Home About us Contact
|
Home About us Contact | ||
|
|
||
Hormone Production (hormone + production)
Selected AbstractsElevated organochlorines in the brain,hypothalamic,pituitary complex of intersexual shovelnose sturgeonENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006Brian T. Koch Abstract Organochlorine compounds (OCs), including polychlorinated biphenyls and organochlorine pesticides, were used on lands adjacent to the Middle Mississippi River (MMR; USA) from 1930 through 1988, and they continue to occur in MMR fish. These compounds are estrogenic and/or antiandrogenic, and they alter hormone production and reception within the brain and gonads of male fish, resulting in intersexuality and/or suppressed gonadal development. To assess how OCs affect reproduction of MMR fish, we quantified OC accumulation, intersexuality, and gonadal development in male shovelnose sturgeon (Scaphirhynchus platorynchus) throughout the MMR during the spring of 2003. Gonads were observed for intersexual characteristics, weighed to calculate the gonadosomatic index (GSI), and examined histologically. Tissue accumulation of OCs was quantified in gonads, brain,hypothalamic,pituitary (BHP) complex, and fillets. Four of 48 mature males were identified macroscopically as intersexuals, and a fifth was found through histology (a 10.4% incidence). Intersexuals accumulated higher concentrations of OCs in the BHP complex compared with those of mature males. In addition, GSI and OC accumulation within the BHP complex, gonads, and fillets of mature males were negatively related. Exposure to OCs before or during sexual differentiation likely induces intersexuality in MMR shovelnose sturgeon, and exposure throughout gonadal maturation inhibits gonadal development. [source] Mitochondrial function and endocrine diseasesEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2007R. Stark Abstract Mitochondria are fundamental for oxidative energy production and impairment of their functionality can lead to reduced ATP synthesis and contribute to initiation of apoptosis. Endocrine tissues critically rely on oxidative phosphorylation so that mitochondrial abnormalities may either be causes or consequences of diminished hormone production or action. Abnormalities typical for diseases caused by mitochondrial DNA mutations such as Kearns,Sayre syndrome or mitochondrial encephalomyopathy, lactic acidosis, and stroke,like episodes syndrome are also seen in certain endocrine diseases. Lack or excess of thyroid hormones, major ubiquitous regulators of mitochondrial content and activity, cause muscular abnormalities and multisystem disorders. Mitochondria are a further prerequisite for steroidogenesis as well as insulin secretion and action. Recent studies showed that reduced mitochondrial ATP synthesis in skeletal muscle is a feature of certain hereditary and acquired forms of insulin resistance and diabetes mellitus. Finally, ageing is not only accompanied by various degrees of hormonal deficiency and insulin resistance but is also associated with a progressive decline of mitochondrial number and function. Future research is needed to examine whether mitochondrial abnormalities are the cause or consequence of ageing and frequent metabolic diseases such as obesity and type 2 diabetes mellitus, and to address mitochondria as a target for novel therapeutic regimes. [source] Thyroid hormones determine developmental mode in sand dollars (Echinodermata: Echinoidea)EVOLUTION AND DEVELOPMENT, Issue 6 2004Andreas Heyland Summary Evolutionary transitions in larval nutritional mode have occurred on numerous occasions independently in many marine invertebrate phyla. Although the evolutionary transition from feeding to nonfeeding development has received considerable attention through both experimental and theoretical studies, mechanisms underlying the change in life history remain poorly understood. Facultative feeding larvae (larvae that can feed but will complete metamorphosis without food) presumably represent an intermediate developmental mode between obligate feeding and nonfeeding. Here we show that an obligatorily feeding larva can be transformed into a facultative feeding larva when exposed to the thyroid hormone thyroxine. We report that larvae of the subtropical sand dollar Leodia sexiesperforata (Echinodermata: Echinoidea) completed metamorphosis without exogenous food when treated with thyroxine, whereas the starved controls (no thyroxine added) did not. Leodia sexiesperforata juveniles from the thyroxine treatment were viable after metamorphosis but were significantly smaller and contained less energy than sibling juveniles reared with exogenous food. In a second starvation experiment, using an L. sexiesperforata female whose eggs were substantially larger than in the first experiment (202±5 vs. 187±5 ,m), a small percentage of starved L. sexiesperforata larvae completed metamorphosis in the absence of food. Still, thyroxine-treated larvae in this experiment completed metamorphosis faster and in much higher numbers than in the starved controls. Furthermore, starved larvae of the sand dollar Mellita tenuis, which developed from much smaller eggs (100±2 ,m), did not complete metamorphosis either with or without excess thyroxine. Based on these data, and from recent experiments with