title: Dynamics of bioactive luteinizing hormone-human chorionic gonadotropin during the first 7 days of life.
abstract: Serum luteinizing hormone-human chorionic gonadotropin bioactivity (B-LH) was measured daily in seven male and four female full-term newborns during the first 7 days of life. The B-LH levels were elevated in both sexes during the 1st day of life; subsequently, values decreased in both sexes. In males, they reached a nadir on the 4th day of life. A gradual secondary rise was then observed with B-LH levels on the 7th day significantly higher than on day 4 (p less than 0.025). By contrast, the B-LH levels in the females continued a gradual decline to levels significantly lower on day 7 as compared to day 4 (p less than 0.05). To determine whether pulsatile B-LH secretion occurs in newborns, serum concentrations were measured every 20 min for 2 h in eight male and seven female full-term neonates on the 7th day of life. Pulsatile secretion of B-LH was detected in six males and six females. This study demonstrates that pulsatility of gonadotropin secretion is characteristic of neonates as early as 7 days of life and that there is a dichotomy between the levels of B-LH in males and females; levels in females decline progressively from day 1 through 7, whereas in males, a nadir is reached on day 4 with a secondary rise developing thereafter. This male sex-specific rise is presumably the drive responsible for the characteristic postnatal increase in testosterone which peaks at 1 to 2 months of age.
authors.affiliation: Department of Pediatrics, Facultad de Medicina Universidad del Valle, Cali, Colombia.
authors.forename: M
authors.initials: M
authors.lastname: Danon
authors.forename: O
authors.initials: O
authors.lastname: Velez
authors.forename: T
authors.initials: T
authors.lastname: Ostrea
authors.forename: J D
authors.initials: JD
authors.lastname: Crawford
authors.forename: I Z
authors.initials: IZ
authors.lastname: Beitins
mesh_terms: D000367:Age Factors; D006063:Chorionic Gonadotropin / Q000097:blood* / Q000502:physiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007986:Luteinizing Hormone / Q000097:blood* / Q000502:physiology; D008297:Male; D012737:Sex Factors
chemical_list: D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone