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Testicular responsiveness to hCG during infancy measured by salivary testosterone
1Children's Hospital, University of Helsinki, Finland.
Insights
Human chorionic gonadotropin (hCG) stimulates testosterone production in male infants, indicating gonadotropin-mediated postnatal testicular activation. Salivary testosterone measurements offer a non-invasive method for assessing infant gonadal function.
Area of Science:
- Pediatric Endocrinology
- Reproductive Biology
- Hormone Research
Background:
- Postnatal testicular activation is crucial for male development.
- The role of gonadotropins in early testosterone production requires further elucidation.
Purpose of the Study:
- To investigate the role of gonadotropins in postnatal testicular activation.
- To assess testosterone responsiveness to human chorionic gonadotropin (hCG) in male infants.
Main Methods:
- Eleven male infants (5-180 days) received hCG injection; serum and salivary testosterone were measured for 7 days.
- Results were compared to 8 older prepubertal boys using the same protocol.
- Basal and stimulated testosterone levels were analyzed.
Main Results:
- Infants exhibited significantly higher basal serum testosterone than prepubertal boys.
- Both groups showed significant testosterone response to hCG stimulation (p < 0.001).
- Stimulated serum testosterone concentrations were higher in infants than prepubertal boys (p < 0.001).
Conclusions:
- hCG significantly stimulates testicular testosterone production in male infants.
- Postnatal increases in serum testosterone are likely gonadotropin-mediated.
- Salivary testosterone measurements provide a viable, non-invasive method for assessing pediatric gonadal function.
Abstract:
To investigate the role of gonadotropins in postnatal testicular activation, testosterone responsiveness to human chorionic gonadotropin was studied in 11 male infants (aged 5-180 days). The boys were given a single im injection of 5000 IU/1.7m2 hCG, and serum and salivary testosterone responses were then measured for 7 days. The results were compared with the serum testosterone responses of 8 older prepubertal boys (aged 1.7-10.4 years) studied with the same protocol. The mean (+/- SEM) basal serum testosterone levels were 2.67 +/- 1.27 nmol/l in the infants and 0.09 +/- 0.02 nmol/l in the prepubertal boys (p less than 0.05). Both groups gave a significant response to hCG stimulation (p less than 0.001, ANOVA, one-way). The stimulated concentrations of serum testosterone were higher in the infants than in the prepubertal boys (p less than 0.001). The mean basal level of salivary testosterone was 30.5 +/- 7.0 and the mean maximal level was 97 +/- 10.3 pmol/l in the infants (p less than 0.001). No age-related changes were observed in either basal or hCG-stimulated levels. In infants the mean (+/- SEM) maximal hCG-stimulated increase was 25 +/- 10-fold in serum and 8 +/- 4-fold in saliva (p = 0.13). A clear stimulatory effect of hCG on testicular testosterone production was found, suggesting that the postnatal increase in serum testosterone concentration in male infants is gonadotropin-mediated. Salivary testosterone concentrations can be increased by hCG, indicating that measurements of salivary testosterone may provide an optional, non-invasive method for assessing gonadal function in children.