Pulsatile secretion of gonadotropins in early infancy.

In adults, luteinizing hormone (LH) and follicle stimulating hormone (FSH) are secreted in a pulsatile manner. Prior to puberty gonadotropin (GN) levels are low and show only small fluctuations. The following investigation was performed to elucidate the type of GN secretion in infants. LH and FSH were determined every 30 min over a period of 8 h in three different groups: Group 1:2 male and 2 female adults; Groups 2:2 male and 2 female prepubertal children; Group 3:3 male and 3 female infants, aged 6-12 weeks. Group 1 showed a clear pulsatile secretion of LH (4.5-23.5 mIU/ml [range]) and FSH (6.9-16.0 mIU/ml). Group 2 demonstrated a rather constant secretion of LH (less than 1.5-2.3 mIU/ml) and FSH (1.6-4.9 mIU/ml). Group 3: In male infants pulsatile secretion of LH (3.6-34.7 mIU/ml)--and to a lesser degree of FSH (1.8-4.6 mIU/ml)--were found. In female infants the pulsatile secretion of FSH (6.5-22.7 mIU/ml) was more pronounced than that of LH (less than 1.5-4.7 mIU/ml). The secretory pattern in early infancy is of a pulsatile type.