Pituitary Content Research Articles

Ghrelin Gene Deletion Alters Pulsatile Growth Hormone Secretion in Adult Female Mice.

Using preproghrelin-deficient mice (Ghrl-/-), we previously observed that preproghrelin modulates pulsatile growth hormone (GH) secretion in post-pubertal male mice. However, the role of ghrelin and its derived peptides in the regulation of growth parameters or feeding in females is unknown. We measured pulsatile GH secretion, growth, metabolic parameters and feeding behavior in adult Ghrl-/- and Ghrl+/+ male and female mice. We also assessed GH release from pituitary explants and hypothalamic growth hormone-releasing hormone (GHRH) expression and immunoreactivity. Body weight and body fat mass, linear growth, spontaneous food intake and food intake following a 48-h fast, GH pituitary contents and GH release from pituitary explants ex vivo, fasting glucose and glucose tolerance were not different among adult Ghrl-/- and Ghrl+/+ male or female mice. In vivo, pulsatile GH secretion was decreased, while approximate entropy, that quantified orderliness of secretion, was increased in adult Ghrl-/- females only, defining more irregular GH pattern. The number of neurons immunoreactive for GHRH visualized in the hypothalamic arcuate nucleus was increased in adult Ghrl-/- females, as compared to Ghrl+/+ females, whereas the expression of GHRH was not different amongst groups. Thus, these results point to sex-specific effects of preproghrelin gene deletion on pulsatile GH secretion, but not feeding, growth or metabolic parameters, in adult mice.

Effect of Growth Hormone Secretagogue Receptor Deletion on Growth, Pulsatile Growth Hormone Secretion, and Meal Pattern in Male and Female Mice

Introduction: While the vast majority of research investigating the role of ghrelin or its receptor, GHS-R1a, in growth, feeding, and metabolism has been conducted in male rodents, very little is known about sex differences in this system. Furthermore, the role of GHS-R1a signaling in the control of pulsatile GH secretion and its link with growth or metabolic parameters has never been characterized. Methods: We assessed the sex-specific contribution of GHS-R1a signaling in the activity of the GH/IGF-1 axis, metabolic parameters, and feeding behavior in adolescent (5–6 weeks old) or adult (10–19 weeks old) GHS-R KO (Ghsr−/−) and WT (Ghsr+/+) male and female mice. Results: Adult Ghsr−/− male and female mice displayed deficits in weight and linear growth that were correlated with reduced GH pituitary contents in males only. GHS-R1a deletion was associated with reduced meal frequency and increased meal intervals, as well as reduced hypothalamic GHRH and NPY mRNA in males, not females. In adult, GH release from Ghsr−/− mice pituitary explants ex vivo was reduced independently of the sex. However, in vivo pulsatile GH secretion decreased in adult but not adolescent Ghsr−/− females, while in males, GHS-R1a deletion was associated with reduction in pulsatile GH secretion during adolescence exclusively. In males, linear growth did not correlate with pulsatile GH secretion, but rather with ApEn, a measure that reflects irregularity of the rhythmic secretion. Fat mass, plasma leptin concentrations, or ambulatory activity did not predict differences in GH secretion. Discussion/Conclusion: These results point to a sex-dependent dimorphic effect of GHS-R1a signaling to modulate pulsatile GH secretion and meal pattern in mice with different compensatory mechanisms occurring in the hypothalamus of adult males and females after GHS-R1a deletion. Altogether, we show that GHS-R1a signaling plays a more critical role in the regulation of pulsatile GH secretion during adolescence in males and adulthood in females.

High hydrostatic pressure effects on arginine vasotocin levels in fish

The present study investigates the response of the hormone arginine vasotocin (AVT), the non-mammalian antidiuretic hormone, to the acclimation of fish to high hydrostatic pressure (5.1 MPa). Two fish species with different osmoregulatory strategies, the lesser spotted dogfish Scyliorhinus canicula, a marine osmoconforming chondrichthyan species adapted for migration to deep waters, and the rainbow trout Oncorhynchus mykiss, a pressure-sensitive freshwater species, were selected for study. Fish were exposed to hydrostatic pressures of either 0.1 (control) or 5.1 MPa in hydrostatic chambers for up to 2 wk at their appropriate salinities. Plasma cortisol was measured in trout, and plasma chloride, sodium and potassium were measured in both fish species. A transient high level of plasma AVT was found in dogfish and in trout after 1 and 3 d of exposure to high hydrostatic pressure, which returned to basal levels by 14 d of exposure. In contrast, pituitary AVT content was reduced after short-term exposure in dogfish, while in trout, lower expression was found in high pressure than in control conditions, independently of exposure time. In dogfish, pituitary AVT levels recovered by 14 d under high hydrostatic pressure. No changes in plasma cortisol (trout) or ions (both species) were observed. These initial increases of the AVT release from the pituitary during fish acclimation to high pressure suggest that it works as a physiological short-term response to reduce water loss and equilibrate ion osmotic balance.

