The activities of Δ
5-3β-hydroxysteroid dehydrogenase (3β-HSD; EC 1.1.1.51) and glucose-6-phosphate dehydrogenase (G-6-PDH; EC 1.1.1.49) in the adrenal cortex of virgin rats during the estrous cycle were measured by microspectro-photometry.
3β-HSD activity was found throughout the cortex, and was especially high in the outer part of the zona fasciculata and the juxtamedullar cell layer during estrus. The HSD-positive cells had a high lipid content, a well developed smooth endoplasmic reticulum (SER) and globular mitochondria with many vesicular cristae. Reaction products of 3β-HSD were found on the outer surface membrane of the SER, and in the cristae of the mitochondria, particularly in the swollen cristae.
The distribution of G-6-PDH was similar to that of 3β-HSD.
These results suggest that steroidogenesis in the adrenal cortex increases in estrus, activating both the SER and mitochondria in cells of the zona fasciculata and the juxtamedullar cell layer.
View full abstract