
Authors: Runić Radmila , Lockwood Charles J. , LaChapelle Linda , Dipasquale Bruno , Demopoulos Rita I. , Kumar Asok , Guller Seth
Published: January 2014

Apoptosis (i.e. programmed cell death) plays a key role in maintaining reproductive function in the ovary, mammary and prostate glands, uterus, and testis. The purpose of the present report was to determine, based on biochemical and morphological parameters, whether cells in human fetal membranes undergo apoptosis and express Fas (CD95), a cell surface receptor that mediates apoptosis. Using the terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling immunohistochemical technique, apoptotic nuclei were identified in amnion epithelial, chorionic trophoblast, and decidua parietalis cell layers of human fetal membranes at term. Electron microscopy of fetal membranes revealed ultrastructural characteristics in amnion epithelium and chorion trophoblast cell layers consistent with apoptosis, including condensation of chromatin along the periphery of the nucleus and nuclear shrinkage. The apoptotic index (percentage of terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling-positive nuclei of the total nuclei) ranged from 8–29% in amnion epithelial, chorionic trophoblast, and decidual cell layers from women at 23–30, 31–36, and 37–42 weeks gestation. The apoptotic index was statistically greater in the 37–42 week group than in the 23–30 week group in chorionic trophoblast (P < 0.05) and decidual cell (P < 0.01) layers. In contrast, the apoptotic index in the amnion epithelial cell layer was statistically greater (P < 0.05) in the 23–30 week group than in the 31–36 week group, suggesting that apoptosis may be independently regulated in amnion epithelial, chorionic trophoblast, and decidual cell types. Based on the importance of Fas in mediating apoptosis, we investigated whether Fas was expressed by human fetal membrane cells. Immunohistochemical staining of fetal membranes with anti-Fas antibody localized Fas in amnion epithelial, chorionic trophoblast, and decidua parietalis cell layers. A 266-bp band corresponding to the cytoplasmic domain of Fas was detected in samples of amnion, chorion, decidua, and placenta by RT-PCR. Northern blotting revealed a molecular weight of approximately 1.9 kilobases for Fas messenger ribonucleic acid in amniotic tissue. These data suggest that apoptosis and Fas signaling may play a role in remodeling of fetal membrane architecture across gestation.
Heterogenous Dopamine D2 Receptor Subtype Messenger Ribonucleic Acid Expression in Clinically Nonfunctioning Pituitary Adenomas1
Authors: Renner Ulrich , Arzberger Thomas , Pagotto Uberto , Leimgruber Susanne , Uhl Eberhard , Müller Adolf , Lange Manfred , Weindl Adolf , Stalla Günter K.
Published: January 2014

Little is known about differences in the expression, localization, and function of the two dopamine D2 receptor subtypes, D2short and D2long (D2s and D2l), in either normal or adenomatous pituitary. We investigated the messenger RNA (mRNA) expression of the D2 receptor (D2R) subtypes in clinically nonfunctioning pituitary adenomas by in situ hybridization using subtype-specific oligonucleotides. The five normal pituitaries studied expressed similar ratios of D2R subtypes mRNA with a predominant expression of the D2l isoform. In 2 of 18 clinically inactive adenomas no D2R mRNA was found, whereas in 16 a heterogenous expression of D2R isoforms was observed. Six adenomas expressed only the D2l and 2 adenomas only the D2s subtype mRNA; the remaining 8 expressed extremely varying proportions of the two subtypes. The D2R was found only in a subset of the nonfunctioning adenoma cells. In gonadotropin-immunopositive adenomas, the D2R was mainly localized in LH- and FSH-immunopositive cells. Probably because of the heterogenous D2R subtype expression, suppression of cell proliferation was observed in only 3 of 9 adenoma cell cultures in which the growth inhibitory effect of bromocriptine was studied. Although there is some evidence that the presence of the D2s receptor subtype favors the growth inhibitory response to bromocriptine, further studies with a larger number of inactive adenomas are needed to confirm this speculation.
Alterations in Growth and Body Composition During Puberty: III. Influence of Maturation, Gender, Body Composition, Fat Distribution, Aerobic Fitness, and Energy Expenditure on Nocturnal Growth Hormone Release1
Authors: Roemmich James N. , Clark Pamela A. , Mai Vu , Berr Stuart S. , Weltman Arthur , Veldhuis Johannes D. , Rogol Alan D.
Published: January 2014

