Optimizing estrogen replacement treatment in Turner syndrome.

Estrogen has a biphasic effect on growth, stimulatory at low doses but inhibitory at higher doses. Therefore, designing optimal sex hormone replacement treatment in girls with Turner syndrome (TS) who are being treated with growth hormone (GH) involves considering the dose and form of the estrogen as well as the route and timing of its administration. We report here a preliminary analysis of a study to test the concept that an optimal estrogen replacement regimen should consist of estradiol administered in a low dose by a systemic route. The study population consisted of 9 girls with TS who had been treated with GH for 6 or more months. When the girls were 12 to 15 years old, we added depot estradiol at a monthly intramuscular dose of 0.2 mg and increased the dose at 6-month intervals to 0.4, 0.6, and, in 7 of the girls, 0.8 mg. We compared the results in these subjects with those in a matched group of 37 patients with TS in whom routine estrogen treatment had been started at similar ages and who were treated with a similar course of GH therapy. The gain in height at 2 years was 2.6 cm greater in those who were treated with depot estradiol than in those who were treated with routine estrogen. The bone age in the patients who were treated with depot estradiol increased in proportion to their chronologic age, suggesting that this difference indicates an increase in their predicted adult height. We conclude that using very low doses of systemic estradiol to induce puberty before the age of 15 years in girls with TS who are treated with GH, instead of using routine estrogen therapy, can result in increased final heights.

Acute hormonal responses to the gonadotropin releasing hormone agonist leuprolide: dose-response studies and comparison to nafarelin--a clinical research center study.

The hormonal responses to single subcutaneous injection of the GnRH agonist nafarelin have been shown to have considerable potential as a diagnostic test in a number of settings. Since nafarelin injection is no longer produced, studies were conducted to determine the dosage of leuprolide that would yield equivalent responses. Nafarelin 100 micrograms stimulates LH and FSH for 24 h, releasing about 7-fold more gonadotropin than this dose of natural GnRH, which accounts for its ability to elicit gonadal steroid responses. Normal adult men and women were randomized to receive leuprolide doses of 0.1, 1.0, or 10 micrograms/kg; a study extension evaluated doses up to 20 micrograms/kg in men. The responses of LH, FSH, testosterone, and estradiol were monitored for 24 h, and the data were compared to those previously obtained on nafarelin. Leuprolide dose of 10 micrograms/kg yielded LH responses similar to 1-1.5 micrograms/kg nafarelin. However, this leuprolide dose unexpectedly released less FSH than nafarelin. Nevertheless, the gonadotropin responses were sufficient to elicit equivalent or greater sex steroid responses to leuprolide. These studies also further delineated sex-specific differences in pituitary responsiveness to challenge with GnRH agonists: men had a significantly lower baseline FSH level, greater LH release within the first hour, and lesser secretion of LH and FSH over the 24-h period. These studies indicate that leuprolide in a dosage of 10 micrograms/kg would be expected to be efficacious in testing the pituitary-gonadal axis in men and women.