Circulating FSH, LH, GH, testosterone, TSH, T3, T4, prolactin and insulin in boys during puberty.

: The dynamics of the serum FSH, LH, GH, T, TSH, T3, T4, prolactin (PRL) and insulin levels was studied in 50 healthy boys aged between 8 and 18 years, in correlation with the development of the gonad (sexualization) assessed through the five-stage classification (G I-G V) proposed by Tanner. The results reveal the role of gonadotropins (especially LH) and testosterone in the growth and development of the child and especially in the sexualization process through a progressive increase from stage GI to GV. In stage GV, LH and T reach the values of an adult. GH shows a peak during the maximum height and weight increase. Thyroid hormones T3 and T4 also prove their role, showing higher values in the span of accelerated growth and significantly lower levels in the final stages of puberty (G IV-GV). The dynamics of prolactin secretion during the pubertal development shows (in all the 5 stages of sexualization) close serum levels. Serum insulin level also shows a progressive increase all along the pubertal years (from G I to G V).