Gonadotropin regulation during puberty in complete androgen insensitivity syndrome with testicles in situ

This paper describes the time course of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in two patients with the complete androgen insensitivity syndrome (AIS) during puberty and adolescence prior to gonadectomy. In early puberty, LH values were comparable to normal male as well as female standards. At the age of 17 and 18.7 years, respectively, a sudden rise in LH occurred just after the start of estradiol supplementation. These high LH concentrations in the late puberty of our patients are comparable to the values found during early puberty in castrated individuals and children with gonadal dysgenesis. In contrast, FSH concentrations continuously showed levels in the normal male or female range with no rise during adolescence. The sudden increase of LH in late puberty is most probably due to defective testosterone receptors in the pituitary/hypothalamus which apparently can no longer be suppressed by rising testosterone levels and an escape from the negative estradiol feedback. The role of estradiol supplementation might be incidental and further investigation into its role is needed. In contrast to the elevated levels of FSH in patients with defective spermatogenesis, FSH is normal in our patients with AIS and testes in situ. This indicates that FSH secretion is regulated by a combined action of estradiol and gonadal hormones like inhibin.