blood pressure. Cushing's syndrome results from excessive exposure to the hormone cortisol. Cortisol increases blood pressure by increasing the sensitivity of the blood vessels to epinephrine and norepinephrine. Aldosteronism occurs due to oversecretion of aldosterone. One function of aldosterone is to indirectly stimulate the reabsorbtion of water from the kidney tubule cells into the systemic circulation. This process increases blood volume and thus blood pressure.