Síndrome da sela vazia com herniação de giros retos

Introdução: Embora o conhecimento acerca da Síndrome da Sela Vazia seja bem vasto e documentado na literatura, existem poucos trabalhos esclarecendo os procedimentos aplicados em casos relatados, as dificuldades diagnósticas e de técnicas da intervenção, além dos resultados obtidos. Objetivo: Relatar o caso de um paciente jovem portador da Síndrome da Sela Vazia com herniação de giros retos, através da revisão retrospectiva do prontuário físico, abordando aspectos clínicos e cirúrgicos. Método: Foi realizado uma revisão retrospectiva do prontuário físico do paciente. Relato de caso: Paciente, 17 anos, apresentou-se inicialmente com sintomas de origem endócrina característicos de hipocortisolismo e hipogonadismo. Através do exame de imagem foi notada a presença de sela túrcica sem o habitual conteúdo hipofisário, mas com a presença de herniação de giros retos. Foi indicado tratamento cirúrgico e, com isso, houve melhora significativa no quadro de hipotensão, sendo necessário associar ao tratamento terapia de reposição hormonal. Discussão: A Síndrome da Sela Vazia (SSV) é caracterizada pela herniação da membrana aracnóide para dentro da sela túrcica, que pode atuar com efeito de massa, levando a falência da função pituitária O quadro clínico dependerá do fator etiológico, sendo necessário geralmente reposição hormonal para esses pacientes e em alguns casos a intervenção cirúrgica. Conclusão: A SSV é uma patologia importante que deve estar sempre entre os diagnósticos diferenciais em pacientes com clínica de hipogonadismo.

Glyphosate-based herbicide exposure during pregnancy and lactation malprograms the male reproductive morphofunction in F1 offspring.

One of the most consumed pesticides in the world is glyphosate, the active ingredient in the herbicide ROUNDUP®. Studies demonstrate that glyphosate can act as an endocrine disruptor and that exposure to this substance at critical periods in the developmental period may program the fetus to induce reproductive damage in adulthood. Our hypothesis is that maternal exposure to glyphosate during pregnancy and lactation in mice will affect the development of male reproductive organs, impairing male fertility during adult life. Female mice consumed 0.5% glyphosate-ROUNDUP® in their drinking water [glyphosate-based herbicide (GBH) group] or filtered water [control (CTRL) group] from the fourth day of pregnancy until the end of the lactation period. Male F1 offspring were designated, according to their mother's treatment, as CTRL-F1 and GBH-F1. Female mice that drank glyphosate displayed reduced body weight (BW) gain during gestation, but no alterations in litter size. Although GBH male F1 offspring did not exhibit modifications in BW, they demonstrated delayed testicular descent. Furthermore, at PND150, GBH-F1 mice presented a lower number of spermatozoa in the cauda epididymis and reduced epithelial height of the seminiferous epithelium. Notably, intratesticular testosterone concentrations were enhanced in GBH-F1 mice; we show that it is an effect associated with increased plasma and pituitary concentrations of luteinizing hormone. Therefore, data indicate that maternal exposure to glyphosate-ROUNDUP® during pregnancy and lactation may lead to decreased spermatogenesis and disruptions in hypothalamus-pituitary-testicular axis regulation in F1 offspring.

OR24-3 Persistence of Progenitor Cell Markers Following the Selective Ablation of Musashi in Somatotropes

Metabolic and reproductive demands are met and coordinated through the complex control of hormone synthesis and secretion exerted by the anterior pituitary. While pituitary cells are known to possess remarkable plasticity to change their cell fate and alter hormone production in response to ever changing environmental cues, the underlying molecular control of this plasticity has not been established. Our lab has previously introduced the Musashi (MSI) family of RNA binding proteins as important players in control of pituitary hormone levels. Musashi typically governs stem cell fate and promotes self-renewal by repressing translation of target mRNAs needed for differentiation. However, we found that MSI1 is expressed in most differentiated cells of the adult pituitary and can specifically bind to the 3’ UTRs of Prl, Tsh, and Pou1f1 and exert translational control in reporter assays. Confirmation of the requirement for MSI was demonstrated through in vivo analyses where MSI1 and MSI2 were selectively ablated in somatotropes. The mutant animals were subfertile. The mutant males showed reduced serum and pituitary content of LH and FSH, and significant decreases in serum GH and PRL despite 2-fold increases in pituitary protein content of PRL and GH. To further assess the role and downstream pathways regulated by MSI in the pituitary, we collected somatotrope MSI-null pituitaries from males and females for qPCR analysis of common somatotrope target genes. In correlation with our previous findings described above (low serum GH and high pituitary GH content), we found that GHRHR mRNA levels were reduced by 2-fold in male mutants. RNA-seq analysis followed by qPCR validation shows that Prop1 mRNA was significantly increased in male mutants, with no significant change in Pou1f1 mRNA. These data suggest that MSI may be involved in the regulation of progenitor cells giving rise to the somatotrope lineage and that MSI ablation may have caused retention of these progenitors and/or a failure to fully differentiate somatotropes. Our studies of MSI-null somatotrope function support this interpretation because the mutant somatotropes clearly stored GH proteins, but could not secrete them, as demonstrated by the low serum GH values, and the 50% reduction in GHRHR mRNA. RNA-seq evaluation of males revealed a change in the expression of 720 genes between controls and mutants (FDR <0.05). When we examined female MSI-null somatotrope animals, a much smaller cohort of genes showed a change in expression (153 genes, FDR <0.05). Interestingly, 38 genes were altered in both mutant males and females suggesting shared regulation by MSI. Further characterization of the NGS datasets will elucidate additional downstream targets and effector pathways of MSI-dependent control of anterior pituitary cell differentiation and function.

Endocrine and reproductive responses of male and female cattle to agonists of gonadotrophin-releasing hormone

The pituitary response in cattle to treatment with GnRH agonist has two phases. In the acute phase secretion of LH is increased, while the chronic phase is characterized by a downregulation of GnRH receptors and insensitivity of gonadotrophs to natural sequence GnRH. After long-term treatment with GnRH agonist, cattle do not have pulsatile secretion of LH but maintain basal LH. This is associated with reduced pituitary contents of LH, LH mRNA, FSH and FSH mRNA. Long-term treatment of bulls with GnRH agonist results in an increase in testicular LH receptors and high plasma testosterone. Heifers treated with a GnRH agonist from early in the oestrous cycle develop a larger corpus luteum and secrete more progesterone. Increased steroidogenesis is reflected in increased steroid acute regulatory (StAR) protein and steroidogenic enzymes in the testes and corpus luteum. GnRH agonists have potential as novel strategies for reproductive management in cattle. A GnRH agonist bioimplant was recently used to block the LH surge after FSH stimulation of follicle growth in heifers. Ovulation was induced by injection of LH, and heifers were inseminated relative to the LH injection. This GnRH agonist-LH protocol provides a model for studying the gonadotrophin requirements for follicular growth and oocyte maturation in cattle, and will enable controlled in vivo maturation of oocytes before recovery for in vitro procedures.

Disruption of the Pituitary Circadian Clock Induced by Hypothyroidism and Hyperthyroidism: Consequences on Daily Pituitary Hormone Expression Profiles.

The secretion of pituitary hormones oscillates throughout the 24-hour period, indicating that circadian clock-mediated mechanisms regulate this process in the gland. Additionally, pituitary hormone synthesis has been shown to be altered in hypo- and hyperthyroidism. Although thyroid hormones can modulate the other peripheral clocks, the interaction between thyroid hormone levels and circadian clock gene expression in the anterior pituitary has yet to be elucidated. Male Wistar rats were divided into three groups: control, hypothyroid, and hyperthyroid. Following the experimental procedures, animals were euthanized every three hours over the course of a 24-hour period. The anterior pituitary glands were excised and processed for mRNA expression analysis by quantitative reverse transcriptase polymerase chain reaction. One- and two-way analysis of variance as well as cosinor analysis were used to evaluate the time-of-day-dependent differential expression for each gene in each experimental group and their interactions. Hyperthyroidism increased the mRNA expression of core clock genes and thyrotrophic embryonic factor (Tef), as well as the mesor and amplitude of brain and muscle Arnt-like protein-1 (Bmal1) and the mesor of nuclear receptor subfamily 1 (Nr1d1) group D member 1, when compared to euthyroid animals. Hypothyroidism disrupted the circadian expression pattern of Bmal1 and period circadian regulator 2 (Per2) and decreased the mesor of Nr1d1 and Tef. Furthermore, it was observed that the pituitary content of Dio2 mRNA was unaltered in hyperthyroidism but substantially elevated in hypothyroidism during the light phase. The upregulated expression was associated with an increased mesor and amplitude, along with an advanced acrophase. The gene expression of all the pituitary hormones was found to be altered in hypo- and hyperthyroidism. Moreover, prolactin (Prl) and luteinizing hormone beta subunit (Lhb) displayed circadian expression patterns in the control group, which were disrupted in both the hypo- and hyperthyroid states. Taken together, the data demonstrate that hypo- and hyperthyroidism alter circadian clock gene expression in the anterior pituitary. This suggests that triiodothyronine plays an important role in the regulation of pituitary gland homeostasis, which could ultimately influence the rhythmic synthesis and/or secretion of all the anterior pituitary hormones.

