title: Diurnal rhythm of 17 beta-estradiol secretion throughout pubertal development in healthy girls: evaluation by a sensitive radioimmunoassay.
abstract: Puberty is initiated by a nocturnal rise in gonadotropin secretion, which, in boys, results in an increased nocturnal secretion of testosterone. To characterize any similar diurnal rhythm of 17 beta-estradiol in healthy girls, we determined the secretion of 17 beta-estradiol before and during puberty. The study group consisted of 45 healthy girls whose height SD scores ranged from -3.7 to +4.9 compared with Swedish growth reference values. One to 6 profiles of 17 beta-estradiol (7 samples/24 h) were obtained from each girl during puberty and from 21 of the girls before clinical signs of puberty (a total of 76 serum profiles). Serum 17 beta-estradiol concentrations were determined using a modified RIA. The detection limit for the RIA was 1.8 fmol/tube, which corresponded to a serum level of 7.8 pmol/L in extracted serum. It was considered that levels above 50 pmol/L could be determined accurately without extraction. The serum levels of 17 beta-estradiol in prepubertal girls were, in most cases, below the detection limit, except in the morning, when in 17 of the 21 prepubertal girls, serum 17 beta-estradiol levels were just above the detection limit. All girls in early puberty (Tanner breast stage 2) had measurable serum levels of 17 beta-estradiol in the morning, whereas 10 of these 15 girls had levels below the detection limit around midnight. Later in puberty (Tanner breast stages 3 and 4), but before menarche, the diurnal rhythm was more obvious, with high levels of 17 beta-estradiol during the latter part of the night and in the morning. This diurnal rhythm was lost by 1 yr after menarche. There was a high degree of correlation between serum concentrations of 17 beta-estradiol and bone age, whereas there was much less, if any, correlation between 17 beta-estradiol and levels of sex hormone-binding globulin or dehydroepiandrosterone sulfate during puberty. We conclude that the nocturnal rise in gonadotropin secretion during puberty in girls is accompanied by an increased secretion of 17 beta-estradiol in the morning. This diurnal rhythm is lost 1 yr after menarche. Determination of 17 beta-estradiol levels in the morning could be useful in determining the initiation of puberty, whereas determinations in the late evening could provide information on the tempo of puberty.
authors.affiliation: Department of Pediatrics, University of Göteborg, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Norjavaara
authors.forename: C
authors.initials: C
authors.lastname: Ankarberg
authors.forename: K
authors.initials: K
authors.lastname: Albertsson-Wikland
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton; D000367:Age Factors; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D004958:Estradiol / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008572:Menarche / Q000097:blood / Q000502:physiology; D011627:Puberty / Q000097:blood / Q000502:physiology*; D011863:Radioimmunoassay / Q000379:methods / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism
chemical_list: D012738:Sex Hormone-Binding Globulin; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate; D006854:Hydrocortisone