In Which cell organelles Steroid synthesis Occurs?

Steroid synthesis occurs mainly in the smooth endoplasmic reticulum and the mitochondria of cells.

Many of the enzymes for sterol and steroid synthesis are localized in the smooth-surfaced endoplasmic reticulum (2, 3). This organelle is particularly prominent in cells of the inner zones of the adrenal and fluctuates in amount and configuration in response to hormonal stimulation and sterol levels (4–7).