Adrenal gland, as an important effector tissue of the sympathetic nervous system, has critical roles in cardiovascular system under both chronic hypoxia (CH) and intermittent hypoxia (IH) conditions. Nitric oxide (NO), synthesized by nitric oxide synthases (NOS), is the most important intracellular signaling molecule, as well as free radical in response to hypoxia. Yet the regulation and effects of endogenous NO production mediated in the adrenal medulla induced by hypoxia remains largely unknown. We first studied how endogenous NO production were regulated by different NOS in rat adrenal medulla in response to CH or IH. After CH, elevated levels of endogenous NO production, eNOS expression, and apoptotic chromaffin cells were observed in the adrenal medulla. However, a remarkable decreased endogenous NO production and nNOS expression were shown in the IH-treated adrenal medulla. These results suggested that, in the rat adrenal medulla, the elevation of NO production through increased protein level of eNOS may play a protective role in the adaptive response to CH; the reduction of NO production through decreased expression of nNOS is important for the pathophysiological response to IH. The oxidative stress and cellular injury in the adrenal medulla under chronic intermittent hypoxia (CIH) condition is undefined. We tested the hypothesis that melatonin, a potent antioxidant, is protective against CIH-induced oxidative stress and local inflammation in the rat adrenal medulla. Results showed that levels of oxidative stress, lipid peroxidation, and inflammatory mediators were significantly increased after CIH treatment. Also, the protein levels of antioxidant enzymes were significantly lowered in the hypoxic group. Co-treatment of melatonin with hypoxia significantly reduced oxidative stress and inflammatory responses in the adrenal medulla. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. Thus, melatonin may act as a protective agent against adrenal damages in patients with severe obstructive sleep apnea syndrome. Previous studies have shown that CIH associated with recurrent apnea induced oxidative stress and pathophysiological changes in the cardiovascular system. Yet the mechanism of the CIH-induced oxidative stress and local inflammation in the adrenal medulla was undefined. We therefore determined whether the up-regulation of the expression of NADPH oxidase (NOX) mediated by renin-angiotensin system (RAS) may take part in the injuries caused by CIH in the rat adrenal medulla. We found that CIH treatment dramatically induced marker levels of adrenal oxidative stress, inflammation, macrophage infiltration, and apoptosis in rats. Co-treatment with NOX inhibitor, apocynin, counteracted such reactions. Furthermore, the mRNA levels of NOX subunits (p22PHOX, NOX2, and NOX4) and RAS components (ATG, AT1, and AT2) were increased significantly in the CIH group, but reduced in apocynin-treated CIH group, supporting the involvement of NOX and RAS in CIH-induced adrenal injury. In conclusion, we defined the roles of NO production, NOX, and RAS in the rat adrenal injury during hypoxic conditions. We also found that melatonin can protect adrenal medulla from hypoxia-induced damages in rat. / published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

Multiple endocrine neoplasia syndrome type 1 (MEN1) is an autosomal dominantly inherited disease, which is described as an association of tumors mainly in endocrine organs, including pancreas and adrenal glands. Pancreatic neuroendocrine tumors (PNETs) are the most common cause of death in MEN1 patients. More than one third of the MEN1 patients also develop enlargement of the adrenals. MEN1 is caused by a germline mutation of MEN1 gene, a tumor suppressor gene that is located on the human chromosome 11. As noticed, the MEN1 related tumors often develop prior to inactivation of both wild type alleles, indicating MEN1 haploinsufficiency. In this thesis, I utilized a conventional Men1 mouse model that has the phenotype mimicking the human MEN 1 traits, in order to investigate MEN1 tumorigenesis in endocrine pancreas and adrenal glands.   The microvascular aberrations contributing to development and maintenance of PNETs were characterized. The increased vascular density of PNETs developed in the Men1 mice was paralleled by an early and extensive redistribution of pericytes within endocrine tissue. These morphological alterations were supported by fine-tuned variations in expression of several angiogenic regulators  (VEGF, FGF and PDGF) and were further potentiated by hypoxia. Vascular reactivity and blood perfusion of tumor arterioles were significantly altered in response to glucose and L-nitro-arginine methyl ester. Investigation of adrenals from10-month-old Men1 mice showed 681 proteins in mass spectrometry data sets, in which 52 proteins were commonly found in the Men1+/+ and Men1+/- adrenals, and the differential expression between the genotypes reached significant levels. Prdx3, catalyzing the reduction of oxidative stress to cell survival, is one of the overexpressed proteins. Some proteins belonging to the PPARα pathway, e.g. ACLY were also overexpressed. Subsequent microRNA (miRNA) profiling analysis of adrenals from the same age group revealed 31 miRNAs whose expression was significantly altered in comparison between the genotypes. The tumor suppressor miRNAs, miR-486, miR-330 and miR-214, were significantly downregulated in Men1+/- adrenals. The latter, miR-214, is known to inhibit ACLY expression. This finding was in concordance with the proteomic analysis. The oncogene miRNAs, miR-132 and miR-494, were significantly enhanced in the Men1+/- adrenals. Gene ontology analysis demonstrated overrepresentation of the miRNA-targeted genes that are involved in nucleic acid metabolism, vasculature development, angiogenesis, and transcription. Together, these finding after validation in humans may be exploited to improve MEN1 cancer treatment.

