Longitudinal study of testosterone and luteinizing hormone (LH) in relation to spermarche, pubic hair, height and sitting height in normal boys.

In a 7-year longitudinal study of 40 normal boys, initially aged 8.6-11.7 years, 24-h urine samples were collected every 3 months and analysed for LH and testosterone as well as for the presence of spermatozoa (spermaturia). Spermarche (onset of the release of spermatozoa) was estimated on the basis of age at the first observed spermaturia. Physical examination, including measurements of height and sitting height and staging of pubic hair (Tanner stage) was performed every 6 months. Spermarche occurred early in puberty when the median pubic hair stage was 2.5. Urinary testosterone did not reach maximum levels until approximately 2 years after spermarche. Peak height velocity occurred when urinary testosterone levels were low, 1-2 years before adult levels of testosterone were attained. Our results support the proposition that low levels of testosterone have a predominantly growth-promoting effect, whilst higher concentrations have an inhibitory effect on height spurt.