We examined the relationships among gender, sexual maturation, four-compartment model estimates of body composition, body fat distribution (magnetic resonance imaging for abdominal visceral fat and anthropometrics), aerobic fitness, basal and total energy expenditure, and overnight GH release in an ultrasensitive chemiluminescence assay in healthy prepubertal and pubertal boys (n = 18 and 11, respectively) and girls (n = 12 and 18, respectively). Blood samples were withdrawn every 10 min from 1800–0600 h to determine the area under the serum GH-time curve (AUC), sum of the GH peak heights (Σ GH peak heights), and the mean nadir GH concentration. GH release was greater in the pubertal than prepubertal subjects due to an increase in Σ GH peak heights (43.8 ± 3.6 vs. 24.1 ± 3.5 ng·mL−1, P = 0.0002) and mean nadir (1.7 ± 0.2 vs. 0.7 ± 0.2 ng·mL−1, P = 0.0002), but not peak number (4.3 ± 0.2 vs. 4.5 ± 0.2). The girls had a greater Σ GH peak heights (39.0 ± 3.5 vs. 28.8 ± 3.6 ng·mL−1, P = 0.05) and mean nadir concentration (1.4 ± 0.2 vs. 0.9 ± 0.2 ng·mL−1, P = 0.05) than the boys. Significant inverse relationships existed between Σ GH peak heights (r = −0.35, P = 0.06) or mean nadir (r = −0.39, P = 0.04) and four-compartment percent body fat for all boys but not for all girls or when combining all subjects. For all girls, significant inverse relationships existed between Σ GH peak heights (r = −0.39, P = 0.03) or mean nadir (r = −0.37, P = 0.04) and waist/hip ratio. Similar inverse relationships in all boys or all subjects were not significant. Forward stepwise regression analysis determined that bone age (i.e. maturation, primary factor) and gender were the significant predictors of AUC, Σ GH peak heights, and mean nadir. The influence of maturation reflects rising sex steroid concentrations, and the gender differences appear to be because of differences in estradiol concentrations rather than to body composition or body fat distribution.
The Metabolic Syndrome and Insulin-Like Growth Factor I Regulation in Adolescent Obesity1
Authors: Attia Naja , Tamborlane William V. , Heptulla Rubina , Maggs David , Grozman Aida , Sherwin Robert S. , Caprio Sonia
Published: January 2014

Although low GH levels are commonly seen in obese adults and children, the effects of obesity on the insulin-like growth factor (IGF)/IGF-binding protein (IGFBP) system have not been established. As GH and IGF-I normally increase during adolescence, we investigated the effects of obesity on circulating total and free IGF-I levels and IGFBP-1, -2, and -3 in 19 obese adolescents [14 ± 1 yr old; body mass index (BMI), 34 ± 3], 20 lean adolescents (14 ± 1 yr old; BMI, 23 ± 0.5), and 10 lean adults (22 ± 0.7 yr; BMI, 22 ± 0.7). Fasting plasma insulin levels were significantly greater in obese adolescents than in either lean group, whereas circulating IGFBP-1 levels were suppressed in an inverse relationship to basal insulin (r = −0.49; P < 0.01). Low IGFBP-1 levels were associated with normal to increased free IGF-I levels in obese adolescents, even though total IGF-I values were lower than those in lean adolescents. Basal GH and IGFBP-3 levels were also lower in obese vs. lean adolescents. Basal IGFBP-1 levels were markedly reduced in obese adolescents (14 ± 3 ng/mL) vs. those in adolescents and adults. No further suppression of IGFBP-1 levels was observed in the obese group during a two-step 8 and 40 mU/m2 insulin clamp. In contrast, IGFBP-1 levels were promptly lowered in lean adults. Basal IGFBP-2 levels were significantly lower in both groups of adolescents vs. lean adults (P < 0.05), and IGFBP-2 levels did not change during euglycemic hyperinsulinemia. These data suggest that the compensatory hyperinsulinemia that characterizes adolescent obesity chronically suppresses levels of IGFBP-1, and low IGFBP-1 concentrations may serve to increase the bioavailability of free IGF-I, which may, in turn, contribute to lower circulating GH, total IGF-I, and IGFBP-3 concentrations.
Development of a Health-Related Quality-of-Life Questionnaire (PCOSQ) for Women with Polycystic Ovary Syndrome (PCOS)1
Authors: Cronin L. , Guyatt G. , Griffith L. , Wong E. , Azziz R. , Futterweit W. , Cook D. , Dunaif A.
Published: January 2014

