The adrenal glands produce the hormone 17-hydroxyprogesterone (17-OH progesterone). 17-OH progesterone is transformed to the hormone cortisol with the aid of certain enzymes. Various amounts of cortisol are continuously secreted, but periods of physical or mental stress cause cortisol levels to rise. The immune system and metabolism are both controlled by cortisol. People without the necessary enzymes may experience a cortisol deficiency, which may cause an accumulation of 17-OH progesterone in the blood. Congenital adrenal hyperplasia, which is indicated by high levels of 17-OH progesterone (CAH).