Browsing by Author "Yesilbas, Ayse"

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Investigation of Some Hormones Affecting Osmoregulation of Lake Van Fish (Alburnus Tarichi) During Reproductive Migration
(Wiley, 2022) Yesilbas, Ayse; Oguz, Ahmet Regaib
Lake Van is one of the largest soda lakes in the world. The extreme characteristics of the lake greatly limit the animals living there. Lake Van fish (Alburnus tarichi Guldenstadt, 1814) is the only vertebrate species that has adapted to this environment. Lake Van fish migrate to freshwater every year to breed, after which, they return to the lake environment. The fish are exposed to different aquatic environments during migration. The endocrine mechanisms involved in the physiological changes during this migration are not studied in this species, yet. In this study, water and serum sodium, potassium and chloride levels in the lake, downstream and upstream to which Lake Van fish are exposed during reproductive migration were determined. Circulating cortisol, free triiodothyronine, free thyroxine, insulin-like growth factor-I, growth hormone and prolactin levels were also investigated. It was observed that the water ion levels decreased in the freshwater localities when compared to the lake localities, and the serum Na+ and Cl- levels decreased in upstream1 and upstream2, K+ levels stayed at a certain level in all localities. It was determined that the hormone levels differed in the upper regions of the river (upstream1 and upstream2), where spawning was completed, from the lake environment, where reproductive migration began. Results indicate that the studied hormones had direct and indirect effects on osmoregulation in the Lake Van fish with the physiological tendency to keep osmotic homeostasis, as occurs in other teleost species.
Investigation of the Therapeutic Effect of Melatonin on Deltamethrin Applied Mouse Primary Hepatocyte Culture
(Taylor & Francis Ltd, 2025) Kaval Oguz, Elif; Oguz, Ahmet Regaib; Ozok, Necati; Alkan, Zehra; Ergoz Azizoglu, Burcu; Orgi, Elif; Yesilbas, Ayse
ObjectiveIn recent years, it has been known that the melatonin hormone, secreted from the pineal gland, possesses significant antioxidant activity. This study explores the therapeutic effect of melatonin on the deleterious effects of deltamethrin, a pyrethroid pesticide extensively used worldwide, including in T & uuml;rkiye, on mouse liver cells.MethodsHepatocytes from Balb/C mice were isolated using a two-stage perfusion method, resulting in over 85% live hepatocytes. The isolated cells were cultured with different doses of deltamethrin (1 and 10 mu M) and melatonin (100 mu M) for 24 and 48 hours. At the conclusion of the culture period, hepatocytes were extracted at the 24th and 48th hours, and Malondialdehyde (MDA), Total Antioxidant Capacity (TAC), Total Oxidation Status (TOS), and DNA damages (8-hydroxy-2'-deoxyguanosine (8-OHdG)) were examined.ResultsWhile an increase in MDA, TOS, and DNA damage was observed in the deltamethrin-administered groups of hepatocytes, a decrease in TAC level was noted. It was determined that the applied deltamethrin had no effect on cell viability throughout the application period.ConclusionFurthermore, it was observed that melatonin, when administered concurrently with deltamethrin, reduced the toxic effect of deltamethrin. This study suggests that melatonin has a protective effect against deltamethrin-induced damage in mouse hepatocyte cells.