CIRCULATING CHROMOGRANIN-A AND CATECHOLAMINES IN HUMAN FETUSES AT UNEVENTFUL BIRTH

Chromogranin A (CGA), a large acidic 48-kD protein, co-stored and core leased by exocytosis with catecholamines, has been shown to be a precu rsor of peptides that exert feedback regulatory control on catecholami ne secretion. In plasma, CGA. levels increase in response to a large-a mplitude physical stimulation in adult subjects and may be related to catecholamine levels. Any akin information is not yet available when t he sympathoadrenal system is highly actived during birth. This activat ion is strongly related to parturition circumstances such as the mode of delivery. The aim of our study was to determine CGA plasma levels i n infants delivered vaginally or by elective cesarean section and to i nvestigate the possible correlation between CGA and catecholamine conc entrations. Plasma levels of catecholamines (norepinephrine and epinep hrine) and CGA were assessed by HPLC with electrochemical detection an d immunoenzymology, respectively. CGA and norepinephrine concentration s were significantly higher (p < 0.0002 and p < 0.02) in infants vagin ally born than in the group delivered by elective cesarean section. A significant relationship (p < 0.04) was found between CGA and norepine phrine levels. However, for epinephrine, no significant difference was found between both groups. These results demonstrate the fetus' abili ty to corelease CGA and norepinephrine massively in response to stress of birth.