Characterization of carp gonadotropins: Structure, annual profile, and carp and zebrafish pituitary topographic organization

Two gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH), are important players in the hypothalamic-pituitary-gonadal axis of vertebrates. In the present work, we describe the construction of recombinant (r) common carp (Cyprinus carpio; c) FSH (rcFSH) and LH (rcLH) using the Pichia pastoris system, the generation of specific antibodies against their respective β subunits, and their use in the development and validation of specific ELISAs. We produced carp rLH and rFSH as single-chain polypeptides, wherein the GTH subunit α was joined with either cLHβ or cFSHβ mature protein-coding sequences to form a fusion gene that encodes a yoked polypeptide, in which the GTH β-subunit forms the N-terminal part and the α-subunit forms the C-terminal part. Competitive ELISAs were developed, using primary antibodies against rcLHβ or rcFSHβ, respectively, and rcLHβα or rcFSHβα for the standard curves. The standard curves for cLH paralleled those of pituitary extracts of the homologous fish and also those of other cyprinids species like the black carp (Mylopharyngodon piceus), goldfish (Carassius auratus), silver carp (Hypophthalmichthys molitrix), and grass carp (Ctenopharyngodon idella). We used the specific antibodies raised against cFSH and cLH to study the specific localization of the different GTH cells in the pituitary of carp and its taxonomic relative species – the zebrafish. Both FSH and LH cells are localized in the center of the proximal pars distalis enveloping both sides of the neurohypophysis. LH cells form a continuous population throughout the PPD, while FSH cells are more loosely distributed throughout the same area and form small aggregations. Marked annual changes were encountered in gonadosomatic index (GSI), follicle diameter, mRNA levels and protein levels of FSH and LH. From September to November, all fish had low GSI, and the ovary contained previtellogenic follicles. From December, the GSI level increased and remained high until March, the follicular diameter reached its maximum in January, where the ovary contained large fully grown follicles. Thereafter, spawning occurred through March and April and ended in May, and GSI level and follicle diameter increased again; and the ovary contained mid-vitellogenic follicles. LH pituitary content and mRNA levels were low at pre- and early vitellogenesis, increasing gradually during this process to reach a peak of LH mRNA levels in mid vitellogenic ovary and a peak of LH content in fully grown ovarian follicles. However, no significant change occurred in FSH pituitary content and mRNA levels in vitellogenic fish and in fish during final maturation stages. A dramatic difference was found in the total content of each gonadotropin in the pituitary, with higher LH than FSH. Moreover, follicle diameter was positively and significantly correlated with LH pituitary content and its transcript levels – but not with the pituitary content or mRNA levels of FSH. Taken together, these results indicate that in carp, LH alone is sufficient to regulate both vitellogenesis and final oocyte maturation while FSH may have another, yet undefined role.

Vasopressin Regulation and Potassium Homeostasis Following Recovery from Severe Blood loss in a Conscious Rat Model of Hemorrhagic Shock

