THE FUNCTIONAL STATE OF THE HYPOTHALAMO-PITUITARY AXIS AFTER HIGH-DOSE OESTROGEN THERAPY IN EXCESSIVELY TALL GIRLS

Abstract

ABSTRACT Sixteen excessively tall girls were treated with 0.3 mg of ethinyloestradiol daily and 10 mg of norethisterone for 5 days every 3 weeks for 7–26 months. The reduction of adult height varied from 0–12.3 cm, depending on the bone age (115/12–148/12) before treatment. The more advanced the bone age was the less final adult height was reduced. The functional state of the hypothalamo-pituitary axis was assessed by standardized LH-RH testing immediately after termination of therapy as well as 1, 4, 8 and 12 weeks thereafter. Basal levels of oestradiol and prolactin were recorded before each test. Absent LH-responses to LH-RH were observed in all girls when therapy was stopped. Four to eight weeks later the LH responses had normalized in 13 girls and 12 weeks after therapy normal LH responses were found in 14 girls. Mean basal oestradiol levels were low (20 ± 9 pg/ml) (X̄ ± sd) at the end of therapy but increased significantly (P < 0.0025) to levels similar to different stages of the menstrual cycle after 4 weeks. In contrast mean basal prolactin levels were elevated (21±9 ng/ml) (X̄ ± sd) when therapy was stopped. Within one week a significant (P < 0.01) decrease to values averaging 13 ± 4 ng/ml (sd) was seen. A further but only moderate decline occurred until the 12th week after therapy. The decrease of prolactin paralleled to same extend the increase of endogenous oestradiol. All girls experienced spontaneous menstrual bleedings within 3 to 22 weeks after termination of therapy. In all cases but one menses have been regular since. The data presented suggest that no major functional disturbance of the hypothalamo-pituitary axis has to be expected after long-term steroid treatment in excessively tall girls.