RESUMEN
We studied the time frame of suppression and recovery of estradiol after injection with leuprolide acetate utilizing an ultrasensitive recombinant cell bioassay for estradiol in eight normal premenopausal women. Previous studies have shown suppression of gonadotropins and estradiol at 4 weeks after the depot injection, but no studies have shown the weekly time course of estradiol suppression or recovery. Four women received one 3.75 mg i.m. injection of leuprolide acetate and four received two 3.75 mg doses of leuprolide acetate 4 weeks apart. Estradiol, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were measured weekly for 8 to 12 weeks. Estradiol was significantly suppressed to 26.6 +/- 19.3% of baseline values by week 3 after the initial dose of leuprolide acetate and suppressed to 2.7 +/- 3.1% of baseline values by week 4 (p < 0.01 versus baseline). The actual values were less than 14.7 pmol/l (4 pg/ml) in all women by week 4. Estradiol remained suppressed for 8 weeks after one dose of leuprolide acetate and remained suppressed for 6 weeks after a second dose administered 4 weeks later. LH and FSH followed a similar pattern, but only remained suppressed for 7 weeks after one dose of leuprolide acetate and for 6 weeks after two doses. Estradiol levels at baseline were significantly correlated with body mass index (BMI). We also studied one postmenopausal woman. Her baseline estradiol levels were 10.3 pmol/l (2.8 pg/ml) and were suppressed to 3.9 pmol/l (1.1 pg/ml) by 2 weeks after leuprolide acetate. In conclusion, estradiol was suppressed to postmenopausal levels by the end of the first month of treatment with leuprolide acetate, as determined by an ultrasensitive bioassay. Higher doses would need to be tested to determine whether greater suppression can be achieved. The hypothalamic-pituitary-gonadal axis begins to recover 7 weeks after one dose and 6 weeks after a second dose of leuprolide acetate. This confirms the adequacy of 4-week dosing to maintain estradiol and gonadotropin suppression in adult women treated with leuprolide acetate, but raises the question whether less frequent dosing may be possible in some situations, or whether higher doses may be needed in some situations for an even greater degree of estradiol suppression.
Asunto(s)
Estradiol/sangre , Fármacos para la Fertilidad Femenina/farmacología , Leuprolida/farmacología , Adulto , Bioensayo/métodos , Femenino , Fármacos para la Fertilidad Femenina/administración & dosificación , Hormona Folículo Estimulante/sangre , Humanos , Leuprolida/administración & dosificación , Hormona Luteinizante/sangre , Persona de Mediana Edad , Análisis Multivariante , Proyectos Piloto , Posmenopausia/sangre , Premenopausia/sangreRESUMEN
OBJECTIVE: Estradiol levels in girls with premature thelarche have not previously been well defined because of the lack of adequate sensitivity of previously available estradiol assays. The ultrasensitive recombinant cell bioassay for estradiol has made the study of estradiol levels in premature thelarche possible. We hypothesized that girls with premature thelarche have higher estradiol levels than normal prepubertal girls. STUDY DESIGN: We used an ultrasensitive recombinant cell bioassay to study estradiol levels in 20 girls with premature thelarche and 15 normal prepubertal girls less than 3 years of age. The 2 groups were compared by Student t test. RESULTS: Estradiol levels were significantly greater in the girls with premature thelarche (8.4 4. 5 pmol/L estradiol equivalents) than in the normal prepubertal girls (3.3 3.5 pmol/L estradiol equivalents; P <.01). The estradiol level was not significantly correlated with age, height, weight, body mass index, age at onset of thelarche, or the presence or absence of ovarian cysts. CONCLUSION: Girls with premature thelarche have significantly higher estradiol levels than normal prepubertal girls. This is consistent with the hypothesis that the mechanism of premature thelarche involves increased estradiol levels rather than increased sensitivity of breast tissue to normal estradiol levels.
Asunto(s)
Mama/crecimiento & desarrollo , Estradiol/sangre , Pubertad Precoz/sangre , Bioensayo , Femenino , Humanos , LactanteRESUMEN
The purpose of this study was to investigate 24-h estradiol and leptin levels in obese and nonobese children to further understand the roles of estradiol and leptin in obesity and puberty. We measured serum estradiol, leptin, insulin, glucose, and GH levels every hour for 24 h in 18 obese (12 females and 6 males) and 30 nonobese (11 females and 19 males) prepubertal and early pubertal (stages 1-2) children. Bone age and dual energy x-ray absortiometry (DEXA) were obtained upon completion of the 24-h study. Obese children were significantly younger than nonobese children, with no difference in pubertal stage, height, or bone age between the 2 groups. Obese children had greater bone age to chronological age ratios than nonobese children, indicating a more advanced rate of bone maturation. Mean 24-h estradiol levels correlated significantly with chronological age and bone age as well as with insulin-like growth factor I, insulin-like growth factor-binding protein-3, dehydroepiandrosterone sulfate, mean 24-h GH, and lean body mass. Mean 24-h estradiol levels did not differ between obese and nonobese children [1.65+/-1.47 us. 2.75+/-3.30 pmol/L (0.45+/-0.40 vs. 0.75+/-0.90 pg/mL), respectively]. Similar mean 24-h estradiol levels in obese and nonobese children are consistent with the increased bone maturation of the obese children. Estradiol did not correlate significantly with DEXA fat mass, body mass index, or arm fat measures of adiposity. Obese children had higher 24-h mean leptin concentrations than nonobese children (28.6+/-17.4 vs. 6.8+/-7.1 ng/mL; P < 0.001). Leptin concentrations positively correlated with DEXA fat mass, body mass index, and arm fat measurement of adiposity. Girls had higher 24-h mean leptin levels than boys when controlling for adiposity. Estradiol and leptin concentrations fluctuated over a 24-h period in both groups, with all children having higher leptin concentrations at night and higher estradiol concentrations in the morning. This diurnal rhythm was of a similar pattern, but at higher levels for leptin and lower levels for estradiol in the obese children compared to nonobese children. There was no significant correlation between estradiol and leptin levels. Bone mineral density, as measured by DEXA, did not differ between obese and nonobese children. Similar bone mineral density values in obese and nonobese children are consistent with the increased bone maturation of the obese children. Bone mineral density was not correlated with estradiol or leptin level in these children. In conclusion, obese children had similar estradiol levels and equivalent bone ages at a younger chronological age than nonobese children. Leptin was higher in these obese children, but did not correlate with estradiol level or bone age. These findings suggest that the role of leptin in both obesity and pubertal development is not directly correlated with the estradiol level.