Change in levels of cyclic AMP and cyclic GMP during pregnancy and larval development of the tsetse fly, Glossina morsitans

Abstract 1. 1. Cyclic AMP and cyclic GMP levels change very little in response to feeding and mating, but during pregnancy and at parturition major changes can be detected in both the mother and larva. 2. 2. In both the female head and larva (whole body) cyclic AMP levels reach a peak at parturition. In the larval brain and ring gland cyclic AMP is at its lowest at parturition but rises sharply, reaching a peak 1.5 hr later at the time of pupariation. 3. 3. Though cyclic AMP levels in the head and thorax are consistently 10–60 times greater than levels of cyclic GMP, both the female abdomen and larva contain high concentrations of cyclic GMP with a ratio of cyclic AMP: cyclic GMP approaching 1:1. In the abdomen, the pattern of high cyclic GMP closely parallels the activity cycle of the female's milk gland.