Objective: To develop a self-administered questionnaire for measuring health-related quality of life (HRQL) in women with polycystic ovary syndrome (PCOS).

Methods: We identified a pool of 182 items potentially relevant to women with PCOS through semistructured interviews with PCOS patients, a survey of health professionals who worked closely with PCOS women, and a literature review. One hundred women with PCOS completed a questionnaire in which they told us whether the 182 items were relevant to them and, if so, how important the issue was in their daily lives. We included items endorsed by at least 50% of women in the analysis plus additional items considered crucial by clinicians and an important subgroup of patients in a factor analysis. We chose items for the final questionnaire taking into account both item impact (the frequency and importance of the items) and the results of the factor analysis.

Results: Over 50% of the women with PCOS labelled 47 items as important to them. Clinicians chose 5 additional items from the infertility domain, 4 of which were identified as important by women who were younger, less educated, married, and African-American. The Cattell’s Scree plot from a factor analysis of these 51 items suggested 5 factors that made intuitive sense: emotions, body hair, weight, infertility, and menstrual problems. We chose the highest impact items from these 5 domains to construct a final questionnaire, the Polycystic Ovary Syndrome Questionnaire (PCOSQ), which includes a total of 26 items and takes 10–15 minutes to complete.

Conclusions: We have used established principles to construct a questionnaire that promises to be useful in measuring health-related quality of life. The questionnaire should be tested prior to, or concurrent with, its use in randomized trials of new treatment approaches.
Tumor Necrosis Factor-α in Sera of Obese Patients: Fall with Weight Loss
Authors: Dandona Paresh , Weinstock Ruth , Thusu Kuldip , Abdel-Rahman Ehad , Aljada Ahmad , Wadden Thomas
Published: January 2014

abstract

In view of the recent demonstration that obesity in animals and humans is associated with an increase in tumor necrosis factor-α (TNFα) expression, that this expression falls with weight loss, and that TNFα may specifically inhibit insulin action, the possibility that TNFα may be a mediator of insulin resistance has been raised. We have undertaken this study to investigate whether serum TNFα concentrations are elevated in obese subjects, whether they fall after weight loss, and whether this fall parallels the fall in insulin release after glucose challenge. Obese patients (age range: 25–54, weight mean ± sd: 96.4 ± 13.8 kg, body mass index: 35.7 ± 5.6 kg/m2) were started on a diet program. The mean weight fell to 84.5 ± 11.3 (P < 0.0001) and body mass index to 31.3 ± 4.9 (P < 0.0001). Plasma TNFα concentrations were markedly elevated in the obese (3.45 ± 0.16 pg/mL), when compared with controls (0.72 ± 0.28 pg/mL), and fell significantly (2.63 ± 1.40 pg/mL) after weight loss (P < 0.02). The magnitude of insulin release after glucose (75 g) challenge (area under the curve) also fell significantly (P < 0.01) after weight loss. The magnitude of weight loss and fall in TNFα were related to basal body weight (r = 0.57, P < 0.001) and basal TNFα (r = 0.55, P < 0.001) concentrations, respectively, but not to each other or to the glucose-induced insulin release (area under the curve). We conclude that obesity is associated with increased plasma TNFα concentrations, which fall with weight loss. Because circulating TNFα may mediate insulin resistance in the obese, a fall in TNFα concentrations may contribute to the restoration of insulin resistance after weight loss, Thus, TNFα may be an important circulating cytokine, which may provide a potentially reversible mechanism for mediating insulin resistance.
Albumin Synthesis and Bone Collagen Formation in Human Immunodeficiency Virus-Positive Subjects: Differential Effects of Growth Hormone Administration1
Authors: McNurlan Margaret A. , Garlick Peter J. , Frost Robert A. , DeCristofaro Kim A. , Lang Charles H. , Steigbigel Roy T. , Fuhrer Jack , Gelato Marie
Published: January 2014