In an anesthetized, mechanically ventilated pig model, we have found that non‐survival in the first minutes after severe hemorrhage is associated with a rapid elevation in plasma potassium (K) and a blunted endogenous vasopressin(VP) response in non‐survivors compared to survivors. We have also shown that exogenously administered VP during hemorrhage resuscitation causes a dramatic increase in urine flow and can increase the fractional excretion of K compared to other pressor agents. Thus, early survival of acute rapid blood loss in severe hemorrhage may depend on the ability of VP to regulate renal normalization of circulating plasma K levels. It is unknown what may prevent an adequate endogenous VP response that would allow renal K excretion to be maintained in the face of low urine output during hemorrhage‐induced hypotensive shock. Aside from responding only to hypotension and hyperkalemia, other factors of electrolyte or acid‐base balance may also affect VP regulation of K balance. Thus, in this study, we tested the hypothesis that VP regulation may be affected by other fluid and electrolyte changes that occur in different stages of hemorrhage induced‐shock, resuscitation, and recovery. Hence, we examined circulating VP and K levels in the face of changes in acid‐base homeostasis in a conscious rat model where animals are able to adjust spontaneously breathing in response to hemorrhage. Renal K handling and regulation of VP in rats (n=35) were compared before, during, and after hemorrhage(2 ml shed blood/100 g body weight), one hour after hemorrhage resuscitation with normal saline, and 3 and 7 days after hemorrhage. Hematocrit (Hct) was 36±1%, 27±1%,25±1%,29±1%, 37±1 % at baseline, hemorrhage, resuscitation, 3 days and7 days post‐hemorrhage, respectively. Plasma K increased (3.61±0.07 to 4.27±0.13mEq/L, p&lt;0.05) and urine K levels increased (86±8 to 190±9 mEq/L, p&lt;0.05)during hemorrhage. An increased renal trans‐tubular K gradient during hemorrhage and resuscitation (10.7 ± 0.5 to 16.4 ± 0.9, p&lt;0.05) occurred co‐incident with a 7‐fold the increase in plasma VP with hemorrhage, and returned to baseline levels with resuscitation. Multiple regression analysis of indices of blood gases and electrolytes during post‐hemorrhage recovery when Hct had not yet returned to normal, revealed that VP levels were correlated with plasma K, blood pH and oxygen saturation. Indicative of the stimulation of VP release and renal action during hemorrhage, VP pituitary content, renal V2 receptor mRNA expression and pituitary V1b receptor mRNA expression 7days after recovery correlated with vasopressin responses at different timepoints after hemorrhage. Results support an important role for VP in protecting against hyperkalemia in hemorrhagic shock, with VP responsiveness being influenced by changes in blood gases and acid‐base regulation.Support or Funding InformationThe views expressed in this abstract are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US government

Pituitary Gland: Normal Function and Assessment.

This computer-based, interactive module introduces preclinical medical students to normal pituitary function and outlines its assessment. Solid understanding of these topics is requisite to learning clinical disorders of the pituitary. Existing resources largely target learners at earlier or later stages of training; thus, we created this resource to address needs of medical students during a first- or second-year endocrine course. A module format was selected to promote interactive, independent learning. Two cohorts of medical students completed the 40-minute module: 172 second-year students who had completed a year of basic sciences in the traditional curriculum and 180 foundation-phase students in a three-semester combined basic and clinical sciences curriculum (due to a change in the medical school curriculum at our institution). In both instances, the module was completed before start of clinical pituitary content. A static set of PowerPoint slides accompanied the module to facilitate note taking. Test Your Knowledge slides were inserted to ensure grasp of key terms/concepts before moving to subsequent slides. A short question-and-answer session was held following module completion to clarify points of confusion. Students rated effectiveness of the module as 4.6 out of 5, commenting on its clarity, organization, high-yield nature, and utility in preparing for clinical material. Faculty noted greater understanding of foundational pituitary principles and more engaging discussions. The percentage of pituitary-related questions answered correctly on the midterm exam increased. The success of the pituitary module prompted development of adrenal, thyroid, and parathyroid modules that now comprise the Endocrine Organs Introduction Series in our curriculum.

Effects of Estradiol-17β or Dihydrotestosterone on Cell Types in Equine Pituitaries Staining for Prolactin, Growth Hormone, or Both

Ovariectomized pony mares were treated with vehicle (controls), estradiol-17β (estradiol), or dihydrotestosterone (DHT) daily for 21 days in summer, and the pituitary content of prolactin and growth hormone (GH) and the numbers of cells staining immunocytochemically for prolactin (lactotropes), GH (somatotropes), or both hormones (mammosomatotropes) were assessed. Treatments did not alter (P > .1) plasma prolactin concentrations over the 21 days. Estradiol treatment increased (P < .05) the pituitary content of prolactin several-fold relative to controls and DHT-treated ponies. The number of lactotropes was also increased (P < .05), as was the number of mammosomatotropes (P < .05). Treatment with DHT did not alter (P > .1) any prolactin characteristic. The number of somatotropes was not altered by either treatment (P > .1) nor was the pituitary content of GH (P > .1). Given that the mass of prolactin accumulation in the pituitary in response to estradiol was several-fold greater than the approximate doubling of the number of lactotropes and mammosomatotropes, it appears that estradiol administration to ovariectomized pony mares stimulates not only the number of prolactin-producing cells but also the amount of prolactin production per cell.

