Šio darbo tiklas buvo nustatyti senų arklių sveikatos palaikymui naudojamų gliukokortikoidų poveikį kraujo biocheminiams rodikliams ir įvertinti kaip pasikeičia kraujo gliukozės, bendrųjų baltymų ir trigliceridų koncentracija kraujyje panaudojus ilgo ir trumpo veikimo gliukokortikoidų dozės. Tyrimams buvo atrinkta 18 senų sportinių veislinių žirgų, kurie anksčiau intensyviai buvo naudojami sportinėje veikloje. Visi jie eržilai, turintys negalavimų susijusių su senomis sąnarių ir nugaros traumomis. Sudarytos trys žirgų grupės. I gr. žirgams buvo taikomas palaikomasis gydymas naudojat trumpo veikimo gliukokortikoidų preparatą po 2,0 ml / 100 kg svorio. Organizme preparatas išlieka iki 24 val. II gr. žirgams buvo naudojamas ilgai veikiantis gliukokortikoidų preparatas po 10,0 ml neatsižvelgiant į arklio svorį. III gr. – kontrolinė. I ir II grupių žirgų kraujas buvo imamas 6 kartus, o kontrolinės – vieną kartą. Prieš preparato suleidimą ir po suleidimo praėjus 1, 2, 3, 4 ir 7 d. ir nustatoma gliukozės, bendrųjų baltymų ir trigliceridų koncentracija. Tyrimo metu nustatyta, kad naudojant preparatus ilgo ir trumpo veikimo su gliukokortikoidais, pakinta medžiagų apykaita ir padidėja gliukozės, trigliceridų ir bendrųjų baltymų koncentracija kraujyje. / Aim of the study: The aim of this study was to establish, how the results of old horses biochemistry blood tests, such as glucose, total proteins and triglycerides change after the use of long acting or short acting glucocorticoids. Methods: There were 18 old sport horses in this study. All of them were stallions, who had old joint and back traumas. The horses were divided into the three groups: horses from the first group were treated with the short acting glucocorticoids – 2,0 ml / 100 kg. It remains in the body for up to 24 hours. Horses from the second group were treated with long acting glucocorticoids – 10,0 ml. It remains in the body for up to 4 days. The third was control group of horses. Blood samples from the horses of the first and second group were taken 6 times. Blood samples from the control group were taken once. Before the injection and after the injection of glucocorticoids, the concentration of glucose, total protein and triglycerides were carried out. Results: The test results showed, that the use of long and short acting glucocorticoids can change the metabolism. After the use of glucocorticoids, the concentration of glucose, triglycerides and total proteins have increased.

Aerozolinė terapija, lėtine obstrukcine plaučių liga sergantiems arkliams, nėra labai dažnai taikomas gydymo būdas Lietuvoje, tačiau ši terapija yra plačiai taikoma kitose šalyse. Aerozolinė terapija yra efektyvus arklių lėtinės obstrukcinės plaučių ligos gydymo būdas. Darbo tikslas: Šio darbo tikslas yra nustatyti bronchus plečiančių preparatų, kaip salbutamolio ir gliukokortikoidų preparatų, kaip deksametazono, aerozolinės terapijos įtaką, lėtine obstrukcine plaučių liga sergančių arklių kraujo dujoms ir kraujo ląstelių morfologijai. Metodai: Tyrimui buvo atrinkti šeši arkliai, kurių amžius yra nuo 5 iki 18 metų. Visi arkliai buvo laikomi vienodomis sąlygomis. Arkliai buvo suskirstyti į dvi grupes: į pirmąją grupę buvo atrinkti trys arkliai (n=3), su klinikiniais lėtinės obstrukcinės plaučių ligos simptomais. Visiems pirmojoje grupėje esantiems arkliams anksčiau buvo diagnozuota lėtinė obstrukcinė plaučių liga. Į kontrolinę grupę buvo atrinkti trys sveiki arkliai (n=3), kuriems niekada nebuvo pasireiškusios kvėpavimo takų ligos. Aerozolinė terapija buvo taikoma vieną kartą per dieną, septynias dienas iš eilės. Pirmiausia buvo inhaliuojamas salbutamolis, o tada - deksametazonas. Kontrolinės grupės arkliai nebuvo gydomi. Kraujo tyrimai pirmosios grupės arkliams buvo imami prieš taikant aerozolinę terapiją ir po septynių dienų aerozolinės terapijos taikymo. Antrosios grupės arkliams kraujo tyrimai buvo imami vieną kartą. Kraujo dujų tyrimas buvo atliekamas iš karto po... [toliau žr. visą tekstą] / Equine aerosol therapy for treating recurrent airway disease in horses is not a very common therapy used in Lithuania, but it is widely used in other countries. It is a very effective way of treating horses in crisis with reccurent airway disease. Aim of the study: The aim of this study was to establish, how the results of blood gas and blood cell morphology change after an aerosol bronchodilator such as salbutamol and the use of glucocorticoid such as dexamethazone for therapy on horses with recurrent airway disease. Methods: There were six horses in this study, 5 - 18 years of age, and they were kept under the same conditions. The horses were divided into two groups: the first group was made up of three horses (n = 3), previously diagnosed with recurrent airway disease. At the time of the study they had clinical signs of the disease. The control group were also made up of three horses (n = 3), who have never been diagnosed with respiratory diseases. Horses from the first group, were treated with aerosol salbutamol and dexamethasone for a week, once a day, with an ultrasound nebulizer. Horses from the control group were not treated. Blood samples from the horses of the first group were taken before aerosol therapy and after a one week period of therapy blood samples were drawn again for comparison. Blood samples from the control group were taken once. Blood gas tests were carried out with an Epoc blood analyzer and blood cell morphology was carried out with Abacus... [to full text]

Mountain caribou (Rangifer tarandus caribou) are endangered in British Columbia and motorized backcountry recreation has been identified as a potential threat to their persistence. My objective was to test if fecal glucocorticoids (GCs), indicative of physiological effects of ecological stress in wildlife, could be used as a non-invasive tool to quantify stress response in free-ranging caribou exposed to motorized recreation. I validated an enzyme-linked immunosorbent assay (ELISA) to measure concentration of fecal GCs for R. tarandus using an adrenocorticotropic hormone (ACTH) challenge experiment on captive reindeer exposed to extreme variation in winter weather. Female reindeer expressed elevated fecal GCs 9-11 hrs after ACTH injection. Males showed no detectable increase, perhaps due to underdosing. Fecal GCs varied markedly in both sexes in response to natural variation in weather. Overall, my results indicated fecal assays can be used to track biologically meaningful changes in adrenal activity in R.tarandus. I investigated the effects of motorized recreation on stress hormone production by measuring GCs in feces of mountain caribou exposed to snowmobile and heli-ski activity. Concentrations of fecal GCs in snowmobile and heli-ski areas were higher than those measured from caribou in areas where motorized recreation was not allowed. Caribou sampled up to 4km. 8km and I0 km distant from snowmobile activity showed elevated fecal GCs when compared to those sampled further from snowmobile activity areas. Other variables with a significant effect on fecal GCs included reproductive state, snow, aspect. minimum ambient temperature, and daily temperature range. My study indicates that measurement of fecal GCs provides a useful, noninvasive approach in the evaluation of physiological effects of environment, reproductive state, and human-induced stressors on free-ranging mountain caribou. Although research on many species indicates that chronically elevated GCs carry a variety of physiological costs, more study is needed to know whether GCs can be used as an index of human impact on population health or trend.

