Changes In Endocrine Activity Research Articles

Fecal glucocorticoid analysis as a health monitoring tool for endangered African penguins (Spheniscus demersus)

African penguins (Spheniscus demersus) are an endangered species, with approximately 70,000 mature adults remaining in the wild. Population loss is linked to a combination of environmental and anthropogenic stressors. The aim of the study was to validate a commercially available enzyme immunoassay (EIA) to assess adrenal activity and measure the response to stressors in the feces of African penguins. Fecal samples (n = 609) were collected from 12 African penguins housed at Mystic Aquarium throughout their natural lifecycle, including breeding and molt, where measurable changes in fecal glucocorticoid metabolite (FGM) levels are predicted to occur. Fecal samples collected post-veterinary exam were used for biological validation. Longitudinal analysis shows a significant difference (p = <0.0001) between the average FGM levels during baseline and breeding season, 33.97 ± 1.30 ng/g and 50.21 ± 3.18 ng/g, respectively. Females displayed significantly higher FGM levels than males during both baseline (p = 0.0386; females = 38.80 ± 2.19 ng/g; males = 29.34 ± 1.37 ng/g) and breeding periods (p = 0.0175; females = 57.53 ± 4.84 ng/g; males = 42.69 ± 3.95 ng/g). Average FGM levels decreased significantly over the three-week molting period, from 85.40 ± 20.35 ng/g at week one to 20.23 ± 5.30 ng/g at week three. A seasonal difference in FGM levels was observed in both male and female fecal samples, with Fall having the highest average FGM levels, 54.38 ± 3.64 ng/g, and Summer the lowest, 30.87 ± 2.21 ng/g. General linear mixed model analysis determined that lifecycle (females) and visitor presence (males) were the two factors which best explained the variation in FGM levels observed, however neither factor was found to be significant. These results show FGM analysis can detect physiologically meaningful changes in endocrine activity in African penguins and can be used to monitor health for penguins in aquaria and in the wild, thus contributing to conservation efforts for the survival of the species.

Endogenous oxytocin, cortisol, and testosterone in response to group singing

Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking—particularly when performed together—and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.

Seasonal Changes in Plasma Hormones, Sex-Related Genes Transcription in Brain, Liver and Ovary during Gonadal Development in Female Rainbow Trout (Oncorhynchus mykiss)

The purpose of this study was to investigate the periodic seasonal changes in endocrine activity and gonadal development of female rainbow trout (Oncorhynchus mykiss) in a high-altitude cold-water environment. The fish were sampled monthly from January to November and the levels of plasma hormones (estradiol (E2), cortisol and thyroid hormones (THS)) and vitellogenin (VTG) were measured by ELISA. Moreover, the transcriptions of sex-related genes in the ovary, brain, and liver were detected by qRT-PCR. The results showed a seasonal fluctuation of plasma hormones and VTG together with the development of the ovary, which reached a peak from August to October. Similarly, the transcription of hypothalamic gonadotropin-releasing hormone-2 (cgnrh-2), hypothalamic gonadotropin-releasing hormone receptors (gnrhr) and follicle-stimulating hormone (fsh) in the brain varied from January to September, but the highest level was detected in September to November. In addition, the transcription of sex-related genes located in the ovary and liver increased significantly during August to October, accompanied by a continuous increase in the gonadosomatic index (GSI) and a decrease in the hepatosomatic index (HSI). Therefore, plasma hormones and sex-related genes regulate the development and maturation of O. mykiss oocytes with the change in seasons and peaked in November. The results of this study provide a reference for improving the efficiency of the artificial reproduction of O. mykiss.

When your host shuts down: larval diapause impacts host-microbiome interactions in Nasonia vitripennis

