Changes in growth hormone (GH) secretion and in growth during puberty.

During normal adolescent development in males testosterone induces the adolescent growth spurt, at least in part, by increasing GH production via an increase in the amplitude of the peaks of GH which are released, and not by increasing the frequency of GH pulses. Testosterone and estrogen administration at low or modest doses to individuals with the capacity to produce GH causes GH production and IGF-I levels to increase. Testosterone given to GHD patients does not increase either of these factors. In addition, there may be two actions for growth promotion by testosterone. One unequivocally results from an increase in GH production in the presence of low or modest levels of testosterone. A direct action on bone growth is probably present also, as reflected by the growth promoting effect of oxandrolone, a weak androgen, in boys with CDGA in the absence of increased GH production.