Measurement of immunologically reactive follicle stimulating hormone in serum of normal male children and adults

Using a radio immunoassay serum, FSH concentrations have been determined in 97 normal male children between the ages of 5 and 18 years, in 30 normal adult males between 25 and 45 years, and in 9 adult patients who were sexually infantile, presumably because of deficient gonadotrop in secretion by the pituitary. FSH reactive material was found in all serums. In normal children serum FSH concentrations begin increasing shortly after 9.0 years of age from the low levels found in early childhood. By the age of 13 years the mean FSH determination was comparable to that of normal adults. When correlated with various stages of sexual development (1 through 5), the mean FSH concentrations found in the serums of individuals in stages 1, 2, and 3 differed significantly from each other. However, mean levels for the individuals in groups 3, 4, and 5 did not differ significantly. There was a low degree of correlation between serum FSH concentration and the excretion of urinary 17-ketosteroids. The values of immunologic FSH reported may have no specific correlation with biologically active FSH in serum, and all results are interpretable only in comparison of one group of values against another. The determination of absolute values of FSH in serum will be possible only when there is an adequately defined standard for serum and commonly available antigen and antiserum. Only then will it be possible to compare biologic and immunologically reactive FSH in sera.