Thesis (M.Sc.)--University of Adelaide, 1952. / "November 1951." Includes bibliographical references.

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Radyodiagnostik Anabilim Dalı, 2003. / Bibliyografya var.

Thesis (Ph. D.)--University of Virginia, 1997. / Spine title: c-Src-Associated PTPase. Includes bibliographical references (169-197). Also available online through Digital Dissertations.

The multiple functions of the pineal gland have been collectively interpreted as constituting a general anti-stressogenic role. The adrenal glands play a central role in maintaining homeostasis. The major neuroendocrine consequence of long-term stress is elevated circulating glucocorticoid levels. In this study, the effect of chronic, oral hydrocortisone treatment on pineal biochemistry was investigated in male Wi star rats of the albino strain. The results show that seven days of oral hydrocortisone treatment endows the pineal gland with the ability to increase melatonin synthesis in organ culture. The increase is accompanied by a rise in NAT activity, cyclic AMP levels and enhanced specific binding to the pineal B-adrenergic receptors. It appears that hydrocortisone sensitizes the pineal gland to stimulation by B-adrenergic agonists. thus rendering the pineal more responsive to B-adrenergic agonists. Further studies were directed at demonstrating an anti-stressogenic function for the pineal gland by investigating whether the principal pineal indole, melatonin. could protect against the deleterious effects of elevated. circulating drocortisone levels. The results show that chronic, oral hydrocortisone treatment significantly increases liver tryptophan pyrrolase activity. The catabolism of tryptophan by tryptophan pyrrolase is an important determinant of tryptophan availability to the brain, and therefore, brain serotonin levels. The findings show that melatonin inhibits basal and hydrocortisone-stimulated liver tryptophan pyrrolase apoenzyme activity in a dose-dependent manner. This inhibition suggests that melatonin may protect against excessive loss of tryptophan from circulation and against deficiencies in the cerebral serotinergic system which are associated with mood and behavioural disorders. It was shown that another deleterious effect of chronic hydrocortisone treatment is a significant increase in the number of glutamate receptors in the forebrain of male Wistar rats. The increase in receptor number observed in this study is probably due to an increase in the synthesis of glutamate receptors and is associated with a marked reduction in the affinity of the glutamate receptors for glutamate. possible to demonstrate an receptor number or the For practical reasons, it was not effect of melatonin on either glutamate affinity of glutamate receptors for glutamate in rat forebrain membranes. In view of the neurotoxic effect of glutamate in the eNS, the functional significance of recently described glutamate receptors in the pineal gland was investigated. The results show that 10-4 M glutamate significantly inhibits the isoprenaline-stimulated synthesis of N-acetylserotonin and melatonin in organ culture when the pineal glands were pre-incubated with glutamate for 4 hours prior to stimulation with isoprenalin and when glutamate and isoprenaline were administered together in vitro. GABA, a glutamate metabolite could not mimic the decrease in isoprenalinestimulated melatonin, and it is likely that the observed effects were directly attributed to glutamate. Incubation of the pineal gland with 10-4 M glutamate in organ culture did not affect HIOMT activity in pineal homogenates, but significantly elevated both basal and isoprenaline-stimulated NAT activity. It was concluded that glutamate only inhibits melatonin synthesis in intact pineal glands and not in pineal homogenates. The present study has provided further support for an interaction between the pineal and the adrenal glands. There is an ever increasing likelihood that melatonin is an anti-stressogenic hormone and that the pineal gland may have a protective role to play in the pathology of stress-related diseases.

