Objective of this study was to characterize osmotically-induced insulin secretion in two tumor cell lines. We compared response of freshly isolated rat pancreatic islets and INS-1 and INS-1E tumor cell lines to high glucose, 30 % hypotonic medium and 20 % hypertonic medium. In Ca2+-containing medium glucose induced insulin release in all three cell types. Hypotonicity induced insulin secretion from islets and INS-1 cells but not from INS-1E cells, in which secretion was inhibited despite similar increase in cell volume in both cell types. GdCl3 (100 μmol/l) did not affect insulin response from INS-1E cells to hypotonic challenge. Hypertonic medium inhibited glucose-induced insulin secretion from islets but not from tumor cells. Noradrenaline (1 μmol/l) inhibited glucose-induced but not swelling-induced insulin secretion from INS-1 cells. Surprisingly, perifusion with Ca2+-depleted medium showed distinct secretory response of INS-1E cells to hypotonicity while that of INS-1 cells was partially inhibited. Functioning glucose-induced insulin secretion is not sufficient prerequisite for hypotonicity-induced response in INS-1E cells suggesting that swelling-induced exocytosis is not essential step in the mechanism mediating glucose-induced insulin secretion. Both cell lines are resistant to inhibitory effect of hyperosmolarity on glucose-induced insulin secretion. Response of INS-1E cells to hypotonicity is inhibited by the presence of Ca2+ in medium., M. Orečná, R. Hafko, Z. Bačová, J. Podskočová, D. Chorvát Jr., V. Štrbák., and Obsahuje bibliografii a bibliografické odkazy
Thyrotropin-releasing hormone (TRH) is also present in pancreatic B-cells and its role and regulation here remain unclear. The rat pancreas displays a peculiar ontogenetic pattern for TRH with a rapid increase after birth up to postnatal day 3 when TRH peak is reached. In the present study, dexamethasone (DXM) treatment (1 ¿/g/lOOg BW/day) resulted in an increase of pancreatic weight and retardation of the peak of pancreatic TRH concentration by two days. The TRH-degrading system (either in the 10 000 x g supernatant or in the pellet of pancreatic homogenate) was not stimulated by in vivo DXM treatment. In DXM-treated rats, plasma TSH levels were significantly decreased after postnatal day 1. Plasma glucose concentration was increased on day 1 (i.e. 24 h after the first DXM injection) and decreased to the control level on postnatal day 3. Pancreatic insulin levels were decreased on postnatal day 3 compared to the controls. These results indicate that DXM affects TRH in the neonatal rat pancreas; this effect is probably not mediated through modulation of TRH-degrading activity. The stimulation of pancreatic growth after DXM treatment might be related to the effect on the TRH system.
Brachylecithum microtesticulatum Timon-David, 1955 (Digenea: Dicrocoeliidae) is recorded for the first time in the Black Sea region. The morphology and variability of the digeneans recovered from Larus argentatus in Bulgaria and the Ukraine are described and compared with the redescription of the species (Bartoli and Mas-Coma 1989). Lyperosomum lari Travassos, 1917 of Smogorzhevskaya (1976) is considered a synonym of B. microtesticulatum.
Recent studies demonstrated remote effects of renal ischemia/reperfusion (I/R) injury on some organs such as brain, liver, and lungs. We investigated the effects of renal I-R injury on function, histology and oxidative stress state of pancreas. Twenty -four male adult Sprague-Dawley rats were divided equally into 2 groups; sham group: rats underwent midline laparotomy and dissection of renal pedicles without renal ischemia, and ischemic group: rats underwent bilateral renal ischemia for 45 min. Renal functions (serum creatinine and BUN), pancreatic functions (serum amylase, lipase and insulin) and fasting blood glucose were measured at 2 h, 1 day, 3 days and 7 days after ischemia. Also, pancreatic histology and malondialdehyde (MDA), catalase and reduced glutathione (GSH) were examined at 2 h and 7 days after ischemia. The ischemic rats showed significant increase in serum creatinine and BUN with significant increase in serum amylase and lipase at 2 h, 1 day and 3 days after ischemia. Blood glucose and fasting insulin showed no significant change apart from significant increase in insulin in sham group at 1 day after ischemia. Pancreas isolated from ischemic rats showed significant increase in histopathological damage score and significant increase in MDA and catalase enzyme with decrease in GSH. In conclusion, bilateral renal ischemia for 45 min caused significant impairment of pancreatic functions and histology. This might be due to deficiency of antioxidant and increased lipid peroxidations in pancreatic tissues., A. M. Hussein ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy