Acceleration of gluconeogenesis following inhibition of protein synthesis in Tetrahymena pyriformis

Abstract

Cycloheximide was found to be a very potent inhibitor of protein synthesis in Tetrahymena pyriformis. Within 1 h following addition of the antibiotic to log phase cultures the decrease in protein synthesis was accompanied by a sharp increase in the incorporation of [2- 14C]acetate and [ 14C]algeal protein hydrolysate into glycogen. Of a number of protein inhibitors tested only emetine clearly reproduced the effects of cycloheximide. Other antibiotics tested were less effective in inhibiting protein synthesis and did not influence gluconeogenesis. The polysome profiles and decreased protein synthesis accompanied by increased gluconeogenesis were similar in cycloheximide treated cultures to those entering the stationary growth phase. The results suggest a causal relationship between inhibition of protein synthesis and initiation of gluconeogenesis.