Glucocorticoids are widely used in clinical therapy. However, they cause adverse effects including insulin resistance and Type 2 diabetes, which are characterised by decreased glucose transport into the muscles and fat. How glucocorticoids inhibit glucose transport remains unclear. Insulin stimulates glucose uptake via the insulin receptor substrate (IRS)-1 / phosphoinositide-3-kinase (PI3K) / protein kinase B (AKT) pathway and promotes the redistribution of GLUT4 from intracellular storage compartments to the plasma membrane (PM). Insulin-stimulated phosphorylation of AKT substrate of 160 kDa (AS160), a Rab-GTPase activating protein is downstream of AKT and appears to be essential for exposure of GLUT4 at the PM and glucose uptake. This is mediated through the association of phosphorylated AS160 (at the key residue T642) with 14-3-3 in the cytosol. The mildly insulin-responsive GLUT1 mediates basal glucose uptake in adipocytes. It is also subject to regulated trafficking like GLUT4. This study aimed to determine the level at which glucocorticoids inhibit glucose uptake in adipocytes. Effects of the synthetic glucocorticoid dexamethasone (Dex) and the natural glucocorticoid cortisol, on GLUT1 and GLUT4 function were examined. Candidates for the glucocorticoid-mediated inhibition of GLUT1- and GLUT4-mediated glucose uptake were investigated. These were glycogen synthase kinase (GSK) 3β (an AKT substrate) for GLUT1-mediated glucose transport; and adaptor protein containing PH domain, PTB domain, and leucine zipper motif (APPL)-1 (an AKT-interacting protein) and AS160 for GLUT4-mediated glucose transport. Dex and cortisol significantly decreased basal glucose uptake by 50% (p<0.05) in SGBS and 3T3-L1 adipocytes. Similarly, insulin-stimulated glucose uptake was decreased by 50% (p<0.001 for SGBS; p<0.05 for 3T3-L1) and 30% (p<0.05 for both) at 1 nM and 100 nM insulin respectively. Similar results were observed with differentiated primary human preadipocytes and human adipose explants. Dex-mediated inhibition of basal glucose uptake was limited to insulin-sensitive cell types implying that glucocorticoids may regulate GLUTs at steps common to GLUT1 and GLUT4 trafficking. Dex-mediated reduction in glucose uptake correlated with the reduction in basal and insulin-stimulated expression of GLUT1 and GLUT4 to the PM without changes in total GLUT1/4 expression. Dex did not alter total expression or phosphorylation of proximal insulin-signalling molecules up to and including AKT but increased FOXO1 expression, and modified GSK3β-S9 phosphorylation. Dex did not alter total APPL1 expression or subcellular distribution. Dex significantly decreased 1nM-insulin stimulated AS160-T642 phosphorylation by 50% (p<0.05) in SGBS and 3T3-L1 adipocytes via the glucocorticoid repector (GR). This correlated with reduced AS160:14-3-3 interaction. Similar results were obtained for AS160-T642 basal phosphorylation. At 1nM insulin, AS160-T642 phosphorylation is maximal at sub-maximal glucose uptake, i.e. AS160 phosphorylation significantly contributes to glucose uptake. RU486 significantly prevented but did not fully abrogate the Dex-mediated reduction in glucose uptake suggesting additional Dex-induced defects. In conclusion, glucocorticoids inhibit glucose uptake at a level distal to AKT by GR-dependent mechanisms. A role for GSK3β or APPL1 in glucocorticoid-mediated inhibition of glucose uptake requires further investigations. FOXO1 represents a suitable candidate for mediating the Dex-induced defects. Of significance, perturbation in AS160-T642 phosphorylation contributes to Dex-mediated inhibition of glucose uptake. Thus, AS160 presents a novel therapeutic target in the improvement of glucocorticoid-mediated inhibition of glucose uptake.