BackgroundThe life cycles of many insect species include an obligatory or facultative diapause stage with arrested development and low metabolic activity as an overwintering strategy. Diapause is characterised by profound physiological changes in endocrine activity, cell proliferation and nutrient metabolism. However, little is known regarding host-microbiome interactions during diapause, despite the importance of bacterial symbionts for host nutrition and development. In this work, we investigated (i) the role of the microbiome for host nutrient allocation during diapause and (ii) the impact of larval diapause on microbiome dynamics in the parasitoid wasp Nasonia vitripennis, a model organism for host-microbiome interactions.ResultsOur results demonstrate that the microbiome is essential for host nutrient allocation during diapause in N. vitripennis, as axenic diapausing larvae had consistently lower glucose and glycerol levels than conventional diapausing larvae, especially when exposed to cold temperature. In turn, microbiome composition was altered in diapausing larvae, potentially due to changes in the surrounding temperature, host nutrient levels and a downregulation of host immune genes. Importantly, prolonged larval diapause had a transstadial effect on the adult microbiome, with unknown consequences for host fitness. Notably, the most dominant microbiome member, Providencia sp., was drastically reduced in adults after more than 4 months of larval diapause, while potential bacterial pathogens increased in abundance.ConclusionThis work investigates host-microbiome interactions during a crucial developmental stage, which challenges both the insect host and its microbial associates. The impact of diapause on the microbiome is likely due to several factors, including altered host regulatory mechanisms and changes in the host environment.8eXiSqX1W-a7vPRfczqREZVideo .

Computations of uncertainty mediate acute stress responses in humans.

The effects of stress are frequently studied, yet its proximal causes remain unclear. Here we demonstrate that subjective estimates of uncertainty predict the dynamics of subjective and physiological stress responses. Subjects learned a probabilistic mapping between visual stimuli and electric shocks. Salivary cortisol confirmed that our stressor elicited changes in endocrine activity. Using a hierarchical Bayesian learning model, we quantified the relationship between the different forms of subjective task uncertainty and acute stress responses. Subjective stress, pupil diameter and skin conductance all tracked the evolution of irreducible uncertainty. We observed a coupling between emotional and somatic state, with subjective and physiological tuning to uncertainty tightly correlated. Furthermore, the uncertainty tuning of subjective and physiological stress predicted individual task performance, consistent with an adaptive role for stress in learning under uncertain threat. Our finding that stress responses are tuned to environmental uncertainty provides new insight into their generation and likely adaptive function.

The neuroendocrine regulation's features of the inflammatory process in bronchial asthma

Event Abstract Back to Event The neuroendocrine regulation's features of the inflammatory process in bronchial asthma Alexandr V. Zhukov1 and Anatoliy P. Godovalov1* 1 Acad. E.A. Wagner Perm State Medical University, immunology, Russia Chronic inflammation is a key factor of pathogenesis of many diseases. It is known that the autonomic nervous system (ANS) takes part in an inflammatory process by the regulation of effector cells functions and redistribution of energy in the immune system. Patients with autoimmune, infectious and other diseases have a dysfunction of ANS. This could be primary dysfunction because it leads to overproduction of proinflammatory cytokines in response to the specific antigens [2]. It is considered that the sympathetic nervous system's (SNS) activity increases during inflammation what is necessary for the energy supply of the immune system. On the other hand a parasympathetic dysfunction leads to reduction of Th1-response which is necessary for an adequate inflammatory process and elimination of the pathogen [4]. This is realized by the interaction between nervous and immune systems. It is known that immune cells have got receptors to neuropeptides: acetylcholine, dopamine, enkephalins and endorphins. At the same time immune cells can synthesize neuropeptides and respond to most of substances from this group. Nervous cells can synthesize some cytokines and respond to them. That's why this systems can be considered to use the same number of signal molecules or they've got intersecting signal ways for intersystem communication.In this connection the research of features and activity of inflammation in people with different types of ANS during diseases is interesting. The purpose of research is the study of leukocytes structure and biochemical parameters of peripheral blood in patient with asthma depending on ANS type. Materials and methods. There were 15 patients with asthma. We counted leukocytes, glucose concentration, proteins, C-reactive protein and transaminases in peripheral blood. ANS type was determined by Vein's method [1]. Statistical analysis was performed with using Student's t-test. Results. Studies revealed that patients with sympathetic type of ANS were treated in hospital for 17.0±1.6 days but patients with parasympathetic type of ANS were treated for 21.0±2.0 days (p<0.05). The leukocytes structure in peripheral blood doesn't differ in patients with different types of ANS. Erythrocytes sedimentation rate was higher in patients with parasympathetic type – 20.5±2.5 mm/h (in patients with sympathetic type – 12.1±3.4 mm/h; p<0.05). C-reactive protein was higher in patients with parasympathetic type – 22.2±1.8 mg/l (in patients with sympathetic type – 9.3±3.3 mg/l; p<0.05). Discussion. The research has shown that patients with the parasympathetic type of ANS have got more expressed signs than patients with the sympathetic type. It is shown that the products of activated proinflammatory cells could stimulate neuronal synapses what causes long-term neuronal activity's changes and this leads to changes in endocrine activity of ANS [7]. The number of sympathetic fibres is reduced in inflamed tissue it leads to proinflammatory signals reduction and with production of neuropeptides from sensitive neural fibres this leads to local inflammation. In case of an acute inflammation this configuration promotes antigen releasing. But in case of chronic process these changes leads to constant redistribution of energy and continuous local destruction[5]. Lujan H.L. and co-authors have shown in their research that increas of parasympathetic activity may be used as therapeutic strategy for inhibition and prevention of a chronic inflammation [3]. Activation of the cholinergic anti-inflammatory signaling pathway contributes to a significant improvement in case of such cytokine-mediated diseases as sepsis, colitis, pancreatitis etc [6]. Conclusion. Thus our research has revealed that inflammatory activity depends on the type of ASN. The changes of activity of ANS may be a perspective therapeutic method treating of inflammatory processes.