other echinoids, we hypothesize that thyroxine plays a major role in echinoderm metamorphosis and the evolution of life history transitions in this group. We discuss our results in the context of current life history models for marine invertebrates, emphasizing the role of egg size, juvenile size, and endogenous hormone production for the evolution of nonfeeding larval development. [source] Primary and secondary small cell neuroendocrine carcinoma of the larynx: A reviewHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 4 2008Alfio Ferlito MD, DPath, FASCP, FDSRCS, FHKCORL, FRCPath, FRCSEd, FRCSGlasg, FRCSI Abstract Primary laryngeal small cell neuroendocrine carcinoma (SCNC) is an unusual malignancy accounting for <0.5% of laryngeal carcinomas. To date, approximately 200 cases of primary and 5 of secondary SCNC of the larynx have been reported. This tumor most often presents in the sixth and seventh decades in men who are heavy cigarette smokers. The lesion may be associated with different paraneoplastic syndromes (ectopic adrenocorticotropic hormone syndrome, Schwartz,Bartter syndrome or syndrome of inappropriate secretion of antidiuretic hormone, and Eaton,Lambert myasthenic syndrome) or with ectopic hormone production. The diagnosis is based essentially on the histologic appearance of the tumor, confirmed by immunocytochemical investigations. Concurrent chemoradiotherapy regimens offer potential for long-term survival. This tumor is biologically aggressive, and the extent of the disease is the most significant independent prognostic factor of survival. The survival rate is similar to that with pulmonary SCNC. © 2008 Wiley Periodicals, Inc. Head Neck, 2008 [source] Steroidogenic gene expression in H295R cells and the human adrenal gland: adrenotoxic effects of lindane in vitroJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2006Agneta Oskarsson Abstract The focus on the refinement, reduction and replacement of animal use in toxicity testing requires the development of cell-based systems that mimic the effects of xenobiotics in human tissues. The human adrenocortical carcinoma cell line, H295R, has been proposed as a model for studies on adrenal steroidogenesis and its disruption. In this study, expression profiles for nine adrenal steroidogenic genes were characterized in H295R cells using real-time RT-PCR. Treatment with forskolin increased cortisol secretion and stimulated transcription of all the steroidogenic genes except SULT2A1. The transcript profile from H295R cells in the presence and absence of forskolin was compared with the transcript profile from human adrenal glands. The gene expression pattern observed in the forskolin-treated H295R cells was more similar to that in the human adrenal gland, than the expression pattern in untreated cells. To examine H295R cells as a possible in vitro system for the assessment of adrenal disruption using molecular endpoints, the insecticide lindane (, -hexachlorocyclohexane) was used. In vivo, lindane has been shown to inhibit testicular, ovarian and adrenal steroidogenesis. It was demonstrated that lindane reduced cortisol secretion, downregulated the expression of a subset of the genes encoding steroidogenic enzymes and repressed transcriptional activation of the steroidogenic acute regulatory protein (StAR) gene promoter. Thus the H295R cell line provides a good in vitro system for the analysis of the human adrenal steroidogenic pathway at the level of hormone production and gene expression. This in vitro test can be used for the rapid detection of adrenal endocrine disruption and as a tool for mechanistic studies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Atypical attack of acute intermittent porphyria , paresis but no abdominal painJOURNAL OF INTERNAL MEDICINE, Issue 3 2002C. Andersson Abstract.,Andersson C, Nilsson A, Bäckström T (University Hospital, Umeå, Sweden; and Primary Health Care Centre, Arvidsjaur). Atypical attack of acute intermittent porphyria , paresis but no abdominal pain (Case report). J Intern Med 2002; 252: 265,270. We report a case of acute intermittent porphyria (AIP) in a 45-year-old woman. Her first attack occurred at the age of 38. Because of escalating cyclical premenstrual attacks, the following 2 years, depletion of the endogenous sex hormone was considered as haeme arginate treatment proved insufficient. Gonadotropin releasing hormone agonist treatment with low-dose oestradiol add back was quite successful initially but was abandoned after 18 months when progesterone add back precipitated a severe attack. Following hysterectomy and oophorectomy at age 42 and oestradiol add back, a remarkable monthly regularity of attacks ensured periodically but with milder symptoms. Two years after surgery, preceded by six attack-free months, a puzzling symptom-shift occurred, from abdominal pain, back and thigh pain during the attacks, to solely severe distal extensor paresis in the arms. Haeme arginate treatment interrupted the progress of the paresis almost immediately and motor function improved considerably up to the 9-month follow-up. Electrophysiological examination revealed only motor neuropathy, consistent with axonal degeneration. Subsequently the symptoms changed yet again, to sensory disturbances with numbness and dysesthesia as the primary expression