Recovery from functional hypogonadotropic hypogonadism. Subjects underwent neuroendocrine profiling (every 10 minutes × 12 hours) to chart GnRH-induced LH secretion. (A) Patient 5 exhibited nocturnal sleep-entrained LH pulses and hypogonadal serum T (225 ng/dL, 7.8 nmol/L). (B) After weight gain, repeat frequent sampling showed normal LH pulse frequency and amplitude with normal serum T (442 ng/dL, 15.3 nmol/L). Note: The study was stopped at 11 hours of sampling because of a problem with the IV. Shaded region represents the normal reference range (27). Inverted triangles indicate LH pulses. The hatched bars depict periods of sleep.