Loss of lean tissue often accompanies human immunodeficiency virus (HIV) infection. Exogenous human recombinant GH (hrGH) has been shown to be beneficial in reversing this wasting. However, catabolic effects of hrGH on muscle protein metabolism have also been reported. Therefore, the responsiveness of other GH-sensitive tissues, including bone formation and albumin synthesis, has been examined.

Anabolic activity in bone, from serum levels of carboxy-terminal propeptide of type I collagen, was stimulated by 2 weeks of hrGH in controls (56 ± 15%, P = 0.002), patients with asymptomatic HIV (24 ± 10%, not significant), patients with AIDS (47 ± 7%, P < 0.001), and patients with AIDS and >10% weight loss (21 ± 12%, P = 0.02). Albumin synthesis, determined from the incorporation of L-[2H5]phenylalanine, was increased in response to hrGH in controls (23 ± 7%, P < 0.05), HIV+ subjects (39 ± 16%, P < 0.05), and patients with AIDS (25 ± 7%, P < 0.01). Patients with AIDS and weight loss, however, did not increase albumin synthesis (−0.6 ± 12%) in response to hrGH.

The results indicate variable anabolic responses to hrGH. Bone collagen synthesis remained sensitive to hrGH, whereas, the anabolic action of hrGH on the synthesis of albumin diminished with severity of disease. However unlike muscle protein synthesis, albumin synthesis was not depressed below basal levels by hrGH.
Diurnal Rhythms of Luteinizing Hormone, Follicle-Stimulating Hormone, and Testosterone Secretion before the Onset of Male Puberty1
Authors: Mitamura Ryo , Yano Koichi , Suzuki Naoki , Ito Yoshiya , Makita Yoshio , Okuno Akimasa
Published: January 2014

To investigate hormonal change before the onset of male puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone hourly for 24 h. Forty-six boys (32 prepubertal and 14 pubertal) of short stature, between 4.4–19.3 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone was measured using high sensitivity RIA capable of detecting a testosterone concentration of 0.01 ng/mL.

Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 4–5 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated at early morning in all subjects. Mean 24-h LH, FSH, and testosterone concentrations of prepubertal subjects who did not attain puberty for at least 3 yr were 0.10 U/L, 0.63 U/L, and 0.06 ng/mL, respectively, whereas those of prepubertal subjects who attained puberty within 1 yr (0.54 U/L, 1.68 U/L, and 0.10 ng/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, and testosterone concentrations increased with developing puberty. All of the 46 subjects showed positive cross-correlation between the LH and testosterone time series. The mean lag time from the LH to the testosterone time series in the prepubertal subjects who attained puberty within 1 yr (4.7 ± 2.4 h, mean ± sd) was shorter than that in the prepubertal subjects who attained puberty after at least 3 yr (7.3± 2.2 h). This lag time decreased with developing puberty, plateauing at 1.4 ± 0.9 h at midpuberty.

Thus, the diurnal rhythms of LH, FSH, and testosterone already exist at 4–5 yr of age; serum LH, FSH, and testosterone levels increase before the onset of puberty; and a time delay is observed between the LH and testosterone time series that decreases before the onset of puberty.
Low Dose Estrogen and Calcium Have an Additive Effect on Bone Resorption in Older Women1
Authors: Prestwood K. M. , Thompson D. L. , Kenny A. M. , Seibel M. J. , Pilbeam C. C. , Raisz L. G.
Published: January 2014

Previous studies have shown that treatment with estrogen or calcium decreases bone turnover in older women. The mechanisms by which estrogen and calcium exert their effects are probably different. We therefore examined the possibility of an additive or synergistic effect of combined treatment with calcium and low dose estrogen on bone turnover in older women, using biochemical markers.

