Serum gonadotrophins in young children.

LH and FSH were assayed in serum samples from children ranging from newborn to 13 years. In boys, LH was found in most samples up to 4 months of age, in many up to 10 months, but in only 38 percent between 1 and 8 years. In girls, it was found in only 29 percent of the samples under 1 year and the frequency and concentration changed little thereafter until 8-10 years. FSH was detected in all samples from boys up to 4 months and in most of those from girls up to 2 years. After these ages the frequency declined in each sex and there was little further change until 8-10 years. Between 1 and 8 years the proportion of samples containing either FSH or LH was similar for the two sexes, but whereas in boys high LH tended to be associated with high FSH, and vice versa, there was no such correlation in girls. The results are discussed in relation to gonadal development and steroid synthesis.