SW Group Research Articles

The composition of diet in conjunction with chronic ethanol consumption alters plasma proteinase inhibitor levels in rats.

To study the effects of dietary composition and chronic ethanol ingestion on plasma proteinase inhibitor (PI) levels in intact animals, 192 male Wistar rats were divided into 4 groups, which received a standard diet (S), a fat-rich diet (F), a protein-rich diet (P), and a carbohydrate-rich diet (C), respectively, for 12 weeks. Half of the animals in each diet group had 15% ethanol as their drinking solution (A) during this diet period, and the rest drank tap water (W). FW and CW diets caused a significant decrease in the trypsin-inhibiting capacity (TIC) of plasma in comparison with the SW group (p less than 0.05 and p less than 0.001, respectively), and chronic ethanol ingestion in combination with P and C diets decreased plasma TIC levels significantly (p less than 0.01 and p less than 0.001) when compared with the corresponding water-drinking groups. The chymotrypsin-inhibiting capacity (CIC) of plasma behaved differently: in the FW, PW, and CW groups it was significantly higher than in the SW group (p less than 0.001). Chronic ethanol ingestion did not change plasma CIC levels significantly when compared with the corresponding water-receiving groups. In conclusion, dietary intake was found to alter plasma PI levels. Changes in the protein synthesis of the liver might be responsible for these alterations.

Changes of (Na +-K +) dependent ATPase activity in gills and kidneys of two mullets Chelon labrosus (Risso) and Liza ramada (Risso) during fresh water adaptation

Na+/K+–ATPase (NKA) is a primary active pump provides the driving force for ion-transporting systems in the osmoregulatory tissues of teleosts. Therefore, modulation of NKA expression or activity and its regulatory subunit, FXYD protein, is essential for teleosts in salinity adaptation. To understand the mechanisms for modulation of NKA in catadromous fishes, NKA expression and activity, cloning and mRNA expression of FXYD11 (AjFXYD11) were examined in Japanese eel (Anguilla japonica) exposed to fresh water (FW) and seawater (SW; 35‰). Expression and activity of NKA as well as mRNA expression of AjFXYD11 in gills were elevated in SW eel compared to FW eel. Conversely, NKA responses in eel kidneys were higher in FW group than SW group, whereas no significant difference was found in renal AjFXYD11 expression between the two groups. Comparison of NKA activity and AjFXYD11 expression between two osmoregulatory tissues suggested that AjFXYD11 plays a specific, functional role in gills. However, since cortisol plays an important role for regulation of ion transport in teleost SW acclimation and gill AjFXYD11 expression was elevated in SW eel, the organ culture approach was used to study the effect of cortisol on gill AjFXYD11 mRNA expression. Our results revealed that cortisol treatment increased the levels of gill AjFXYD11 transcripts. This finding suggested that cortisol could be involved in the regulation of NKA by altering AjFXYD11 expression during the process of SW acclimation in A. japonica. Taken together, the differential expression of branchial and renal NKA and AjFXYD11 implicated their roles in the osmotic homeostasis of Japanese eel exposed to environments of different salinities.