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Localization of G Protein α-Subunits in the Human Fetal Adrenal Gland 1

2000; Oxford University Press; Volume: 141; Issue: 12 Linguagem: Inglês

10.1210/endo.141.12.7834

1945-7170

Lyne Breault, Estelle Chamoux, Jean‐Guy Lehoux, Nicole Gallo‐Payet,

Estrogen and related hormone effects

The aim of the present study was to investigate the presence and localization of the main G protein α-subunits in the human fetal adrenal gland during the second trimester of gestation. Immunofluorescence studies conducted on sections from frozen glands obtained immediately after therapeutic abortion indicated that the αs subunit of the heterotrimeric Gs protein was detected in all adrenal cell types, except for endothelial cells. The otherα -subunits had a more specific pattern of distribution. Indeed, theα i1–2 protein was restricted to the definitive zone, whereas αi3 labeling was mainly expressed in the fetal zone. The αq protein subunit was localized in vascular endothelial cells at the periphery of the adrenal gland and in fetal cells at the center. Finally, chromaffin cells expressed αs, αq, and αo1, but not αo2 nor αi. Altogether, these results indicate that the human fetal adrenal gland is not only unique in its particular morphology and expression of steroidogenic enzymes, but also by the differential expression of G protein α-subunits. Such cell specific distribution in glands from midgestational fetuses may account for the absence or the different responses to stimuli, when compared with the adult adrenal gland.