Thirty-one healthy women over 70 yr of age were randomized to 12 weeks of treatment with either micronized 17β-estradiol [0.5 mg/day Estrace (E2)] or 1500 mg/day elemental calcium, given as carbonate plus vitamin D (800 IU/day; Ca+D). At the end of the initial 12-week treatment period, both groups received both Ca+D and E2 for an additional 12 weeks. Eleven older women were followed for 36 weeks without any treatment and served as a control group.

Serum and urine were collected at baseline, at 12 and 24 weeks on treatment, and at 12 weeks after treatment was terminated for measurement of biochemical markers of bone turnover. Markers of bone formation were bone alkaline phosphatase, osteocalcin, and type I procollagen peptide; markers of bone resorption were urinary cross-linked C-telopeptides and N-telopeptides of type I collagen, serum cross-linked N-telopeptides of type I collagen, urinary free deoxypyridinoline cross-links, and serum bone sialoprotein. Repeated measures ANOVA was used to determine changes in bone turnover measures over time by group.

All markers of bone resorption decreased with initial treatment and decreased further with combination therapy (P < 0.001). Markers of bone formation decreased with Ca+D treatment, but not with E2 alone; there was no additional effect of combination therapy on formation markers compared to Ca+D alone. Neither markers of formation nor resorption changed in the control group.

These results suggest that there is an additive effect of low dose estrogen and calcium on bone resorption, but not on bone formation, in older women. Thus, the combination of low dose estrogen plus calcium is likely to be more effective in older women than either treatment alone.
Joint Basal and Pulsatile Hypersecretory Mechanisms Drive the Monotropic Follicle-Stimulating Hormone (FSH) Elevation in Healthy Older Men: Concurrent Preservation of the Orderliness of the FSH Release Process: A General Clinical Research Center Study*
Authors: Veldhuis J. D. , Iranmanesh A. , Demers L. M. , Mulligan T.
Published: January 2014

To appraise the neuroendocrine mechanisms that underlie a selective (monotropic) elevation of serum FSH concentrations in healthy older men, we sampled blood in 11 young (ages 21–34) and 8 older men (ages 62–72) men every 2.5 min overnight. Serum FSH concentrations were quantitated in an automated, high-sensitivity, chemiluminescence-based assay. Rates of basal and pulsatile FSH secretion were estimated by deconvolution analysis, and the orderliness of the FSH release process via quantitated the approximate entropy statistic. Statistical analysis revealed that healthy older men manifest dual neuroendocrine hypersecretory mechanisims; specifically, a 2-fold increase in the basel (nonpulsatile) FSH secretion rate, and a concurrent 50% amplification of FSH secretory burst mass (and amplitude). The regularity or orderliness of ad seriatim FSH release is preserved in older individuals. We postulate that higher basel FSH secretion in older men is a consequence of reduced testosterone negative feedback, whereas amplified FSH secretory burst mass reflects net enhanced stimulation of gonadotrope cells by endogenous FSH secretagogues (e.g. GnRH and/or activin). The foregoing specific mechanisms driving heightened FSH secretion in older men contrast with the lower-amplitude pulsatility and more disorderly patterns of LH release in the same individuals. Thus, the present data illuminate an age-dependent disparity in the disruption of FSH neuroregulation in the aging male.
Leptin and Androgens in Male Obesity: Evidence for Leptin Contribution to Reduced Androgen Levels*
Authors: Isidori Andrea M. , Caprio Massimiliano , Strollo Felice , Moretti Costanzo , Frajese Gaetano , Isidori Aldo , Fabbri Andrea
Published: January 2014

