A 17-year-old girl is brought to the physician by her mother for a 5-month history of loss of her menses. She is an avid runner and frequently competes cross country for her school. BMI is 17. Which of the following is the most likely explanation for this patient’s presentation?
A) Decreased serum leptin
B) Increased serum FSH
C) Increased serum GnRH
D) Increased serum LH
E) Primary hypogonadism
