Serum testosterone levels and growth velocity in healthy boys

• Background: Androgens and their conversion to estrogens by aromatase have a major role in the pubertal growth but there is little knowledge of the details of the relationship between testosterone levels and the phases of the pubertal growth. Objective: To study 24 h profiles of serum testosterone in boys admitted for short or tall stature or participating as health subjects at Queen Silvia Children’s Hospital in relation to their growth. Methods: Inclusion criteria to the study were birth weight and length above -2 SDS, gestational age 37-42 weeks, prepubertal length and weight within ±3 SDS, normal 24 h growth hormone (GH) profile and no GH treatment. Assent was obtained from the boys and informed consent from parents for future analysis of the data. This resulted in 26 boys and 41 profiles of 24 h serum testosterone. Serum testosterone concentrations were determined in duplicate by a modified radioimmunoassay (Spectria testosterone; Orion diagnostica, Espoo, Finland). Lower assay sensitivity was 0.03 nmol/L. A 6th grade polynomial was fitted to each child´s growth data and growth velocity and age of peak height velocity (PHV) was calculated. Results: A positive correlation between morning testosterone and increase in growth velocity was found (r2=0.57). In a simple Effect-max model the 50% of increase in growth velocity from prepubertal growth to PHV was observed at a morning testosterone level of 2.8 ±0.9 nmol/L. All boys (n=9) with morning testosterone levels above 10 nmol/L had reached above 96% of their pubertal growth capacity up to PHV. The morning testosterone median of the 6 boys who were investigated at PHV ±3 months was 11.4 nmol/L (6.5-12.6). Conclusions: 1) Morning testosterone levels of 1.9-3.7 nmol/L are associated with a 50% of increase in growth velocity from prepubertal growth to PHV in healthy boys. 2) Morning testosterone levels above 10 nmol/L are seen close to PHV.

Ämnesord

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

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

Nyckelord

Testosteron

boys

growth

Publikations- och innehållstyp

vet (ämneskategori)

kon (ämneskategori)