Leptin circulates in plasma at concentrations that parallel the amount of fat reserves. In obese males, androgen levels decline in proportion to the degree of obesity. Recently, we have shown that in rodent Leydig cells leptin inhibits hCG-stimulated testosterone (T) production via a functional leptin receptor isoform; others have found that leptin inhibits basal and hCG-induced T secretion by testis from adult rats. In this study, we further investigated the relationship linking leptin and androgens in men. Basal and hCG-stimulated leptin and sex hormone levels were studied in a large group of men ranging from normal weight to very obese (body mass index, 21.8–55.7). Initial cross-sectional studies showed that circulating leptin and fat mass (FM) were inversely related with total and free T (r = −0.51 and r = −0.38, P < 0.01 and P < 0.05, respectively). Multiple regression analysis indicated that the correlation between leptin or FM and T was not lost after controlling for SHBG and/or LH and/or estradiol (E2) levels and that leptin was the best hormonal predictor of the lower androgen levels in obesity. Dynamic studies showed that in obese men the area under the curve of T and free T to LH/hCG stimulation (5000 IU im) was 30–40% lower than in controls and inversely correlated with leptin levels (r = −0.45 and r = −0.40, P < 0.01 and P < 0.05, respectively). Also, LH/hCG-stimulation caused higher increases in 17-OH-progesterone to T ratio in obese men than in controls, whereas no differences were observed between groups either in stimulated E2 levels or in the E2/T ratio. In all subjects, the percentage increases from baseline in the 17-OH-progesterone to T ratio were directly correlated with leptin levels or FM (r = 0.40 and r = 0.45, P < 0.01), but not with E2 or other hormonal variables. In conclusion, our studies, together with previous in vitro findings, indicate that excess of circulating leptin may be an important contributor to the development of reduced androgens in male obesity.
The Effect of Deydroepiandrosterone Supplementation to Symptomatic Perimenopausal Women on Serum Endocrine Profiles, Lipid Parameters, and Health-Related Quality of Life1
Authors: Barnhart Kurt T. , Freeman Ellen , Grisso Jeanne Anne , Rader Daniel J. , Sammel Mary , Kapoor Shiv , Nestler John E.
Published: January 2014

Dehydroepiandrosterone (DHEA), an androgenic steroid hormone, exhibits an age-related decline. Perimenopausal women have only approximately 50% of peak DHEA levels. Despite limited scientific data, DHEA has gained recognition as a dietary supplement to reduce the symptoms of aging and improve well-being. This randomized, double-blind placebo-controlled trial examined the effects of 50 mg/day of oral DHEA supplementation, for 3 months, on 60 perimenopausal women with complaints of altered mood and well-being.

Changes in the serum endocrine profile of women in the DHEA group were significantly greater than the placebo group, including a 242% [95% confidence interval (CI) +60.1, +423.9] increase in DHEAS, a 94.8% (95% CI +34.2, +155.4) increase in testosterone, and a 13.2% (95% CI− 27.88, +0.5) decline in cortisol compared to baseline. Women receiving DHEA had a 10.1% (95% CI −15.0, −5.1) decline in high-density lipoprotein and an 18.1% (95% CI −32.2, −3.9) decline in Lp(a) from baseline, but these declines did not significantly differ from women who received placebo. Women receiving DHEA did not have any improvements significantly greater than placebo in the severity of perimenopausal symptoms, mood, dysphoria, libido, cognition, memory, or well-being.

DHEA supplementation significantly effects the endocrine profile, may affect the lipid profile, but does not improve perimenopausal symptoms or well-being compared to placebo.
Prospectively Measured Levels of Serum Follicle-Stimulating Hormone, Estradiol, and the Dimeric Inhibins during the Menopausal Transition in a Population-Based Cohort of Women1
Authors: Burger Henry G. , Dudley Emma C. , Hopper John L. , Groome Nigel , Guthrie Janet R. , Green Adele , Dennerstein Lorraine
Published: January 2014