Due to the large volume and often conflicting results reported on postoperative endocrinological changes, the practicing surgeon has difficulty in finding applicable principles. A knowledge of these principles is however necessary for an understanding of the mechanisms responsible for survival of the organism after surgery. The results thus far thus far reported are based upon complicated methodology, and may appear to be more theoretical than of practical value. Studies based upon small laboratory animals are indeed statistically significant, but the interpretation of these results as applied to the patient is difficult. Controlled human studies have been few in number and only very small areas of the total picture have been studied. There are a few studies on surgical patients; however, the variable results make the conclusion questionable. Nevertheless, these studies have lent a realistic significance to the evaluation of the total postoperative state.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Massas adrenais clinicamente silenciosas, diagnosticadas ao acaso ("incidentalomas"), são frequentemente encontradas em avaliações radiológicas devido ao constante progresso dos métodos de imagem. Na revisão das principais fontes científicas até 2004, analisado o grau de evidência concluiu-se: a maioria dos "incidentalomas" são não hipersecretores, mas a avaliação endócrina demonstrou que é comum o achado de hiperfunção hormonal discreto; "incidentaloma" acima de 6cm sugerem malignidade e entre 4-6cm devem ser analisadas por suas características de imagem; adrenalectomia deve ser indicada em massas adrenais funcionantes; massas adrenais não operadas devem ser acompanhadas pelo prazo de 2 anos / Introduction: Clinically silent adrenal masses, incidentally diagnosed during imaging methods performed for other clinical conditions (“incidentalomas") have been more frequently detected due to the constant improvement in imaging methods. There are several causes, diagnoses and treatments for these masses. Thus, whenever a physician comes across such lesion, it is necessary to define whether this mass is hormonally active and whether there is a risk of being malignant. Nevertheless, the methods for clarifying these issues have yet to be defined. Objective: To evaluate the best diagnosis, treatment and follow up of the incidental adrenal lesion. Methods: The main scientific literature available until October 2004 was reviewed, taking evidence into account. Results: Two studies which selected and reviewed articles until September 2003 were found. Fourty-three other studies included in a systematic review until October 2004 were added to this study. Conclusions: In general, “incidentalomas" are non-functioning, but endocrinological evaluation has shown that subclinical hormonal hyperfunction is not unusual, thus stressing the need for measuring substances such as with metanephrine assay, dexamethasone suppression test in low dosage and establishing the upright plasma aldosterone/plasma renin activity ratio. Non-functioning “incidentalomas" smaller than 4 cm should be followed carefully; those between 4 and 6 cm should be analyzed for its imaging characteristics; for those greater than 6 cm adrenalectomy is indicated. Functioning “incidentalomas" must undergo adrenalectomy. Nonoperated adrenal masses must be followed for two years through imaging and function testing.

Massas adrenais clinicamente silenciosas, diagnosticadas ao acaso ("incidentalomas"), são frequentemente encontradas em avaliações radiológicas devido ao constante progresso dos métodos de imagem. Na revisão das principais fontes científicas até 2004, analisado o grau de evidência concluiu-se: a maioria dos "incidentalomas" são não hipersecretores, mas a avaliação endócrina demonstrou que é comum o achado de hiperfunção hormonal discreto; "incidentaloma" acima de 6cm sugerem malignidade e entre 4-6cm devem ser analisadas por suas características de imagem; adrenalectomia deve ser indicada em massas adrenais funcionantes; massas adrenais não operadas devem ser acompanhadas pelo prazo de 2 anos / Introduction: Clinically silent adrenal masses, incidentally diagnosed during imaging methods performed for other clinical conditions (“incidentalomas”) have been more frequently detected due to the constant improvement in imaging methods. There are several causes, diagnoses and treatments for these masses. Thus, whenever a physician comes across such lesion, it is necessary to define whether this mass is hormonally active and whether there is a risk of being malignant. Nevertheless, the methods for clarifying these issues have yet to be defined. Objective: To evaluate the best diagnosis, treatment and follow up of the incidental adrenal lesion. Methods: The main scientific literature available until October 2004 was reviewed, taking evidence into account. Results: Two studies which selected and reviewed articles until September 2003 were found. Fourty-three other studies included in a systematic review until October 2004 were added to this study. Conclusions: In general, “incidentalomas” are non-functioning, but endocrinological evaluation has shown that subclinical hormonal hyperfunction is not unusual, thus stressing the need for measuring substances such as with metanephrine assay, dexamethasone suppression test in low dosage and establishing the upright plasma aldosterone/plasma renin activity ratio. Non-functioning “incidentalomas” smaller than 4 cm should be followed carefully; those between 4 and 6 cm should be analyzed for its imaging characteristics; for those greater than 6 cm adrenalectomy is indicated. Functioning “incidentalomas” must undergo adrenalectomy. Nonoperated adrenal masses must be followed for two years through imaging and function testing.