Studies in human fetal endocrinology: II. LH and FSH content and concentration in the pituitary

The luteinizing hormone (LH) and follicle-stimulating hormone (FSH) content and concentration in 67 whole fetal pituitary glands have been determined by specific radioimmunoassay. A distinct pattern was observed for LH and FSH related to fetal age and sex. In the female, a mid-gestation peak of LH and FSH was found, followed by a rapid and significant decline in both gonadotropins. There was a secondary increase in the content but not the concentration from 24 weeks' gestation to term. In the male, LH and FSH content continued to increase throughout gestation. However, the rise after 20 weeks' gestation is related to the increasing pituitary weight. These data are discussed in relation to the endocrine status of the fetal gonad and hypothalamus at comparable gestational ages.