<prompt> A 25-year-old lady has put on weight and has oligomenorrhea followed by amenorrhea for 8 months. The blood pressure is 160100 mm of Hg. Which of the following is the most appropriate investigation?Serum electrolytesPlasma cortisolPlasma testosterone and USGT3, T4 and TSH  <response>: Ans. B. Plasma cortisolThe given clinical situation suggests a diagnosis of Cushings which is diagnosed by Cortisol levels. Weight gain with oligomenorrhea points to Cushings syndrome. Cortisol inhibits gonadotropin release that explains amenorrhea. Hypertension in these patients is secondary to increased cortisol that has some mineralocorticoid activity also. 