Leptin responses to bovine interferon- α and insulin in cattle

Leptin is a protein synthesized and secreted mainly by adipose tissue. Peripheral administration of different inflammatory cytokines increases both leptin protein and mRNA expression in rodents. We previously showed that injection of lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNF-&#945;) did not affect leptin secretion in both sheep and cows. IFN- &#945; is one of cytokines that mediate metabolic and endocrine activity in animals and humans. We used IFN- &#945; because it is wildly used in humans for treatment of hepatitis. The aim of this study was to test whether the changes in endocrine activity were accompanied by changes in leptin secretion after IFN injection. Recombinant IFN- &#945; (106 unit/kg ) was injected intravenously (i.v) to Holstein cattle. Plasma was collected 30 minutes after injection and continued for 8 hours. IFN- &#945; injection produced a rapid increase in glucose and insulin levels but leptin levels did not show any alteration after the injection. Insulin is known as a potent stimulant of leptin secretion and expression, so we tested the effect of bovine insulin in a dose of 0.2 U/kg on leptin secretion. Insulin levels rapidly increased in the blood and consequently a significant decrease in blood glucose level was recorded. However, this increase in insulin did not affect leptin secretion. To confirm the leptin response to insulin, mature adipocytes were isolated from abdominal adipose tissue of 3 cows and incubated for 24 h with insulin in vitro. Insulin stimulated leptin expression in dose dependent manner with peak expression at 100 nM concentration. These results, strongly postulate that leptin secretion in cattle is quite different from those reported in humans and rodents. Keywords: Leptin, Insulin, Cytokines, Cattle . Egyptian Journal of Biochemistry and Molecular Biology Vol. 26 (1) 2008 pp. 67-82

Hormonal Correlates of Environmentally Induced Metamorphosis in the Western Spadefoot Toad,Scaphiopus hammondii

Tadpoles of several amphibian species have been shown to accelerate metamorphosis when their ponds dry. To understand the proximate mechanisms that mediate the developmental response to pond drying, I analyzed changes in endocrine activity in tadpoles of the Western spadefoot toad (Scaphiopus hammondii) exposed to experimental water volume reduction in the laboratory. Tadpoles exposed to a declining water level accelerated metamorphosis compared with tadpoles raised in a constant high water environment. The acceleration of development was associated with the precocious elevation of whole-body contents of the hormones that control metamorphosis, the thyroid hormones thyroxine (T4) and triidothyronine (T3), and the interrenal steroid corticosterone (CORT). The precocious activation of the thyroid system preceded external morphological change (i.e., increase in hind limb length, developmental stage) by 3 days. To test if tadpoles are capable of responding rapidly to water volume reduction, mid-prometamorphic tadpoles (Gosner Stage 37–38) were raised in a constant high water environment (10 L) and then transferred to either 1 or 10 L. Tadpoles transferred to 1 L exhibited significant metamorphic changes by 48 h after transfer. In addition, dramatic elevations in whole-body T4, T3, and CORT contents were evident at this time point. Thus, the metamorphic response to pond drying is likely driven by the activation of the thyroid and interrenal axes, the hormones of which control metamorphosis. Furthermore, this response is rapid, occurring within 48 h after exposure to the desiccating environment.

