Differential effects of two organophosphorus pesticides on polyamine metabolism in toad embryos

PIRES, NATALIA SUSANA; VENTURINO, ANDRÉS; LASCANO, CECILIA

Córdoba

Congreso; 52° Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

Organophosphorus pesticides like chlorpyrifos(CPF) and azinphosmethyl (AZM) are widely applied in the fruit-producing valleyof Río Negro and Neuquén. Amphibian embryos are particularlysensitive to numerous environmental contaminants. Polyamines(PA) are essential for normal cell growth and differentiation, being highlyregulated through the balance in the first-step synthesizing enzyme ornithinedescarboxylase (ODC) and degradation by polyamino-(APAO), diamino-(DAO) andspermine (SMO) oxidases. Our objective was to evaluate the effects of AZM and CPFon PA oxidation in R. arenarumembryo, measuring oxidase activities through kinetic spectrofluorometryanalysis. SMO and DAO activities were increased by 9 mg/L AZM (62% and 69%) inearly embryos (3d), while the effect was highly noticeable on APAO (4-foldincrease). CPF did not affect oxidases in early stages. At the end of embryodevelopment AZM effect was smoother on DAO (20% increase) but sustained on SMOby 2 mg/L exposure (70% increase). Only a minor decrease (10%) was caused byCPF. According with our previous results, alterations caused by AZM in lateembryos may be related to an increase in putrescine driven both by ODCinduction and spermidine/ spermine oxidation back to diamine. Conversely, thedecrease in PA reported in early embryos exposed to CPF would be only relatedto the decrease in ODC as oxidases are not affected.