ISSN:
1432-0738
Keywords:
Key words Paraquat
;
Dinoseb
;
2
;
4-D Intracellular calcium
;
Rat
;
Hepatocytes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effects of the herbicides paraquat, dinoseb and 2,4-D on intracellular Ca2+ levels and on vasopressin-induced Ca2+ mobilization were investigated in intact isolated hepatocytes. Incubation of rat hepatocytes with paraquat (5 mM for 60 min) and dinoseb (10 μM) resulted in a time-dependent loss of viability by approximately 25%. Viability of cells treated with 2,4-D decreased significantly, dropping to about 20% at 10 mM and 60 min incubation. Exposure of hepatocytes to paraquat (1–10 mM) for 60 min had no effect on the basal level of [Ca2+] i . Additionally, exposure to paraquat had no effect on the magnitude and on the duration of the [Ca2+] i response to vasopressin. In the presence of 2,4-D (1–10 mM), basal [Ca2+] i increases as a function of herbicide concentration. The magnitude of the Δ[Ca2+] i response decreases from 256±8 nM in control to 220±5 nM, at 10 mM 2,4-D. Exposure of hepatocytes to dinoseb (1–10 μM) had no effect on the basal level of [Ca2+] i . However, a strong concentration-dependent decrease in the magnitude of Δ[Ca2+] i in response to vasopressin was noticed at 60 min incubation. Dinoseb markedly inhibited the stimulation of the production of inositol phosphates by vasopressin stimulus. The present study demonstrates that paraquat, 2,4-D and dinoseb cause cell death in hepatocytes by mechanisms not related to an early increase in [Ca2+] i . Additionally, it has been shown for the first time that dinoseb disturbs the transduction mechanism promoted by vasopressin by inhibiting the formation of IP3.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002040050199
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