Fetal and early postnatal development of adenylate cyclase and cyclic AMP phosphodiesterase acitvities in rat brain.

Abstract

Brain cyclic AMP metabolism was studied in rat offspring at 17, 19 and 21 days of intrauterine life and 0, l and 4 postnatal qays. Wet weight and protein and DNA and RNA concentrations in brain increased in parallel with body weight until the 4th postnatal day although during the perinatal phase some of these parameters suffered a manifest temporal retardation. In the brain, similar qualitative changes were observed in both adenylate cyclase and high Km cyclic AMP phosphodiesterase activity while the low Km enzyme showed a rise from 17-day fetuses to those of 19 days with no further changes. The increase in cyclic AMP concentration was very mild and the values found in the 21-day fetuses were already similar to those in adults. In the mother's brain a significant reduction in adenylate cyclase activity appeared at 19 and 21 days of gestation. The retardation in the ontogenic development of cyclic AMP metabolism during the perinatal phase in offspring is probably a consequence of their specific metabolic situation while in the mother it may be the result of its endocrine preparation for parturition.