Protein kinase activities in Bufo arenarum embryos exposed to azinphosmethyl and carbaryl

FERRARI A; VENTURINO A; PECHEN DE D'ANGELO A.M

Rosario

Congreso; 42ª Reunión Anual de la SAIB; 2006

SAIB

Most relevant efforts to understand pesticide actions are presently directed to cellular signaling and gene response. We evaluate here the effects of azinphosmethyl (AM, 9mg/L) and carbaryl (CB, 20mg/L) on basal protein kinase, PKC and PKA activities in Bufo arenarum larvae after continuous exposure from fertilization. The activity of the oxidative stress- responding enzyme GST was also evaluated. Kinase assay (32PgATP; Histone) conditions were fitted using adult toad brain. Control larvae showed a significant basal kinase (30.2 dpm/µg protein) and PKA (cAMP-activated phosphorylation; 12.7 dpm/µg protein) activity, but PKC (DAG/PC-activated phosphorylation) was absent at this stage. Exposure to AM caused a significant increase of basal kinase (199%) and PKA (192%), and activated PKC (22.6 dpm/µg protein). Exposure to CB only produced a significant increase in basal kinase activity (124%). Larvae showed an induction of GST activity due to AM exposure (71%) and to a lesser extent to CB (33%) (p<0.01). The induction of PKC and PKA observed with AM could be related to the degree of oxidative stress generated by AM compared to CB as suggested by GST induction levels. The appearance of PKC activity in treated embryos may be associated with cell ability to induce detoxifying enzymes such as GST via Nrf2-ARE in response to electrophilic contaminants.