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Thesis (Ph. D.)--University of Virginia, 2006. / Bracketed B in title is the Greek letter beta. Includes bibliographical references (leaves150-169). Also available online through Digital Dissertations.

A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg / Throughout the world, many traditional plant treatments for diabetes exist and therein lies a hidden wealth of potentially useful natural products for diabetes contrl. Despite this, few traditional antidiabetic plants have received scientific or medical scrutiny, and the World Health Organisation ( 1980 ) recommended accordingly that this area warrants further evaluation. / IT2018

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning)--Umeå : Umeå universitet, 2009. / Härtill 3 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 3 uppsatser.

Orientadores: Antonio Carlos Boschiero, Alex Rafacho / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T03:03:43Z (GMT). No. of bitstreams: 1 Protzek_AndreOtavioPeres_D.pdf: 8312725 bytes, checksum: 2126056342598338000e5d9925e59082 (MD5) Previous issue date: 2013 / Resumo: Os glicocorticoides (GC) são amplamente utilizados devido aos seus efeitos anti-inflamatórios. Porém, o tratamento com GC pode induzir efeitos deletérios sobre a homeostase glicêmica como a resistência à insulina (RI), intolerância à glicose e, dependendo do tempo e dose, pode levar a instalação do Diabetes mellitus tipo 2 (DM2). Neste sentido, ratos têm sido vastamente utilizados como modelo animal para elucidar as compensações pancreáticas envolvidas na hiperinsulinemia induzida por GC e, poucos estudos enfocando os efeitos do tratamento com GC foram realizados em camundongos. Além disso, não é completamente elucidado se a hiperinsulinemia compensatória induzida pelo tratamento com GC esta associada com alteração do clearance de insulina. Assim, nossos objetivos foram avaliar se: as compensações do pâncreas endócrino em resposta ao tratamento com GC são similares entre camundongos e ratos e, identificar possíveis mecanismos que as expliquem; e se a hiperinsulinemia compensatória induzida pelo tratamento com GC em camundongos e ratos esta associada com alterações do clearance de insulina e a expressão da proteína insuling degrading enzyme (IDE) no fígado. Para isto, camundongos Swiss e ratos Wistar machos foram tratados com o glicocorticoide sintético dexametasona (1 mg/kg p.c.; 5 dias consecutivos). O tratamento com GC induziu RI, hiperinsulinemia e dislipidemia em ambas as espécies, embora mais pronunciado em ratos, que também apresentaram intolerância à glicose e hiperglicemia no jejum. Ambas as espécies tratadas com GC apresentaram incremento da secreção de insulina ex vivo estimulada com glicose, massa e proliferação de células ?, que foram associados com aumento da sinalização da via Ir-?/AKT/mTOR e redução da via AMPK/ACC/AS160 em ilhotas isoladas. O clearance de insulina reduziu em camundongos e ratos tratados com GC, o que foi associado com redução da expressão de IDE no fígado. Desta forma, nossos resultados indicam que camundongos são menos sensíveis aos efeitos deletérios do tratamento com GC sobre a homeostase glicêmica, quando comparado com ratos. Ainda, camundongos e ratos apresentam compensações pancreáticas semelhantes (incremento da função e massa de células ?) em resposta ao tratamento com GC, que foi associado com aumento da sinalização da via canônica de insulina e redução da via não canônica em ilhotas isoladas. Além disso, a redução do clearance de insulina foi, ao menos em parte, devido a redução da expressão de IDE no fígado, o que contribuiu para a hiperinsulinemia compensatória em ambas as espécies tratadas com GC. Em conclusão, estes resultados corroboram a hipótese de que fármacos que inibam a expressão ou atividade da IDE no fígado podem ser uma intervenção anti-diabetogênica que auxilie na manutenção da homeostase glicêmica sem sobrecarregar as células ? / Abstract: Glucocorticoids (GCs) are widely used as anti-inflammatory agent, but they may induce adverse metabolic effects such as insulin resistance (IR), glucose intolerance, and occasionally, diabetes mellitus type 2. Healthy rats have been used as animal models to elucidate the islet compensatory mechanisms involved in these metabolic disturbances, and only a few studies, which have focused on the in vivo effects of GCs, have been conducted in mice models. Yet, whether the reduced insulin clearance also contributes to the compensatory hyperinsulinemia in GC-treated rodents is not fully understood. Here, we aimed to elucidate whether mice and rats share the pancreatic compensations that result in response to dexamethasone (DEX) treatment and also to identify the possible mechanisms that can explain its effects. Yet, we investigated whether the hyperinsulinemia induced by GC treatment in mice and rats is associated with altered hepatic insulin degrading enzyme (IDE) expression and insulin clearance. For this, male Swiss mice and Wistar rats were treated with the synthetic GC dexamethasone (1 mg/kg b.w.; 5 days). DEX treatment induced IR, hyperinsulinemia and dyslipidemia in both species (there was a higher magnitude in rats), but treatment had a greater effect in rats that had glucose intolerance and increased basal blood glucose compared to the control group. Ex vivo insulin secretion at different glucose concentrations was higher in both groups of DEX-treated rodents compared to their controls. Mice and rats showed a significant increase in ?-cell mass due to increased ?-cell proliferation, which was associated with upregulation of the Ir-?/AKT/mTOR and downregulation of AMPK/ACC/AS160 signaling. Insulin clearance reduced in GC-treated mice and rats, which were associated with reduced hepatic IDE expression. Thus, mice are less vulnerable than rats to the deleterious effect of GCs on glucose homeostasis. In addition, rats and mice share common islet compensations (increased ?-cell function and mass) in response to GC treatment, which were associated with increased canonical and decreased non-canonical insulin signaling. Farther, the reduced insulin clearance in GC-treated rodents was, at least in part, due to reduced hepatic IDE expression, which contributed to the compensatory hyperinsulinemia. These findings corroborate the idea that pharmacological interventions that inhibit hepatic IDE may be an alternative anti-diabetic agent that helps to maintain glucose homeostasis due to hyperinsulinemia instead of hypoglycemic agent, which increase the overload in the ?-cells and may lead to ?-cell failure and DM2 / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