followed by rather mild abdominal pain. However, cyclical attacks occurred, despite absence of endogenous ovarial hormone production, possibly attributable to impaired oestrogen metabolism in the liver, or adrenal oestrogen production. Treatment comprising oophorectomy, low-dose oestradiol add back and haeme arginate infusion for 2 days on the appearance of early AIP symptoms is now quite successful affording improvement in life quality. [source] White Adipose Tissue: Getting NervousJOURNAL OF NEUROENDOCRINOLOGY, Issue 11 2003E. Fliers Abstract Neuroendocrine research has altered the traditional perspective of white adipose tissue (WAT) as a passive store of triglycerides. In addition to fatty acids, WAT produces many hormones and can therefore be designated as a traditional endocrine gland actively participating in the integrative physiology of fuel and energy metabolism, eating behaviour and the regulation of hormone secretion and sensitivity. WAT is controlled by humoral factors, para- and intracrine factors and by neural regulation. Sympathetic nerve fibres innervate WAT and stimulate lipolysis, leading to the release of glycerol and free fatty acids. In addition, recent research in rats has clearly shown a functional parasympathetic innervation of WAT. There appears to be a distinct somatotopy within the parasympathetic nuclei: separate sets of autonomic neurones in the brain stem innervate either the visceral or the subcutaneous fat compartment. We therefore propose that the central nervous system (CNS) plays a major role in the hitherto unexplained regulation of body fat distribution. Parasympathectomy induces insulin resistance with respect to glucose and fatty acid uptake in the innervated fat depot and has selective effects on local hormone synthesis. Thus, the CNS is involved not only in the regulation of hormone production by WAT, but also in its hormone sensitivity. The developments in this research area are likely to increase our insights in the pathogenesis of metabolic disorders such as hypertriglyceridemia, diabetes mellitus type 2 and lipodystrophy syndromes. [source] Effects of FSH and LH on Steroid Production by Buffalo (Bubalus bubalis) Granulosa Cells Cultured In Vitro Under Serum-Free ConditionsREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2010M Shanmugam Contents The objective of this study was to examine the effects of FSH and LH on oestradiol-17, and progesterone production by buffalo granulosa cells cultured under serum-free conditions. Granulosa cells (3 × 105) from small (,5 mm diameter) follicles were cultured for up to 4 days in 48-well plates coated with 3.3 ,g/cm2 fibronectin in Dulbecco's modified Eagle's medium (DMEM) : nutrient mixture F-12 Ham (1 : 1 ratio) supplemented with 10,7 m androstenedione, 5 ,g/ml human apo-transferrin and 0.1% bovine serum albumin, in the presence or absence of FSH or LH (0, 1, 2, 4, 8, 16, 32 or 64 ng/ml each). Basal oestradiol-17, production by granulosa cells from small follicles reduced (p < 0.01) from days 1 to 2 of culture and became undetectable by day 3 and basal progesterone production increased (p < 0.05) from day 1 through day 4 of the culture. Although there was no effect of FSH on day 1 of the culture, FSH at 2, 4, 8 and 16 ng/ml increased (p < 0.05) oestradiol-17, production by granulosa cells from small follicles on day 2. Progesterone secretion was increased (p < 0.05) by all doses of FSH on all days of culture. All doses of LH had no effect on oestradiol-17, or progesterone production by granulosa cells from small follicles on any day of the culture. The results of this study demonstrate a serum-free culture system for buffalo granulosa cells and stimulatory effect of FSH but not LH on steroid hormone production by buffalo granulosa cells under these conditions. [source] Moderate Seasonality in Testis Function of Domestic CatREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2007S Blottner Contents Adult male domestic cats are known to produce sperm throughout the year, although sexual activity is influenced by geographical location. In the northern hemisphere, feral domestic cats reproduce usually between January and July. Thus, seasonality in testicular activity might be suggested. The aim of the present study was to investigate gametogene and endocrine activity of cat testis throughout the entire year. Testes and epididymides (n = 10,12 per month) were collected after castration. Spermatogenesis was quantified by assessment of testicular sperm per testis and by flow cytometric analysis of the cells with different DNA content. Sperm from cauda epididymis were evaluated according to motility and morphological integrity. Testicular testosterone concentration was determined by enzyme immunoassay. Testis mass and sperm production varied moderately throughout the year. Significant seasonal variations were observed in the proportion of cells in the G2/M phase of cell cycle (p = 0.004) and the meiotic transformation (ratio of haploid : tetraploid cells; p = 0.021). Changes in testicular testosterone concentration were more pronounced and showed periods with high (spring) and significantly reduced testosterone levels (autumn). A marked seasonal alteration (p < 0.001) with a peak in March was assessed in the percentage of progressively motile sperm. The