Aminoglutethimide-stimulated corticotrophs

Thirty-six rats of both sexes in two groups were treated with aminoglutethimide (AG), a steroid synthesis inhibitor, for 1 and 8 weeks respectively. The anterior pituitaries were investigated by light and electron microscopy, the techniques used including immunocytochemical and morphometric methods. Corticotrophs were identified by the avidinbiotin-peroxidase complex technique at the light and electron microscopic levels. AG administration resulted in hyperplasia of ACTH-containing cells. The increase in the volume density of corticotrophs was prevented by simultaneous medication with 3 mg corticosterone in male rats, whereas in female rats a larger dose of corticosterone was required to suppress pituitary corticotroph hyperplasia. Electron microscopy revealed that in AG-treated rats, corticotrophs were larger and contained more secretory granules than those in controls, the mean secretory granule diameter increasing from 100 nm to 165 nm. Under AG stimulation, corticotrophs showed considerable variations in structural features probably reflecting differences in their functional state. It was apparent that only one ACTH-producing cell type existed in the pars distalis of the rat adenohypophysis, although this cell type may undergo substantial morphologic alterations due to changes in endocrine activity. Gonadotrophs and thyrotrophs showed morphologic signs of stimulation and exhibited hyperplasia following AG treatment indicating that the effect of the drug was not restricted to corticotrophs.

Role of endocrine factors in chronic congestive heart failure, with emphasis on catecholamines.

Changes in endocrine activity in response to tilting of the body were studied in 16 in-patients with various degrees of chronic congestive heart failure and one healthy subject. Norepinephrine and epinephrine excretion, plasma renin activity and plasma cortisol concentration were determined first in recumbency and then during 45 degree head-up tilting. The subjects were divided into three groups depending on the severity of heart failure. In recumbency urinary norepinephrine averaged 31.6 (standard deviation 12.7) ng/min in group 1 (controls), 54.9 +/- 25.3 ng/min in group 2 (NYHA class II--III) and 79.5 ng/min in group 3 (NYHA class IV). Thus the level of urinary norepinephrine increased with the degree of heart failure. In recumbency epinephrine excretion and plasma cortisol concentration were not different among three groups. Plasma renin activity was elevated in group 3. There was a significant positive correlation between the changes in plasma renin activity and epinephrine secretion (r = 0.67, p less than 0.01). The present study revealed that patients with slight to moderate congestive heart failure have a normal endocrine response to tilting while those in severe failure have only a slight response. It is probable that the augmented sympathetic nerve activity and increased circulating blood volume, already present in severe failure, allow for less hemodynamic change upon tilting.

Persistence of relapse of morphine-seeking behavior in rats: the relative role of certain biological variables.

The theory that narcotic-induced protracted biological changes are responsible for relapse of opiate-reinforced behavior was examined in the rat. Groups of rats were conditioned to prefer a distinctive environment by pairing it with morphine doses from 1-200 mg/kg, and were retested for persistence of this preference after a 3-week abstinence period. They were then observed for protracted signs such as sensitivity to naloxone, tolerance to morphine analgesia, hyperaggression, or changes in endocrine activity. Acquisition and relapse of the preference, as well as long-term tolerance, were dose related. None of the purported protracted signs showed any consistent relationship to the tendency to relapse. However, relapse correlated significantly with original acquisition scores in all relapsing groups. The results suggest that original conditioning factors, rather than protracted changes, are responsible for the observed relapse.

Interrelationships Between the Endocrine System and Neuropsychiatry

Publisher Summary This chapter discusses the experimental basis for the control of changes in pituitary-adrenocortical activity as it impinges upon psychiatry and the role of other endocrines is merely touched. The subject is considered from two main points of view, which are (i) the psychiatric symptomatology occurring in endocrine disorder and (ii) the changes in endocrine activity occurring in psychiatric conditions. The introduction of ACTH and cortisone into therapeutics provided a very great impetus to basic research both in medicine and in endocrinology. This activity soon spread, particularly as the concept of stress developed, to psychiatry and psychosomatics. The chapter discusses the psychogenesis of endocrine disorder. A possible association between thyroid activity and some cases of schizophrenia was suggested by the reported success of thyroxine treatment in periodic catatonia, as well as by the discovery that a low basal metabolic rate (BMR) was common among schizophrenic patients. The psychological symptoms of hyperthyroidism are well known and are present in almost every case of the disease. Typically, they include emotional lability and over reactiveness with predominant anxiety and tension. Some patients are depressed and a few are euphoric. A very small group is indifferent and apathetic, showing the so-called apathetic form of hyperthyroidism