Protein wasting is a complication of glucocorticoid (GC) therapy. It causes substantial morbidity and there is no treatment. This thesis investigates the metabolic mechanisms underlying GC-induced protein wasting and the potential for anabolic hormones to reverse protein loss. The models of GC excess were Cushing's syndrome and GC therapy. Whole body protein metabolism was assessed using the leucine turnover technique and body composition by dual-energy X-ray absorptiometry to estimate lean body mass (LBM) and fat mass (FM). As previous studies demonstrated that LBM and FM influenced rates of protein metabolism, the magnitude of body compositional abnormality in Cushing's syndrome was determined. After accounting for the greater FM (30%) and lesser LBM (15%), protein metabolism in Cushing's syndrome was characterised by a significant increase in protein oxidation, an abnormality that leads to irreversible protein loss. Successful treatment of Cushing's syndrome normalised protein oxidation. Studies of the acute and chronic effects of therapeutic GCs revealed a time-dependent effect on protein metabolism. GCs acutely increased protein oxidation. However, the rate of protein oxidation during chronic therapy at a similar dose was not significantly different to untreated control subjects. This time-dependent change suggests that GC-induced stimulation of protein oxidation does not persist and could represent a metabolic adaptation to limit protein loss. This finding contrasts with that in Cushing's syndrome, where protein oxidation is persistently elevated. This difference may represent a dose effect. Studies in GH-deficient subjects revealed that GH induced a fall in protein oxidation that was significantly correlated with a subsequent gain in LBM. This suggests that the anabolic potential of a therapeutic substance can be predicted by its ability to suppress protein oxidation acutely. Finally, the potential for GH and androgens to reverse the metabolic effects of GCs was assessed. A preliminary study in GC users revealed that a GH dose of 0.8 mg/d was effective in reducing protein oxidation. In a subsequent study, the GH-induced reduction in protein oxidation in women on GCs was enhanced by combined treatment with dehydroepiandrosterone, an androgen. In summary, GCs induce protein loss by stimulating protein oxidation. GH reverses this effect and this action is enhanced by coadministration of androgens. GH and androgens may be used therapeutically to prevent protein loss induced by GCs.

Asthma is a chronic inflammatory disease of the airways. Using a murine model which replicates many characteristic features of human asthma, this study evaluated the effects of treatment with anti-inflammatory drugs on the lesions of chronic asthma, and investigated potential underlying molecular mechanisms. Treatment with dexamethasone, a glucocorticoid, was compared with roflumilast, a novel phosphodiesterase-4 (PDE4) inhibitor. BALB/c mice sensitised to ovalbumin were challenged with a low mass concentration of aerosolised antigen for 30 min/day, 3 days/week for 6 weeks. In weeks 5 and 6, groups of animals were treated with either dexamethasone or roflumilast. Assessment included changes in acute-on-chronic inflammation, structural remodelling of the airways and airway hyper-responsiveness to a bronchoconstrictor stimulus. These were correlated with the expression of pro-inflammatory cytokines and growth factors. Compared to vehicle-treated control animals, dexamethasone- and roflumilast-treated mice exhibited reduced accumulation of intra-epithelial eosinophils and chronic inflammatory cells, including CD3+ T-lymphocytes in the airways. Similarly, both drugs inhibited subepithelial fibrosis and airway epithelial thickening, although only dexamethasone inhibited goblet cell hyperplasia/metaplasia. Airway hyper-reactivity was not diminished by either drug. Both treatments suppressed production of Th2 cytokines by ovalbumin-restimulated peribronchial lymph node cells. In selectively dissected airway tissue from vehicletreated animals, increased expression of mRNA for several pro-inflammatory cytokines (TNF-α, GM-CSF, IL-6) and cytokines characteristic of Th1 (IFN-γ), Th2 (IL-5, IL-13)and Th17 (IL-17A) cells was demonstrated using real-time PCR. Enhanced expression of growth factors (TGF-β1 and FGF-2) was also demonstrated in airway epithelium isolated by laser capture microdissection. Interestingly, whereas treatment with dexamethasone significantly inhibited expression of mRNA for all of the inflammationrelated cytokines examined, roflumilast inhibited only IL-17A, TNF-α, GM-CSF and IL-6. Both drugs inhibited mRNA expression of growth factors by epithelial cells. Because roflumilast was as effective as dexamethasone in suppressing inflammation and most changes of remodelling, the selective suppression of IL-17A, TNF-α, GM-CSF and IL-6 suggests that these mediators, or the cells that produce them, may have critical roles in pathogenesis. Furthermore, they may be particularly appropriate therapeutic targets in chronic asthma.

