Radiorespirometric determination of contribution of pentose phosphate cycle to metabolism of glucose in dermacentor andersoni

ABSTRACT

The contribution of both pentose phosphate cycle [PPC] and glycolytic-citric acid cycle [GCAC] to metabolism of glucose by different physiological states of Dermacentor andersoni female was evaluated. The radiorespirometric method was used after injection of glucose 3,4-[14]C [G[3,4]] glucose-1-[14]C [G[1]] and glucose-6-[14]C [G[6]] into the hemocoel of separate females of different physiological states and following by the expired [14]CO[2], was trapped for 7 hrs. at 1 hr. intervals. The contribution of PPC to glucose metabolism is 23, 50 and 84% in the unfed, unmated-partly fed, and ovipositing females respectively. Accordingly, the GCAC contribution is 77, 50 and 16% in the same physiological states respectively. The greatly increasing trend in PPC activity from the unfed to the ovipositing state is attributed to increasing need to requisite two-carbon unit intermediates for other metabolic processes. The metabolic products of PPC used in biosynthetic processes associated with feeding and oogenesis is a reliable reason for the active operation of this metabolic pathway