A comparative study of the effect of oestrogen substitution therapy on breast development in girls with hypo- and hypergonadotrophic hypogonadism.

During treatment of girls with oestrogen deficiency we observed different patterns of breast development in response to therapy. The forty-five girls studied fell into four groups: Group A, gonadal dysgenesis; Group B, isolated gonadotrophin deficiency; Group C, multiple pituitary hormone deficiencies; Group D, congenital adrenal hyperplasia (17-alpha-hydroxylase deficiency). Treatment with oestrogen was given in an identical manner to all. In the patients with gonadal dysgenesis, in whom the hypothalamic-pituitary function was normal, treatment led to full breast development. In isolated gonadotrophin deficiency and multiple pituitary hormone deficiency breast development was incomplete even after 3 years or more of oestrogen treatment. The conspicuous difference in the hormonal status is that the latter two groups lack gonadotrophins, while in gonadal dysgenesis these hormones are grossly elevated. Our conclusion is that gonadotrophins play an important role in mammary gland development, a finding not previously described. In the girl with 17-alpha-hydroxylase deficiency we observed that cortisol was necessary, in addition to sex hormones, for normal breast development.