[Truncated abstract] In obstetric practice, pregnant women at risk of pre-term delivery between 24 and 34 weeks of gestation are administered synthetic glucocorticoids (betamethasone or dexamethasone) to induce fetal organ maturation. During this gestational period, the fetal kidney is undergoing a phase of rapid organogenesis with an increase in renal growth and active nephrogenesis occurring. The studies comprising this thesis examine the effects of prenatal betamethasone exposure on the fetal and adult ovine kidney. The central hypothesis of these studies was that exposure of the fetal kidney to betamethasone in late gestation would change renal structure and induce long-term alterations in the expression of glucocorticoid-sensitive genes and proteins. In the fetal studies, pregnant Merino ewes bearing single fetuses received single or repeated-weekly intra-muscular (i.m.) injections of betamethasone (0.5 mg/kg body weight) or saline commencing on day 104 of gestation (term is 150 days). Kidneys were collected from fetuses at 109, 116, 121 and 146 days of gestation (d). Using gold standard unbiased stereological techniques, the physical disector/fractionator method, total glomerular (nephron) number and glomerular volume were determined in 146 d fetal kidneys exposed to repeated maternal saline or betamethasone administration. In the adult study, kidneys were collected from 3.5-year-old sheep that had been exposed to ... In this thesis I have demonstrated that renal growth restriction as a result of betamethasone exposure is associated with a reduction in fetal nephron endowment. Although betamethasone does not appear to consistently alter nephron number or glomerular size, it may indirectly affect total nephron endowment through effects on renal growth. I have also provided evidence which suggests that lategestation betamethasone exposure in sheep does not program permanent alterations in the renal expression of genes or proteins involved in glucocorticoid hormone action or components of the renin-angiotensin system. Therefore, exposure of the fetal kidney to betamethasone during nephrogenesis may alter renal structure if kidney growth is perturbed; however, there are no persistent alterations in the expression of glucocorticoid-sensitive genes. These findings are consistent with the preservation of normal basal blood pressure in the adult sheep I studied and with the limited results from human studies of late-gestation maternal glucocorticoid administration.

[Truncated abstract] Increased incidence of hypertension, insulin resistance, obesity and dyslipidemia, collectively referred to as the metabolic syndrome, has been linked to low birth weight, an indicator of a poor fetal environment. This association reflects developmental programming, a process by which organ systems are affected during early development such that disease states are more likely to emerge in adult life. Fetal glucocorticoid overexposure is thought to be a key factor that mediates developmental programming. Accordingly, maternal treatment with the synthetic glucocorticoid dexamethasone retards fetal growth and leads to delayed puberty, hypertension, hyperinsulinemia, and hyperleptinemia, either with or without increased adiposity, in adult offspring. Importantly, the postnatal environment can either amplify or attenuate the long-term outcome of developmental programming. The focus of this thesis was whether adverse developmental programming outcomes can be attenuated by the postnatal environment and thus provide therapeutic potential. Specifically, the effects of a postnatal diet rich in omega-3 fatty acids on glucocorticoid-induced developmental programming outcomes was investigated. ... The adipocyte phenotype was examined in Study 6, with hyperleptinaemia evident in offspring at 6 and 12 months of age in dexamethasone-exposed animals on a standard omega-3 diet, but this effect was prevented by a high omega-3 diet. The pattern of plasma leptin was paralleled by changes in leptin mRNA in retroperitoneal fat. Similarly, plasma levels of the inflammatory markers IL-6 and IL-1β were upregulated by prenatal glucocorticoid exposure and these were attenuated by postnatal dietary omega-3 fatty acids. Overall, omega-3 ingestion reduced adiposity, as indicated by measures of body composition. In conclusion, the studies presented in this thesis demonstrate for the first time that many of the detrimental effects of excess glucocorticoid exposure in utero on the adult phenotype can be attenuated by a postnatal diet rich in omega-3 fatty acids. This beneficial effect of omega-3 fatty acids was associated with a reversal of some (e.g. adiposal leptin) but not all (e.g. renal GR) 'programmed' changes in gene expression. These findings raise the possibility that dietary supplementation with omega-3 fatty acids may provide a viable therapeutic option for preventing and/or reducing adverse programming outcomes in humans.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Dissertation (PhD)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.