Intestinal absorption of the acetamiprid neonicotinoid by Caco-2 cells: Transepithelial transport,cellular uptake and efflux

The human intestinal absorption of acetamiprid (AAP) using the Caco-2 cell line reveals that AAP flux was active in a bidirectional mode with an apparent permeability coefficient of 26^.10^?6 cm·s^?1 at 37°C. Apical uptake was concentration-dependent and unsaturated for AAP concentrations up to 200 μ M. AAP cell preloading demonstrated the involvement of active transport mechanisms. Arrhenius plot analysis revealed an unusual profile with two apparent activation energies suggesting two transport processes. Uptake Vi studies indicated the involvement of a sodium-dependent transporter, the presence of a common transporter of AAP and nicotine and the involvement of Ti-sensitive ATP-dependent efflux transporters. Apical efflux investigations showed the involvement of inward active transporter(s). Whereas vincristine had no effect on intracellular accumulation, taxol and daunorubicin treatments unexpectedly led to 10% and 23% reductions respectively, suggesting that the latter shared a common inward transporter with AAP. All these results suggest full and express AAP absorption in vivo with transport involving both inward and outward, passive and active mechanisms. Thus, AAP or its metabolites could be representative of a risk for human health after its ingestion in food.     

The influence of deoxynivalenol and zearalenone on steroid hormone production by porcine ovarian granulosa cells in vitro

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) are frequently occurring in feed of pigs together. The aim of this study was to evaluate the possible in vitro effects of DON and ZEA, alone or their combination on steroid secretion of porcine ovarian granulosa cells (GCs). A species-specific model with porcine ovarian GCs was used to study the potential endocrine disrupting effects of DON and ZEA alone and in co-exposure. Progesterone (P4) and estradiol (E2) were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). The results of this study demonstrate that DON alone at the higher concentrations may act to stimulate P4 (at 1,000, 2,000, 3,000 and 5,000 ng mL^?1 but not 10 and 100 ng mL^?1) and E2 (at 2,000, 3,000 and 5,000 ng mL^?1 but not 10, 100 and 1000 ng mL^?1) secretion. The effects of ZEA on P4 and E2 secretion were not confirmed. DON in combination with the other fusariotoxin ZEA may impair steroidogenesis. Results aslo demonstrate different toxicological effects of fusariotoxins on follicle stimulating hormone-induced secretion of P4 and E2. All these results taken together suggest that fusariotoxin and their interactions can impact ovarian steroidogenesis, thereby demonstrating their potential reproductive effects in pigs.