Effect of Methyl parathion, JH III and EDTA on the Biological Half-Life of Proctolin in the Desert Locust, Schistocerca gregaria Forsk.

The effect of methyl parathion JH HI and EDTA, at 1x10 M, lug g⁻¹ body weight and lxl0⁻⁵ M respectively is reported on the biological half-life of proctolin under semi-in vivo and in vivo conditions, in the desert locust, Schistocerca gregaria. Under semi in vivi and in vivo conditions, the half life of untreated proctolin was 48.10 sec and on treatment with methyl parathion, EDTA and JH III respectively, was 7.3, 3.7 and 12 times that of control. In vivo studies, however, indicated that proctolin degraded faster in methyl parathion treated insect (t_1/2 1644 sec), EDTA treated insect (t_1/2 415 sec) and JH-III treated hoppers (t_1/2 1274 sec) as compared to the untreated insect (t_1/2 22378 sec). Proctolin exhibited a phenomenon of negative cobperativity to its binding site(s) which was reduced in the presence of xenobiotics.