Gonadal-pituitary hormone levels in gynaecomastia.

Plasma levels of LH, FSH, oestradiol 17 beta and testosterone were measured in twenty-two men with gynaecomastia. The group was divided by age into those under and those over 50-years-old and the mean hormone levels of the two groups were compared with two groups of age-matched normal men. In the young men with gynaecomastia LH and consequently the LH:FSH ratio was lower than in controls. Older patients with gynaecomastia had higher values of both LH and FSH than normal controls but the LH:FSH ratio was similar in the two groups. A pulsatile pattern of LH was present only in the young controls. Older controls had higher FSH levels than younger controls. In older men with gynaecomastia oestradiol levels and the oestradiol:testosterone ratio were higher than in those without.