Development of a homologous radioimmunoassay for red seabream follicle stimulating hormone and regulation of gonadotropins by GnRH in red seabream, Pagrus major

Using a recombinant chimeric single-chain follicle stimulating hormone (FSH), we established a radioimmunoassay (RIA) for red seabream (Pagrus major) FSH (pmFSH) which became a powerful tool for studying reproductive physiology. We studied the profiles in plasma and pituitary concentrations of FSH and luteinizing hormone (LH) during sexual maturation. A pre-established RIA for red seabream LH was used for the LH measurements. The regulation of FSH and LH secretion from the pituitary was investigated using a gonadotropin-releasing hormone analog (GnRHa) in vivo and in vitro. Marked differences in plasma and pituitary FSH levels were observed between males and females; pituitary FSH content in males was much higher than that in females during all seasons, and plasma FSH levels in males were high during the spawning season, whereas those in females were unchanged. In contrast, plasma and pituitary levels of LH were elevated before and during the spawning season in males and females. Injecting or implanting (cholesterol pellet) a GnRHa into adult and juvenile red seabream resulted in significant increases in plasma LH concentrations; however, no significant change was observed in plasma FSH. Moreover, GnRHa stimulated only LH secretion in an in vitro experiment using dispersed pituitary cells. The discrete FSH and LH secretion profiles revealed suggest differential roles for the two gonadotropins during red seabream gametogenesis. In addition, the marked difference in pituitary FSH levels in males and females suggests the relative significance of FSH in male reproduction.

Is the kisspeptin system involved in responses to food restriction in order to preserve reproduction in pubertal male sea bass (Dicentrarchus labrax)?

Previous works on European sea bass have determined that long-term exposure to restrictive feeding diets alters the rhythms of some reproductive/metabolic hormones, delaying maturation and increasing apoptosis during gametogenesis. However, exactly how these diets affect key genes and hormones on the brain–pituitary–gonad (BPG) axis to trigger puberty is still largely unknown. We may hypothesize that all these signals could be integrated, at least in part, by the kisspeptin system. In order to capture a glimpse of these regulatory mechanisms, kiss1 and kiss2 mRNA expression levels and those of their kiss receptors (kiss1r, kiss2r) were analyzed in different areas of the brain and in the pituitary of pubertal male sea bass during gametogenesis. Furthermore, other reproductive hormones and factors as well as the percentage of males showing full spermiation were also analyzed. Treated fish fed maintenance diets provided evidence of overexpression of the kisspeptin system in the main hypophysiotropic regions of the brain throughout the entire sexual cycle. Conversely, Gnrh1 and gonadotropin pituitary content and plasma sexual steroid levels were downregulated, except for Fsh levels, which were shown to increase during spermiation. Treated fish exhibited lower rates of spermiation as compared to control group and a delay in its accomplishment. These results demonstrate how the kisspeptin system and plasma Fsh levels are differentially affected by maintenance diets, causing a retardation, but not a full blockage of the reproductive process in the teleost fish European sea bass. This suggests that a hormonal adaptive strategy may be operating in order to preserve reproductive function in this species.

Effects of Short Term Administration of Genistein on Hypothalamic and Anterior Pituitary Hormones in Ovariectomized Gilts

Administration of genistein to barrows increased anterior pituitary (AP) concentrations of IGF-I and LH and increased expression of AP IGF receptor. Whether similar changes occur in gilts remains to be determined. The objective of this experiment was to determine if short term administration of genistein increased expression of components of the AP IGF system and hypothalamic hormones and receptors involved in gonadotropin synthesis and/or release in the gilt. Sixteen crossbred gilts of similar weight (97.7 kg) were ovariectomized and assigned to either control (C; n = 8) or genistein (G; n = 8) groups. Genistein pigs received 800 mg of genistein in DMSO while C pigs received an equal volume of DMSO i.m. on day 0, 1, 2, and 3. Blood samples were obtained on day 0, 1, 2, and 3. Pigs were slaughtered on d 4 when blood, AP, and medial basal hypothalami (MBH) were collected. No difference was detected (P > 0.05) in AP concentrations of IGF-I or serum concentrations of IGF-I in C and G pigs. Anterior pituitary concentrations of LH were greater (P 0.05) in C and G pigs. Relative expression of AP IGFBP-5 and GnRHR was increased (P < 0.05) in G pigs compared with C pigs. Relative expression of AP LHβ did not differ between C and G pigs. Relative expression of MBH kisspeptin was greater (P < 0.01) in G pigs than C pigs. These data provided evidence that short term administration of genistein increased expression of hypothalamic and hypophyseal hormones in gilts which could influence subsequent reproduction.

