Follicle-stimulating hormones in anterior pituitary glands from children and adults differ in relation to sex and age

Abstract

Follicle-stimulating hormone (FSH) in extracts of the anterior lobe of pituitaries, collected at autopsy from 13 boys, 21 girls, 17 men and 26 women, was measured in terms of biological activity (B) in vitro by the Sertoli cell aromatase bioassay, and in terms of immunological activity (I) by a radioimmunoassay. The highest concentration of FSH in the anterior lobe found by bioassay was in young girls, who had a mean value three to seven times higher than that in young and elderly men and women and nine times higher than that in young boys. The total amount of FSH in the pituitary found by bioassay and immunoassay was very much less in young boys than in all other groups. The B/I ratio of FSH was higher for all the 27 children below 10 years of age than for any of the 43 adults. This difference in B/I ratio of FSH in whole pituitary extracts persisted in fractions after electrophoretic separation. The mean B/I ratio for young girls was 1.26 times higher than that for young boys and 2.25 times higher than that for adults. Young and elderly men and women had almost identical B/I ratios. All extracts were analysed after electrophoresis and the median charge and charge homogeneity of FSH were estimated. The number of different forms of FSH in pituitary extracts from a child was at least 20-30, similar to that in an adult. In girls, the median charge of FSH was similar to that of young women and significantly less negative than in elderly women. The median charge of FSH in boys was more negative than in girls, but less negative than in both young and elderly men. After treatment of pituitary extracts with neuraminidase, the median charge of FSH in infants was significantly more negative than that in adults. This, together with the differences in B/I ratios between children and adults, indicates a change at puberty in the molecular structure of FSH from juvenile to adult forms of the hormone.