CHANGES IN THE ISOFORMS OF LUTEINIZING-HORMONE AND FOLLICLE-STIMULATING-HORMONE DURING PUBERTY IN NORMAL-CHILDREN

Concentrations of LH and FSH are known to increase during normal puber tal development, but changes in the isoforms of the gonadotropins at t his time have not been investigated in depth. We examined the median c harge of serum LH and FSH using agarose suspension electrophoresis in 81 normal children at pubertal stages I-V. In pubertal girls there wer e no significant (P > 0.05) differences in the median charge of LH, bu t there was a small (P = 0.05) shift to more acidic FSH isoforms betwe en pubertal stages I and IV. In boys there was a significant (P < 0.01 ) shift to more acidic isoforms for both LH and FSH by pubertal stage II. Further chan later in puberty. Except for LH at pubertal stage I, where the median charge was similar (P > 0.05) for both sexes, the med ian charge was more basic (P < 0.001) for both LH and FSH in girls com pared with boys at all five pubertal stages. The degree of charge hete rogeneity of FSH, estimated as the peak width at half the peak height, was significantly (P < 0.01) larger at pubertal stage I than at puber tal stages III-V in both boys and girls. The charge heterogeneity of L H was similar for all pubertal stages in both sexes. In conclusion, th ere were few qualitative changes in the gonadotropins during normal fe male puberty, whereas in the male there was a dramatic shift to more a cidic isoforms of LH and FSH early in puberty. This information may as sist our understanding of normal and pathological processes during pub erty and may be of clinical relevance in detecting the initiation of p uberty in boys.