The aims of this study were: 1) to describe, in relation to the date of final menses, the average hormone levels of women in the years before and after this date and to determine the extent to which these average levels were dependent on age and body mass index (BMI); and 2) to determine the degree of tracking in residual hormone levels[ i.e., the extent to which individuals above (below) the mean for their age or time relative to final menstrual period (FMP) and BMI remain above (below) the mean as time progresses]. Serial levels of serum FSH, circulating estradiol (E2), and the dimeric inhibins (INH) A and B were measured annually in 150 women who experienced a natural menopause during 6 years of follow-up. Means of the log-transformed hormonal levels were analyzed as a double-logistic function of time relative to FMP, as well as age and BMI and correlations between repeated hormonal levels, were measured. Mean FSH levels started to increase from about 2 years before the FMP, increased most rapidly about 10 months before the FMP, and had virtually plateaued by 2 years after the FMP. FSH levels were, on average, 3% greater for each year of age and 2% lower for each kg/m2 of BMI. After adjusting for time relative to the FMP, logFSH showed modest tracking. Age-adjusted values of logFSH were moderately correlated across time, and much of this tracking was explained by the actual timing of a woman’s FMP. Mean E2 levels started to decrease about 2 years before the FMP, decreased most rapidly around the time of the FMP, and had virtually plateaued by 2 years after the FMP. E2 levels were lower, on average, by about 9% per year of age, and residual values showed weak tracking. Levels of both INHA and INHB decreased, on average, in the years before the FMP and were undetectable (INHA, <10 pg/mL; INHB, < 25 pg/mL) in the majority of women by the time of the FMP and in almost all women by 4 years post-FMP. Significant negative correlations between log serum FSH and log E2 (r = −0.73) and log INHA (r = −0.41) and log INHB (r = −0.36) were observed. It is concluded that substantial changes in reproductive hormone levels occur within 1–2 yr on each side of the FMP, that falling concentrations of E2 and the INH contribute to the rising concentrations of FSH, and that there is no single reliable hormonal marker of menopausal status for an individual woman.
Risk Factors and Long-Term Follow-Up of Adrenal Incidentalomas1
Authors: Barzon Luisa , Scaroni Carla , Sonino Nicoletta , Fallo Francesco , Paoletta Agostino , Boscaro Marco
Published: January 2014

The natural course of adrenal incidentalomas and the risk that such lesions evolve toward hormonal hypersecretion or malignancy are still under evaluation. Of 246 consecutive patients with adrenal incidentaloma studied at our institution in the last 15 yr, 91 underwent surgery. Of the remaining patients, a group of 75 (52 females and 23 males; median age, 56 yr; range, 19–77 yr) with incidentally discovered asymptomatic adrenal masses (60 unilateral and 15 bilateral; median diameter, 2.5 cm; range, 1.0–5.6) was enrolled in an endocrine and morphological follow-up of at least 2 yr after diagnosis (median, 4 yr; range, 2–10). During follow-up, no patients developed malignancy; 9 showed mass enlargement, with appearance of a new mass in the contralateral gland in 2; 3 developed adrenal hyperfunction (overt Cushing’s syndrome in 2, nonclinical hypercortisolism in 1); and 3 showed adrenal mass enlargement associated with adrenal hyperfunction (nonclinical hypercortisolism in 2, pheochromocytoma in 1). The estimated cumulative risks to develop mass enlargement and hyperfunction were 8% and 4%, respectively, after 1 yr, 18% and 9.5% after 5 yr, and 22.8% and 9.5% after 10 yr. Nine risk factors for adrenal mass enlargement or hyperfunction were arbitrarily selected and evaluated: sex, age, presence of obesity, hypertension, diabetes, abnormal endocrine tests, mass size, mass location, and scintigraphic uptake pattern. Three of them attained statistical significance: mass size of 3 cm or more at diagnosis and exclusive radiocholesterol uptake by the mass at scintigraphy had relevance for the occurrence of adrenal hyperfunction, whereas the presence of endocrine test abnormalities at diagnosis had predictive value for mass enlargement. It is concluded that subtle hormonal abnormalities are risk factors for mass size increase, which is not a sign of malignant transformation. Both mass size of 3 cm or more at diagnosis and exclusive radiocholesterol uptake, indicating higher risks of hyperfunction, should be considered to plan a more thorough endocrine follow-up.
Brain Natriuretic Peptide and Neutral Endopeptidase Inhibition in Left Ventricular Impairment1
Authors: Lainchbury John G. , Richards A. Mark , Nicholls M. Gary , Espiner Eric A. , Yandle Timothy G.
Published: January 2014

