Urine gonadotropin and testosterone levels in male very-low-birthweight infants.
OBJECTIVE
The postnatal activation of the hypothalamic-pituitary-gonadal axis is more exaggerated in preterm than in full-term-born infants, and may be important for reproductive function. Our objective was to investigate this activation of the hypothalamic-pituitary-gonadal axis in male very-low-birthweight (VLBW) infants.


METHODS
Twenty-one VLBW boys (gestational age 26.0-30.0 weeks), participating in the NIRTURE trial, were included. Gonadotropin and testosterone levels were measured in serial urine samples collected at 1 and 4 weeks' postnatal age, at 32 weeks' postmenstrual age, at expected date of delivery and at the corrected age of 3 and 6 months.


RESULTS
Longitudinal analysis shows that after birth LH and FSH levels peak at a mean postnatal age of 1-4 weeks (mean postmenstrual age of 30-32 weeks) and decrease until 38 weeks' postnatal age (corrected age of 6 months). Testosterone levels decrease with increasing age, and this decrease is faster in infants receiving early insulin therapy.


CONCLUSIONS
Serial urine sampling for measurement of gonadotropin and testosterone levels provides accurate information about the postnatal activation of the hypothalamic-pituitary-gonadal axis in VLBW boys. FSH and LH levels peak at 1-4 weeks of age. Insulin treatment causes faster decrease in testosterone levels.
Department of Pediatrics, Albert Schweitzer Hospital, Dordrecht, The Netherlands.
M
M
de Jong
J
J
Rotteveel
A C
AC
Heijboer
A
A
Cranendonk
J W R
JW
Twisk
M M
MM
van Weissenbruch
D005865:Gestational Age; D006062:Gonadotropins / Q000652:urine*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight / Q000378:metabolism*; D008297:Male; D013739:Testosterone / Q000652:urine*; D013997:Time Factors
D006062:Gonadotropins; D013739:Testosterone