A 69-year-old man was referred for elevated thyroid hormone levels. He had no symptoms apart from mild hyperhidrosis and heat intolerance with occasional headaches. Past medical history included a right hemithyroidectomy for a multinodular goiter and Hashimoto's disease. At presentation the patient had a firm, slightly enlarged left thyroid lobe. There were no visual abnormalities, and the rest of the physical findings were unremarkable. Laboratory findings included elevated values of free T4, free T3, total T 3, thyrotropin-secreting hormone (TSH), antithyroglobulin, and antimicrosomal antibodies. Normal values were found for cortisol, prolactin, testosterone, follicle-stimulating hormone, luteinizing hormone, a-subunit, and thyroid-stimulating immunoglobulin. Thyroid 123I scan showed an increased 5-hour uptake of 23% and a 24-hour uptake of 53% with a diffuse uniform enlargement of the left side. TSH level did not increase after a thyrotropin-releasing hormone stimulation test. Serum sex hormone binding globulin was elevated. Magnetic resonance imaging of the pituitary revealed a pituitary macroadenoma with suprasellar extension to the optic chiasm. Histologic examination of the adenoma after transsphenoidal hypophysectomy showed cells that stained positive for TSH. TSH-secreting pituitary adenomas account for 1% of functioning pituitary tumors and are an exceedingly rare cause of hyperthyroidism. To our knowledge, this is the first report of pituitary tumor inducing hyperthyroidism in the setting of Hashimoto's disease. There is a possibility that TSH elevation related to Hashimoto's disease might have contributed to the development of a TSH-secreting pituitary adenoma.