Pulsatile Secretory Pattern of Gonadotropins in Infants

In adult males and females luteinizing hormone (LH) and to a lesser degree follicle stumulating hormone (FSH) are secreted in a pulsatile fashion: an abrupt rise of the hormone is followed by a slower decline during 1 to 3 hours. Prior to puberty gonadotropin (GN) levels are low and show little fluctuation. Recently high GN levels as well as gonadal activity were demonstrate in infants. The following examination was carried out to elucidate the type of GN secretion in early infancy. LH and FSH were determined every 30 minutes over a period of 8 hours in three diffenrent groups: Group 1: 2 male and female adults, Group 2: 2 male and female prepubertal children, Group 3: 3 male and 3 female infants, age 6-12 weeks. Group 1 showed a clear pulsatile secretion of LH (4,5-23,5 mIU/ml (range)) and FSH(6,0-16,0 mIU/ml) Group 2 demonstrated a rather constant secretion of LH (1,5-2,3 mIU/ml) and FSH (1,6-4,9 mIU/ml). Group 3: In male infants we found a pulsatile secretion of LH (3,6-34,7 mIU/ml) and to a lesser degree of FSH (1,8-4,6 mIU/ml). In female infants the pulsatile secretion was more pronounced in FSH (6,5-22,7 mIU/ml) than in LH (1,5-4,7 mIU/ml). In conclusion, the secretory pattern in early infancy shows a pulsatile GN pattern of an infant type.