Abstract
Objective
To obtain data on the ontogeny of catecholamines and other chromaffin vesicle components, which could serve as a basis for the study of their role during fetal life in normal and pathologic conditions.
Design
Epinephrine, norepinephrine, dopamine-β-hydroxylase, and chromogranin A contents were measured in the porcine adrenal gland during various stages of gestation.
Animals
934 porcine fetuses representing 22 gestational ages between 43 and 108 days.
Procedure
Total homogenates of adrenal glands were extracted and contents of different neurochemical markers were measured, using high-performance liquid chromatography, immunoassays, and western blotting. Immunohistochemical studies also were performed.
Results
Epinephrine and norepinephrine contents as a function of gestational age can be represented by a sigmoidal curve. Norepinephrine content rises early in gestation, whereas epinephrine content increases later. Maximal increase was significantly higher for epinephrine content. A progressive appearance of separate epinephrine- and norepinephrine-storing cells was documented. Dopamine-β-hydroxylase content as a function of gestational age can be adequately represented by a parabolic curve. No quantitative changes in chromogranin A concentration were observed, but western blotting revealed qualitative changes with progressing gestational age.
Conclusions
Important changes occur in catecholamine formation around day 60 of gestation. The sharp increase in epinephrine/norepinephrine contents and the appearance of separate epinephrine- and norepinephrine-storing cells may be related to the progressive splanchnic innervation of the adrenal gland. The presence of chromogranin A early in gestation may indicate its necessity for catecholamine storage. (Am J Vet Res 1996;57:1074–1079)