THE CONTROL OF NEUROSECRETION AND DIAPAUSE BY PHYSIOLOGICAL CHANGES IN THE BRAIN OF THE CECROPIA SILKWORM

1. The 26 neurosecretory cells in the brain of the Cecropia silkworm have been shown by Williams to undergo systematic changes in endocrine activity during metamorphosis. At the pupal molt the neurosecretory cells lose endocrine activity. Consequently, growth is checked and the animal enters pupal diapause. Endocrine activity is restored following prolonged exposure to low temperatures. When the brain hormone is released, diapause ends and the development of the adult moth begins.2. The electrical events in the brain as a whole have been studied in relation to these changes in endocrine activity. The larval brain shows abundant "spontaneous" electrical activity. However, on the day before the pupal molt the brain loses spontaneous activity and is no longer excited by direct electrical stimulation. The electrical silence of the brain persists throughout the months of diapause. Electrical activity reappears in the pupal brain a few days before the end of diapause.3. Cholinesterase (ChE) is present in high titer in the larval brain. However, two days before pupation the brain ChE begins a rapid decline, so at pupation ChE is undetectable in the brain. ChE does not reappear in the pupal brain until shortly before the recovery of electrical and endocrine activities. There is no evidence that an inhibitor of ChE is present in the diapausing brain. Evidently, ChE is absent or in low titer and is synthesized just before the onset of adult development.4. During diapause the cholinergic action of brain extracts steadily increases. The increase is slow in the brains of pupae stored at 25° C. and rapid in the brains of pupae stored at 15° or 6° C. Therefore the rate of accumulation of the cholinergic substance parallels the effectiveness of the temperature treatment in restoring the brain to endocrine activity.5. When ChE reappears in the brain, just before the onset of adult development, the titer of cholinergic substance in the brain falls to a low level. The low level is maintained until shortly before adult emergence, when the titer of cholinergic substance increases five-fold.6. Choline acetylase activity remains uniform in brain homogenates from unchilled and chilled pupae.7. The changes in electrical activity, ChE, and cholinergic substance during metamorphosis are peculiar to the brain. The ganglia of the ventral nerve cord retain normal function throughout diapause.8. ChE is synthesized in chilled pupal brains which are cultured at 25° C. in the absence of prothoracic glands. Under the same circumstances unchilled brains are unable to synthesize ChE. Moreover, exposure to the brain and the prothoracic gland hormones fails to promote the synthesis of ChE in unchilled pupal brains.9. ChE and electrical activity remain constant during the metamorphosis of Galleria, a non-diapausing insect. Two additional diapausing species, Telea polyphemus and Samia walkeri showed variations in brain ChE and electrical activity identical to those described in Cecropia.10. The evidence suggests that the pupal diapause of Cecropia results from the failure of the brain as a whole. The diapausing brain is electrically silent, apparently because of the absence of ChE. During diapause there is an accumulation of a cholinergic substance in the brain—an observation which suggests that the reappearance of ChE is elicited by high substrate concentrations. When ChE reappears, the brain becomes electrically active, the neurosecretory cells release brain hormone, and diapause is ended.

ENVIRONMENTAL MODIFICATION OF CERTAIN ENDOCRINE PHENOMENA1

IT HAS long been known that certain endocrine readjustments may be caused by exteroceptive stimuli. Examples may be found in many of the endocrine glands.The yearly growth and regression of the sexual organs in animals in which reproduction is seasonal are closely correlated with the external temperature and light conditions (1, 2). The act of mating, as well as mechanical stimulation of erogenous zones,is necessary for the induction of ovulation in the rabbit and pseudopregnancy in therat. Exposure to cold causes an increase in the basal metabolic rate, in the thyroidcell height, and in the weight of the adrenal cortex. Conversely, maintenance in a hotenvironment has been observed to lower the metabolic rate (3). These observationsall support the generalization that important changes in endocrine activity can result from changes in the external world. Such observations have prompted a re examination of the endocrine responses toseveral environmental stimuli.