Publications by authors named "Ana Claudia Munhoz"

Obesity significantly decreases life expectancy and increases the incidence of age-related dysfunctions, including β-cell dysregulation leading to inadequate insulin secretion. Here, we show that diluted plasma from obese human donors acutely impairs β-cell integrity and insulin secretion relative to plasma from lean subjects. Similar results were observed with diluted sera from obese rats fed ad libitum, when compared to sera from lean, calorically restricted, animals.

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Article Synopsis
  • The study shows that melatonin plays a crucial role in maintaining pancreatic function and energy metabolism during pregnancy and early lactation in rats.
  • The absence of melatonin leads to impaired glucose metabolism and disrupted insulin secretion at various stages, affecting both pregnancy and lactation.
  • Melatonin's effects are likely related to MT2 receptors rather than its antioxidant properties, and proper melatonin levels can help restore pancreatic function and remodeling post-delivery.
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Fasting is known to cause physiological changes in the endocrine pancreas, including decreased insulin secretion and increased reactive oxygen species (ROS) production. However, there is no consensus about the long-term effects of intermittent fasting (IF), which can involve up to 24 hours of fasting interspersed with normal feeding days. In the present study, we analyzed the effects of alternate-day IF for 12 weeks in a developing and healthy organism.

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Purpose: Diabetes mellitus (DM) has a multifactorial etiology that imparts a particular challenge to effective pharmacotherapy. Thyroid hormone actions have demonstrated beneficial effects in diabetic as well as obese rats. In both conditions, inflammation status plays a crucial role in the development of insulin resistance.

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Context: Residual effects after nandrolone decanoate (ND) treatment are not reported.

Objective: Immediate and residual effects of low-dose ND and treadmill training were investigated.

Materials And Methods: Male rats were trained and/or ND-treated for four weeks and the assessments were made after this period or four weeks later.

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Melatonin is a hormone synthesized in the pineal gland, which modulates several functions within the organism, including the synchronization of glucose metabolism and glucose-stimulated insulin secretion (GSIS). Melatonin can mediate different signaling pathways in pancreatic islets through two membrane receptors and via antioxidant or pro-oxidant enzymes modulation. NADPH oxidase (NOX) is a pro-oxidant enzyme responsible for the production of the reactive oxygen specie (ROS) superoxide, generated from molecular oxygen.

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Mitochondria and NADPH oxidase are important sources of reactive oxygen species in particular the superoxide radical (ROS) in pancreatic islets. These molecules derived from molecular oxygen are involved in pancreatic β-cells signaling and control of insulin secretion. We examined the involvement of ROS produced through NADPH oxidase in the leucine- and/or glucose-induced insulin secretion by pancreatic islets from fed or 48-hour fasted rats.

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