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    Effects of glucagon as a neurohormone on the central nervous system and glucose homeostasis
    (Verduci Editore s.r.l, 2024) Tanbek, K.; Yilmaz, U.; Gul, S.; Koç, A.; Gul, M.; Sandal, S.
    OBJECTIVE: This study aimed to elucidate the possible effects of the acute/ long-term infusion of glucagon in the brain as the regulatory role on the endocrine secretions of the pancreas. MATERIALS AND METHODS: Ninety male Wistar albino rats were divided as Control, artificial Cerebrospinal Fluid (aCSF) (120 min), Glucagon (120 min), pancreatic denervation (PD)+aCSF (120 min), PD+Glucagon (120 min), aCSF (7 days), Glucagon (7 days), PD+aCSF (7 days) and PD+Glucagon (7 days). Glucagon and solvent (aCSF) were administered after pancreatic denervation (PD) by Hamilton syringe and osmotic mini pump (1 µg/10 µl/min) in the third ventricle of the brain. RESULTS: Acute intracerebroventricular (icv) administration of glucagon resulted in an elevation of glucagon levels and a concurrent reduction in blood glucose levels. Furthermore, in both the PD+aCSF (7 days) and PD+Glucagon (7 days) groups, there was a notable decrease in propiomelanocortin (POMC) and agouti-related protein (AgRP). Significant changes were observed in feed consumption and body weight, as well as pancreatic glucagon levels, with a simultaneous decrease in insulin levels in the PD (7 days), Glucagon (7 days), and PD+Glucagon (7 days) groups. These alterations were statistically significant when compared to the control group (p<0.05). CONCLUSIONS: The research outcomes established that pancreas-secreted glucagon functions as a neurohormone within the brain, activating central pathways linked to blood glucose regulation. The presence of glucagon led to a decrease in POMC levels. Surprisingly, this reduction in POMC resulted in the suppression of AgRP. Contrary to expectations, the suppression of AgRP led to an increase in food intake rather than a decrease. As already highlighted in the results section, it was emphasized that POMC may play a more significant role than AgRP in influencing feeding behavior. © 2024 Verduci Editore s.r.l. All rights reserved.
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    Neuroprotection against CCl4 induced brain damage with crocin in Wistar rats
    (Taylor & Francis Ltd, 2018) Altinoz, E.; Erdemli, M. E.; Gul, M.; Aksungur, Z.; Gul, S.; Bag, H. G.; Kaya, G. B.
    Owing to its lipophilic property, carbon tetrachloride (CCl4) is rapidly absorbed by both the liver and brain. We investigated the protective effects of crocin against brain damage caused by CCl4. Fifty rats were divided into five groups of ten: control, corn oil, crocin, CCl4 and CCl4 + crocin. CCl4 administration decreased glutathione (GSH) and total antioxidant status (TAS) levels, and catalase (CAT) activity, while significant increases were observed in malondialdehyde (MDA) and total oxidant status (TOS) levels and superoxide dismutase (SOD) activity. The cerebral cortex nuclear lamina developed a spongy appearance, neuronal degeneration was observed in the hippocampus, and heterochromatic and pyknotic neurons with increased cytoplasmic eosinophilia were observed in the hippocampus after CCl4 treatment. Because crocin exhibits strong antioxidant properties, crocin treatment increased GSH and TAS levels and CAT activities, and decreased MDA and TOS levels and SOD activity; significant improvements also were observed in histologic architecture. We found that crocin administration nearly eliminated CCl4 induced brain damage by preventing oxidative stress.
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    Protective effects of crocin on biochemistry and histopathology of experimental periodontitis in rats
    (Taylor & Francis Ltd, 2019) Kocaman, G.; Altinoz, E.; Erdemli, M. E.; Gul, M.; Erdemli, Z.; Gul, S.; Bag, H. G.
    We investigated the effectiveness of crocin for preventing oxidative damage in experimentally produced periodontitis. We used three groups of 10 female Wistar rats divided into: control (C); experimental periodontitis (EP), experimental periodontitis + crocin (Cr-EP). Malondialdehyde (MDA), glutathione (GSH), total antioxidant status (TAS), total oxidant status (TOS) and superoxide dismutase (SOD) and catalase (CAT) enzyme activities were measured. We examined histopathology and inflammatory cell infiltration in gingiva and periodontal ligament. MDA and TOS levels, and SOD and CAT activities increased significantly in rats with induced periodontitis compared to the control group, while GSH and TAS levels were decreased significantly compared to the control group. Histopathologic examination revealed inflammatory cell infiltration in gingiva epithelium and subepithelial connective tissue in the EP group. Histological damage was reduced significantly after crocin treatment compared to the EP group. Crocin supplementation may help reduce oxidative damage to periodontal tissues.