Discovery of Characteristics of Patients with Increased Level of Inflammation

This paper is a study on knowledge discovery for the prediction of characteristics of older patients with increased level of inflammation. The etiology of inflammation is thought to be multifactorial and associated with the development of chronic aging diseases. Chronic low grade inflammation, expressed by slightly elevated serumconcentrations of the inflammatory marker C-reactive protein (CRP), has been showed to be associated with increased frailty and overall and specific cardiovascular and noncardiovascular mortality. However, it has not been discovered before which conditions, taken all at once, are associated with elevated systems level of inflammation. To answer this question, we used the group of older primary health care attenders, burdened with multiple chronic conditions and described their health status by many aspects. The dataset was composed of 61 low-cost health parameters, many of which were data from patient health records. To predict the characteristics of patients with increased level of inflammation, we used a Linear Regression model and compared the results with some classfication algorithms. In this way, we selected 11 relevant predictors of inflammation and explained their meaning according to the existing knowledge. We could realise that many of them represent the components of the highly conserved functional network in which inflammation is the intermediate mechanism, linking these components together. These components include the metabolic, the neuroendocrineand the immune system, proposed as influencing each other during the development of age-related chronic diseases. We have also identified some new components, represented by the parameters indicating inflammation-mediated locomotor system disorders and the pituitary hormone prolactin serum concentration variations. This model, resulted from the knowledge discovery procedure, can be used to provide guidelines for further research on chronic low grade inflammation and for more practical purposes, to help physicians recognizing older persons who are at increased risk for frailty and death.

Pituitary gonadotrophic hormone synthesis, secretion, subunit gene expression and cell structure in normal and follicle-stimulating hormone β knockout, follicle-stimulating hormone receptor knockout, luteinising hormone receptor knockout, hypogonadal and ovariectomised female mice.

To investigate the relationship between gonadotroph function and ultrastructure, we have compared, in parallel in female mice, the effects of several different mutations that perturb the hypothalamic-pituitary-gonadal axis. Specifically, serum and pituitary gonadotrophin concentrations, gonadotrophin gene expression, gonadotroph structure and number were measured. Follicle-stimulating hormone β knockout (FSHβKO), follicle-stimulating hormone receptor knockout (FSHRKO), luteinising hormone receptor knockout (LuRKO), hypogonadal (hpg) and ovariectomised mice were compared with control wild-type or heterozygote female mice. Serum levels of LH were elevated in FSHβKO and FSHRKO compared to heterozygote females, reflecting the likely decreased oestrogen production in KO females, as demonstrated by the threadlike uteri and acyclicity. As expected, there was no detectable FSH in the serum or pituitary and an absence of expression of the FSHβ subunit gene in FSHβKO mice. However, there was a significant increase in expression of the FSHβ and LHβ subunit genes in FSHRKO female mice. The morphology of FSHβKO and FSHRKO gonadotrophs was not significantly different from the control, except that secretory granules in FSHRKO gonadotrophs were larger in diameter. In LuRKO and ovariectomised mice, stimulation of LHβ and FSHβ mRNA, as well as serum protein concentrations, were reflected in subcellular changes in gonadotroph morphology, including more dilated rough endoplasmic reticula and fewer, larger secretory granules. In the gonadotophin-releasing hormone deficient hpg mouse, gonadotrophin mRNA and protein levels were significantly lower than in control mice and gonadotrophs were correspondingly smaller with less abundant endoplasmic reticula and reduced numbers of secretory granules. In summary, major differences in pituitary content and serum concentrations of the gonadotrophins LH and FSH were found between control and mutant female mice. These changes were associated with changes in expression of the gonadotrophin subunit genes and were reflected in the cellular structure and secretory granule appearance within the gonadotroph cells.

Pharmacokinetics, tissue distribution, and excretion of nomegestrol acetate in female rats.

