GONADOTROPIN PULSATILITY IN GIRLS WITH THE TURNER-SYNDROME - MODULATION BY EXOGENOUS SEX STEROIDS

Citation
Nc. Nathwani et al., GONADOTROPIN PULSATILITY IN GIRLS WITH THE TURNER-SYNDROME - MODULATION BY EXOGENOUS SEX STEROIDS, Clinical endocrinology, 49(1), 1998, pp. 107-113
Citations number
23
Categorie Soggetti
Endocrynology & Metabolism
Journal title
ISSN journal
03000664
Volume
49
Issue
1
Year of publication
1998
Pages
107 - 113
Database
ISI
SICI code
0300-0664(1998)49:1<107:GPIGWT>2.0.ZU;2-V
Abstract
OBJECTIVES The endocrine manisfestation of puberty, nocturnal pulsatil e secretion of gonadotrophins precedes the physical manifestations by 2 years. Whether gonadal steroids and inhibin have a role to play in t he regulation of pulsatile gonadotrophin release is unclear, The agona dal model, girls with Turner's syndrome (TS), has been used to determi ne the role of the hypothalamic pulse generator in the ontogeny of gon adotrophin secretion in man, We evaluated the ontogeny of gonadotrophi n secretion in TS girls with respect to amplitude and frequency and co mpared these results to those obtained in a group of normal girls. The effects of treatment with ethinyloestradiol (EE,) or oxandrolone (OX) on parameters of gonadotrophin secretion were also evaluated, PATIENT S We studied 32 girls with TS, aged 4.3-1.2 4 years. All were prepuber tal at the start of the study and longterm follow up revealed that non e entered spontaneous puberty. The pulse amplitude and frequency was e valuated and compared to the results obtained in 23 normal girls, aged 4.9-12.8 years who acted as controls, MEASUREMENTS Samples were taken at 20 minute intervals for 24 h for the measurement of serum concentr ations of luteinising (LH) and follicle stimulating (FSH) hormones, Th e girls were than randomized to receive EE2 or OX and were then re-adm itted 6 months into the course of the treatment for a repeat 24h serum profile of LH and FSH levels. RESULTS The girls with TS showed a clea rly defined dominant pulse periodicity of 180 min and that in the norm al cohort was 160-220 min. The girls with TS had an increased oscillat ory activity between 120 and 260min compared to the normal, Mean 24h s erum gonadotrophin concentration in TS girls was always higher than in the normal cohort, The inflection points of the fitted polynominal re gression equation relating sex hormone concentration with age was simi lar for the two groups, EE2 lead to a significant change in pulse peri odicity in TS girls but OX had no significant effect on the pulse peri odicity. CONCLUSION These results demonstrate that girls with Turner s yndrome have gonadotrophin pulse periodicity in the prepubertal years similar to those of normal girls, The oscillatory activity was much gr eater in girls with Turner syndrome at all ages in the prepubertal yea rs, suggesting a role for the ovary in modulating gonadotrophin secret ion in the prepubertal years, Our data confirm that in girls with Turn er syndrome the normal pattern of gonadotrophin secretion evolving wit h time is preserved.