NORMAL NEONATAL SURGE OF GONADOTROPHINS AND SEX STEROIDS IN INFANTS OF MEN WITH ISOLATED HYPOGONADOTROPHIC HYPOGONADISM

The inheritance of isolated hypogonadotrophic hypogonadism (IHH) is not fully determined. Although men with this diagnosis can be treated to induce fertility, it is not known whether their offspring will inherit the hormonal deficiency. We evaluated the hypothalamic-pituitary-gonadal axis in nine children (born to men with IHH) during the first few months of life. This axis normally shows activation in infancy similar to that which occurs at puberty. Luteinizing hormone (LH) releasing hormone stimulated a peak LH response in excess of prepubertal levels (39.0 +/- 11 mIU/ml [mean +/- SD]). Testosterone in males (6.2 +/- 2.8 nmol/l and oestradiol in two of the females (320 and 100 pmol/l) were also in excess of prepubertal levels. These infants of men with IHH showed no evidence of inheriting hypogonadotrophic hypogonadism. While further studies will be conducted at the usual age of puberty to confirm spontaneous activation of the hypothalamic-pituitary-gonadal axis, our studies suggest that it may be possible to assess the integrity of this axis at a much younger age.