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Patterns of pulsatile luteinizing hormone secretion before and during the onset of puberty in boys: a study using an
F C Wu1, G E Butler, C J Kelnar
1Medical Research Council Reproductive Biology and Human Genetics Unit, Edinburgh, Scotland, United Kingdom.
Insights
Pulsatile secretion of luteinizing hormone (LH) increases significantly in frequency and amplitude around puberty onset in boys. This study tracks LH secretion patterns to understand pubertal development and pituitary-gonadal function.
Area of Science:
- Endocrinology
- Pediatric Endocrinology
- Reproductive Endocrinology
Background:
- Spontaneous pulsatile secretion of gonadotropins is crucial for pubertal development.
- Understanding the dynamics of luteinizing hormone (LH) and gonadotropin-releasing hormone (GnRH) secretion is key to assessing pubertal progression.
Purpose of the Study:
- To investigate the changes in spontaneous pulsatile LH secretion during the onset of puberty in boys.
- To correlate LH secretion patterns with pituitary and gonadal responsiveness.
Main Methods:
- Nocturnal plasma LH levels were measured using immunoradiometric assay in 30 boys aged 5.6-16.8 years.
- Blood samples were collected at 10-20 minute intervals from 20:00 to 08:00.
- LH pulse analysis was performed using a computerized peak detection algorithm, alongside LHRH challenges and testosterone measurements.
Main Results:
- LH pulse frequency significantly increased from prepubertal (0.93/12h) to peripubertal (4.55/12h) and pubertal (6.20/12h) stages.
- LH pulse amplitude remained low in prepubertal/peripubertal boys, significantly increasing in pubertal boys (2.02 U/L).
- Pituitary responsiveness to LHRH and testosterone levels showed significant increases with pubertal progression.
Conclusions:
- Pulsatile LH secretion demonstrates a distinct pattern of increase in frequency and amplitude during male puberty.
- These findings provide insights into the neuroendocrine regulation of puberty and can aid in diagnosing developmental abnormalities.
Abstract:
To study spontaneous pulsatile LHRH/LH secretion around the onset of puberty, nocturnal plasma LH was measured by means of a highly sensitive immunoradiometric assay in 30 boys (aged 5.6-16.8 yr) investigated for potential problems with growth and/or development. Blood was withdrawn at 10- to 20-min intervals from 2000-0800 h. Pulse analysis was accomplished by a computerized peak detection algorithm. Pituitary and gonadal responsiveness was assessed by a standard exogenous LHRH challenge and testosterone. Subsequent clinical progress was monitored for a mean duration of 2.08 +/- 0.16 yr and used as the basis for classifying patients retrospectively into three groups: 1) prepubertal (n = 14), 2) peripubertal (n = 11), and 3) pubertal (n = 5). LH pulses were undetectable in 9 and present in 5 prepubertal subjects, the youngest of whom was aged 7.3 yr. In peripubertal and pubertal individuals, 2-7 LH pulses/12 h were detectable. LH pulses were detectable before sleep by midpuberty (Tanner stage 3). There was a highly significant (P less than 0.0001) increase in LH/LHRH pulse frequency from 0.93 +/- 0.38 to 4.55 +/- 0.43/12 h (mean +/- SEM) between the prepubertal and peripubertal groups and a further increase to 6.20 +/- 0.37/12 h in the pubertal group. LH pulse amplitude remained under 1.0 U/L in both the prepubertal and peripubertal groups and only increased significantly to 2.02 +/- 0.17 U/L in pubertal boys. Response to LHRH increased significantly between the prepubertal (2.47 +/- 0.49 U/L) and peripubertal (6.53 +/- 2.02 U/L) patients. T increased significantly at each stage, with the greatest rise between the peripubertal and pubertal stages.(ABSTRACT TRUNCATED AT 250 WORDS)