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. Author manuscript; available in PMC: 2013 Dec 2.
Published in final edited form as: J Steroid Biochem Mol Biol. 2009 Dec 28;122(1-3):42–52. doi: 10.1016/j.jsbmb.2009.12.010

Fig. 1.

Fig. 1

Steroidogenesis occurring both in gonads and adrenal gland of human origin. As cholesterol is the precursor for all steroids, each zone of the adrenal gland or cell types of the ovary expresses specific enzymes necessary for appropriate steroid production. The ovaries, more particularly the thecal cells, possesses the P450c17 enzyme having both the 17α-hydroxylase/17,20-lyase activities needed for androgens secretions, DHEA/testosterone. Granulosa cells expresses the P450aromatase enzyme necessary for estrogens production. The adrenal gland has the capacity to secrete mineralocorticoid (aldosterone) due to the presence of the P450aldo synthase enzyme in the zona glomerulosa. The adrenal gland zona fasciculata, and to a much lesser extent the zona reticularis, produces glucocorticoid (such as cortisol in human) because they express the 17α-hydroxylase activity of the P450c17 enzyme. The zona reticularis expresses to a larger extent than the zona fasciculata both 17α-hydroxylase and 17,20-lyase activities of the P450c17 that are necessary to produce androgens, adapted from Ref. [13].