Asphyxia-induced disaggregation of cerebral polyribosomes in rhesus monkey fetuses.

The effects of 3 hours of controlled intrauterine asphyxia (acidotic hypoxia) on the sedimentation patterns of cerebral polyribosomes and on polyribosome supported in vitro protein synthesis were examined in 16 term monkey fetuses. Three outcomes resulted. Four fetuses showed no changes in polyribosome sedimentation profile or in sedimented polyribosome supported in vitro protein synthesis. Four showed changes in sedimentation profiles indicating partial breakdown of polyribosomes and significant decreases in polyribosome supported in vitro protein synthesis. Finally, 8 fetuses showed almost complete disaggregation of cerebral polyribosomes into 80-S monosomal units. This was associated with marked reduction in sedimented ribosomal mediated in vitro portein synthesis. Both the disaggregation of polyribosomes and the associated loss of in virto protein synthesis were related to the severity of the acidosis produced by asphyxia.