ADULT HEIGHT COMPARISON BETWEEN BOYS AND GIRLS WITH PRECOCIOUS PUBERTY AFTER LONG-TERM GONADOTROPIN-RELEASING-HORMONE ANALOG THERAPY

We examined 22 girls and 11 boys with idiopathic precocious puberty (I PP) treated with a GnRH analogue for a period of about 4 y. The purpos e of our study was to evaluate possible differences between the two se xes in bone growth and skeletal maturation during treatment and in the achievement of final height, and also to study the relative contribut ion of particular hormones-sex steroids, DHEAS, GH and IGF-I-during th e pubertal growth spurt. At the beginning of therapy mean chronologica l age (CA) was 7.61 +/- 0.84 y in boys and 7.32 +/- 1.06 y in girls. A fter the first year of treatment, growth velocity and Delta bone age/D elta chronological age (Delta BA/Delta CA) ratio had declined signific antly in both groups. At the end of therapy we observed a statisticall y relevant increase in predicted adult height in both sexes, with a mo re appreciable mean gain (expressed as SDS) being achieved by male pat ients. During the first year following discontinuation of treatment, a significant increase in the Delta BA/Delta CA ratio was observed in b oth males and females; by contrast, growth velocity increased only in male patients. Adult height SDS was thus greater in boys (0.13 +/- 0.9 1) than in girls (-0.62 +/- 0.88, p < 0.05). With regard to endocrinol ogical data, oestradiol and testosterone were significantly reduced du ring the first year of therapy, while DHEAS levels increased slightly in both sexes throughout thr course of treatment. GH peak after clonid ine and IGF-I concentrations remained unchanged in both groups. Also, a study of nocturnal GH secretion (10 subjects) showed no noteworthy d ecrease in any of the patients, whether in terms of mean GH, of the su m of pulse amplitudes, or of pulse frequency. In conclusion, our data indicate that boys achieve more significant results in terms of adult height than girls. With reference to endocrinological data, the effect of sex steroids on bone maturation seems to be more significant than previously thought, and we hypothesize a different role for androgens and oestrogens in regulating height velocity and bone maturation in bo th male and female subjects during pubertal growth spurt.