proportion of morphological intact sperm was also significantly higher in spring compared with winter time (p < 0.001). In conclusion, the study suggests moderate seasonal changes in quantity of sperm, more pronounced annual variation in hormone production and a distinct seasonal influence on functional sperm parameters in domestic cat. [source] Initiation of Steroidogenesis Precedes Expression of Cholesterologenic Enzymes in the Fetal Mouse TestesANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009T. Büdefeld Summary Sexual differentiation is a carefully regulated process that ultimately results in a development of the male or female phenotype. Proper development of the male phenotype is dependent upon the action of testosterone and anti-mullerian hormone. Leydig cells start to produce testosterone around day 12.5 in the fetal mouse testis, and continue to produce high levels of this hormone throughout gestation. In the present study, we examined whether expression of lanosterol 14,-demethylase (cyp51) and cytochrome P450 NADPH reductase, both involved in the cholesterol production, occurs simultaneously with proteins required for the production of steroid hormones. Immunocytochemical staining with the antibodies against cyp51, cytochrome P450 NADPH reductase, steroidogenic acute regulatory protein (StAR) and 3beta-hydroxysteroid dehydrogenase I (3,-HSD I) was used to determine the ontogeny of expression of these four proteins. As expected, 3,-HSD I and StAR proteins were detected on day 12.5 p.c., while expression of cyp51 and NADPH cytochrome P450 reductase appeared 1 day later, on day 13.5. Thereafter, the expression of all four proteins remained strong throughout gestation. Results of this study suggest that initial steps of steroid hormone production in murine Leydig cells are mostly dependent on exogenously derived cholesterol, while from day 13.5 onwards, mouse Leydig cells are able to synthesize cholesterol and are therefore not dependent on exogenous cholesterol resources. [source] Expression system for recombinant human growth hormone production from Bacillus subtilisBIOTECHNOLOGY PROGRESS, Issue 1 2009Tunçer H. Özdamar Abstract We demonstrate for the first time, an expression system mimicking serine alkaline protease synthesis and secretion, producing native form of human growth hormone (hGH) from Bacillus subtilis. A hybrid-gene of two DNA fragments, i.e., signal (pre- ) DNA sequence of B. licheniformis serine alkaline protease gene (subC) and cDNA encoding hGH, were cloned into pMK4 and expressed under deg -promoter in B. subtilis. Recombinant-hGH (rhGH) produced by B. subtilis carrying pMK4::pre(subC)::hGH was secreted. N-terminal sequence and mass spectrometry analyses of rhGH confirm the mature hGH sequence, and indicate that the signal peptide was properly processed by B. subtilis signal-peptidase. The highest rhGH concentration was obtained at t = 32 h as CrhGH = 70 mg L,1 with a product yield on substrate YrhGH/S = 9 g kg,1, in a glucose based defined medium. Fermentation characteristics and influence of hGH gene on the rhGH production were investigated by comparing B. subtilis carrying pMK4::pre(subC)::hGH with that of carrying merely pMK4. Excreted organic-acid concentrations were higher by B. subtilis carrying pMK4::pre(subC)::hGH, whereas excreted amino-acid concentrations were higher by B. subtilis carrying pMK4. The approach developed is expected to be applicable to the design of expression systems for heterologous protein production from Bacillus species. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Inappropriate antidiuretic hormone production by leukaemic blasts in acute myeloid leukaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2009Kichinosuke Kobayashi No abstract is available for this article. [source] Differential effects of antiepileptic drugs on steroidogenesis in a human in vitro cell modelACTA NEUROLOGICA SCANDINAVICA, Issue 2009M. W. Gustavsen Objectives, To better understand the interaction of antiepileptic drugs and production of sex hormones, possible effects of valproate (VPA), levetiracetam (LEV) and carbamazepine (CBZ) on steroidogenesis were investigated in the human adrenal carcinoma cell line H295R. Materials and methods, H295R cells were exposed to different concentrations of VPA, LEV or CBZ for 48 h. Sex hormone concentrations and mRNA expression levels were analyzed via radioimmunoassay and quantitative real time (RT)-PCR, respectively. Results, In VPA-exposed cells estradiol levels decreased in a dose-dependent manner, while testosterone and progesterone levels were unaffected. Expression of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), steroidogenic acute regulatory protein (StAR), CYP11a, CYP17, CYP21, 3,HSD2, 17,HSD1 was downregulated and expression of CYP11,2 was upregulated. No effect on sex hormone production was observed under influence of LEV or CBZ. Expression of StAR, CYP17, CYP19 and 3,HSD2 was downregulated in LEV-exposed cells, and expression of HMGR, CYP11,2 and CYP17 was downregulated in CBZ-exposed cells. Conclusions, VPA exposure resulted in a decrease in estradiol levels and a general downregulation of expression of genes encoding for enzymes early in steroidogenesis. No consistent changes were seen with LEV or CBZ exposure. [source] | |||||||||||||