Gender differences in the effect of salinity on aldicarb uptake, elimination, and in vitro metabolism in Japanese medaka, Oryzias latipes. Aquat Toxicol 2002 Dec 03;61(3-4):225-32
Date
10/03/2002Pubmed ID
12359392DOI
10.1016/s0166-445x(02)00059-0Scopus ID
2-s2.0-0037015946 (requires institutional sign-in at Scopus site) 9 CitationsAbstract
Toxicity studies have shown that salinity enhances the toxicity of aldicarb to female Japanese medaka. Although previous studies indicated that biotransformation may be important in these effects, other dispositional factors may play a role in this scenario. Male and female medaka were separately acclimated to three salinity regimens: 1.5, 12, and 20 parts per thousand (per thousand) for 2 weeks. The fish were then aqueously exposed to 96 h LC(20) of [(14)C]aldicarb for 24 h. [(14)C]aldicarb equivalents (aldicarb and its metabolites) were measured in whole-fish homogenates of half the fish. The other half of the population was transferred to clean water for 48 h. During this 48 h period, fish were removed and whole animal homogenates were measured radiometrically at 0, 2, 4, 8, 12, and 24 h time points. Salinity did not have an effect on the uptake of aldicarb in either male or female medaka. Elimination data showed that elimination of [(14)C]aldicarb equivalents was biphasic. Salinity did not have an effect on the elimination half life in either males or females. In vitro metabolism using gill and liver microsomes from fish acclimated to three salinity regimens showed that aldicarb sulfoxide production by male gill microsomes increased 6-fold by salinity compared to a 9-fold increase in female gills. In conclusion, the increased sensitivity of female medaka to salinity enhanced toxicity seems to be caused by a higher metabolic activation of aldicarb to the sulfoxide compared to the males. This study supports the hypothesis that the differential expression and regulation of FMOs is an important factor in determining the sensitivity of euryhaline fish to aldicarb, especially at high salinity regimens.
Author List
El-Alfy AT, Bernache E, Schlenk DAuthor
Abir El-Alfy PhD Assistant Dean, Professor in the School of Pharmacy Administration department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AldicarbAnimals
Biotransformation
Carbon Radioisotopes
Female
Gills
Hydrogen-Ion Concentration
Insecticides
Male
Microsomes
Microsomes, Liver
Oryzias
Sex Characteristics
Sodium Chloride
