A 28-year-old lady has put on weight (10 kg over a period of 3 years) and has oligomenorrhoea followed by amenorrhea for 8 months. The blood pressure is 160/100 mm of Hg. Which of the following is the most appropriate investigation?
Serum electrolytes
Plasma cortisol
Plasma testosterone and ultrasound evaluation of pelvis
T3, T4 and TSH
T3, T4 and TSH