Diurnal rhythm of 17 beta-estradiol secretion throughout pubertal development in healthy girls: evaluation by a sensitive radioimmunoassay.

• 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.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Pediatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Pediatrics (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Adolescent

Age Determination by Skeleton

Age Factors

Child

Circadian Rhythm

physiology

Dehydroepiandrosterone Sulfate

blood

Estradiol

blood

secretion

Female

Humans

Hydrocortisone

blood

Male

Menarche

blood

physiology

Puberty

blood

physiology

Radioimmunoassay

methods

statistics & numerical data

Sensitivity and Specificity

Sex Hormone-Binding Globulin

metabolism

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)