Brain natriuretic peptide (BNP) is increased in left ventricular impairment and neutral endopeptidase (NEP) is involved in its metabolism. In random order, eight patients with left ventricular impairment received placebo, a 4-h infusion of human BNP (3.0 pmol/kg min), a single oral dose of NEP inhibitor (SCH 42495, 300 mg), and combined BNP and SCH 42495. Plasma BNP, cGMP, and cortisol were significantly increased by all three treatments (P < 0.05–P < 0.001). Combined treatment had a synergistic effect on plasma cGMP. The metabolic clearance rate of exogenous BNP was reduced (25%) by NEP inhibition. Endogenous plasma ANP was augmented more than BNP by NEP inhibition. Plasma aldosterone, unchanged during infusions, rose markedly after BNP and after the combined treatment (P < 0.05 for both). Urine sodium excretion, increased by NEP inhibition (P < 0.05) and by BNP (P = 0.05), was unchanged during combined treatment. Urine cGMP excretion was increased, whereas blood pressure was reduced by all active treatments (P < 0.05–0.01 for all). Heart rate increased only with combined treatment (P = 0.007). Plasma renin activity, norepinephrine, and cardiac output were unaffected.

BNP infusion and NEP inhibition both induced significant hemodynamic and renal responses. The augmented hypotensive effect of combined treatments, and consequent fall in renal perfusion pressure, may underly the observed blunting of the natriuretic response that occurred despite greater than additive increments in plasma BNP, ANP, and cGMP.
Free α-Subunit Is Superior to Luteinizing Hormone as a Marker of Gonadotropin-Releasing Hormone Despite Desensitization at Fast Pulse Frequencies1
Authors: Hayes Frances J. , McNicholl Dennis J. , Schoenfeld David , Marsh Erica E. , Hall Janet E.
Published: January 2014

A pulsatile pattern of GnRH stimulation is essential for normal secretion of luteinizing hormone (LH), while both continuous and fast-frequency GnRH stimulation result in a paradoxical decrease in gonadotrope responsiveness known as desensitization. Under physiological conditions there is striking concordance between the pulsatile secretion of LH and the glycoprotein free α-subunit (FAS). The aims of this study were to determine whether the FAS response to GnRH is also decreased at fast frequencies of GnRH stimulation and whether FAS is superior to LH as a marker of GnRH secretory activity at fast-pulse frequencies. The model of GnRH-deficient men was chosen to permit precise control of the dose and frequency of GnRH stimulation of the gonadotrope. The frequency of iv administration of GnRH to 5 GnRH-deficient men was progressively increased from every 120 to every 60 min, from 60 to 30 min, and from 30 to 15 min during three 12-h admissions, 1 week apart. The bolus dose of GnRH remained constant and was set at that dose previously shown to produce physiological concentrations and amplitudes of LH secretion and normal testosterone levels.

As the frequency of GnRH stimulation was increased, a progressive rise in mean FAS levels was noted (353 ± 13, 448 ± 42, 466± 50, and 698 ± 85 ng/L [mean ± sem] for 120, 60, 30, and 15 min intervals; P < 0.005). However, normalization of mean FAS levels to account for the increase in total GnRH delivered with increasing frequencies revealed a progressive decrease in pituitary responsiveness to each GnRH bolus with increasing frequency of stimulation (353 ± 13, 224 ± 21, 117 ± 13, 87 ± 11 ng/L; P < 0.001). The decrease in normalized mean levels was supported by a decrease in the FAS pulse amplitude with increasing frequency (517± 53, 365 ± 50, 176 ± 29 ng/L for 120, 60, and 30 min intervals, respectively; P < 0.005).

At interpulse intervals of 120 and 60 min, there was complete concordance of LH and FAS pulses in response to GnRH. However, at the 30-min frequency FAS proved to be a better marker of GnRH with a higher true positive rate and lower number of false positives than LH (P < 0.05). At all frequencies, the number of false positive pulses detected tended to be lower for FAS than for LH (P = 0.06).

From these data we conclude that FAS is subject to desensitization in response to increasing frequencies of GnRH administration in GnRH-deficient men, but is superior to LH as a surrogate marker of GnRH pulse generator activity at fast pulse frequencies.