Nomegestrol acetate (NOMAC), a synthetic progestogen derived from 19-norprogesterone, is an orally active drug with a strong affinity for the progesterone receptor. NOMAC inhibits ovulation and is devoid of undesirable androgenic and estrogenic activities. The aim of this study was to evaluate the pharmacokinetics, tissue distribution, and excretion of NOMAC in female rats. Sprague-Dawleyfemale rats were orally administered a single dose of NOMAC (10, 20 or 40mg/kg) and drug plasma concentrations at different times were determined by RP-HPLC. Tissue distribution at 1, 2, and 4h and excretion of NOMAC into bile, urine, and feces after dosing were investigated. The results showed that NOMAC was rapidly absorbed after oral administration, with [Formula: see text] of 1-2h. The plasma concentration-time curves were fitted in a two-compartment model. The exposure to NOMAC ([Formula: see text] and [Formula: see text]) increased dose proportionally from 10 to 40mg/kg. The average CL and [Formula: see text] were 5.58L/(h·kg) and 10.8h, respectively. The highest concentrations of NOMAC in ovary, liver, kidney, lung, heart, brain, spleen, muscle, and uterus were observed at 2h, whereas the highest concentrations in stomach, pituitary, and hypothalamus appeared at 1h. The total cumulative excretion of NOMAC in feces (0-72h), urine (0-72h), and bile (0-48h) was ~1.06, 0.03, and 0.08% of the oral administered dose, respectively. This study indicated that NOMAC had a widespread distribution in tissues, including ovary, pituitary, and hypothalamus, which are main target tissues where NOMAC inhibits ovulation. NOMAC was excreted via both feces and urine with few unchanged NOMAC excreted. Enterohepatic circulation was found in the drug elimination; however, it did not significantly affect [Formula: see text].

Prolactin and upstream migration of the amphidromous teleost, ayu Plecoglossus altivelis.

Changes in mRNA levels of prolactin (PRL) during the upstream migration were examined in fry of the amphidromous fish, ayu Plecoglossus altivelis. Quantification of mRNA has been done with real-time PCR and expressed as whole body or pituitary contents depending the body size of fry. PRL mRNA levels of ayu caught in seawater of the coastal area remained low during early spring. Prior to the start of the upstream migration, the fish caught in the coastal area in mid spring showed increased levels of PRL mRNA. There were further increases in PRL levels in the fish caught in the river. Analysis of proportions revealed that there were significant differences among PRL mRNA in the fish caught in different environmental salinities. Body weight showed a positive relation with PRL mRNA in ayu caught in seawater. A landlocked population of ayu, which migrates from lake to river, showed no significant change in PRL mRNA levels before and after upstream migration. Results in this study indicate the importance of up-regulation of PRL gene expression of ayu during the upstream migration from seawater to fresh water. There is a possible relationship between body size and PRL in the early developmental stage of ayu in seawater, but not in the fish in fresh water.

An early reduction in GH peak amplitude in preproghrelin-deficient male mice has a minor impact on linear growth.

Ghrelin is a gut hormone processed from the proghrelin peptide acting as the endogenous ligand of the GH secretagogue receptor 1a. The regulatory role of endogenous ghrelin on pulsatile GH secretion and linear growth had to be established. The aim of the present study was to delineate the endogenous actions of preproghrelin on peripheral and central components of the GH axis. Accordingly, the ultradian pattern of GH secretion was measured in young and old preproghrelin-deficient males. Blood samples were collected by tail bleeding every 10 minutes over a period of 6 hours. Analysis of the GH pulsatile pattern by deconvolution showed that GH was secreted in an ultradian manner in all genotypes, with major secretory peaks occurring at about 3-hour intervals. In older mice, the peak number was reduced and secretion was less irregular compared with younger animals. Remarkably, in young Ghrl(-/-) mice, the amplitude of GH secretory bursts was significantly reduced. In older mice, however, genotype differences were less significant. Changes in GH pulsatility in young Ghrl(-/-) mice were associated with a tendency for reduced GH pituitary contents and plasma IGF-I concentrations, but with only a minor impact on linear growth. In Ghrl(+/-) mice, despite reduced Acyl ghrelin to des-acyl ghrelin ratio, GH secretion was not impaired. Ghrelin deficiency was not associated with a reduction in hypothalamic GHRH content or altered response to GHRH stimulation. Therefore, reduction in GHRH production and/or sensitivity do not primarily account for the altered GH pulsatile secretion of young Ghrl(-/-) mice. Instead, GHRH expression was elevated in young but not old Ghrl(-/-) mice, suggesting that differential compensatory responses resulting from the absence of endogenous ghrelin is occurring according to age. These results show that endogenous ghrelin is a regulator of GH pulse amplitude in growing mice but does not significantly modulate linear growth.