Effects of oral buserelin on urinary LH secretion in male infants.

In recent years, several potent gonadotropin-releasing hormone (GnRH) analogues have become available for female contraception and one of them (buserelin) has been tested in lactating women. However, the possible effects on infants due to the transference of the analogue through breast milk have not been studied. The present work evaluated the effect of oral buserelin on urinary LH secretion in male infants. A total of 19 healthy full-term boys (aged 2-4 months) were included in the study. Infants received orally a single dose of a GnRH agonist mixed with breast milk. Urine samples were collected prior to, and 4-6 and 24 h after treatment for LH measurement. The results disclosed a significant increase in LH urine level in the sample taken 4-6 h after buserelin administration. Twenty-four hours after GnRH agonist ingestion, the LH level returned to baseline level. The present study demonstrated that GnRH analogue administered orally to infants escapes from gastrointestinal inactivation and induces a significant rise in LH levels 4-6 h after treatment.

PIP: An evaluation of the effects of oral buserelin on urinary luteinizing hormone (LH) secretion in 19 healthy breast-fed male infants 2-4 months of age indicated a need for further research on the effects of this agent on the hypothalamic-pituitary-gonad axis of infants. A single dose of 35 mcg of buserelin from a nasal spray was mixed with 20 ml of breast milk and fed to each infant, followed by a normal breast feed. A significant increase in urinary LH concentrations occurred between baseline (0.6 +or- 0.7 mUI/ml) and 4-6 hours after treatment (1.5 +or- 1.1 mUI/ml); however, 24 hours after agonist ingestion, LH levels returned to baseline levels. These findings suggest that a sufficient quantity of buserelin escapes from the gastrointestinal inactivation to stimulate the infant's pituitary, resulting in LH release. This phenomenon is probably due to an immaturity in the infants' gastrointestinal enzymes function.

GnRH agonist for postpartum contraception: biochemical, hormonal and endometrial effects.

OBJECTIVE: To determine whether GnRH agonist administration induces changes in biochemical, hormonal and endometrial parameters in breastfeeding women. DESIGN AND PATIENTS: Starting at 6 weeks postpartum, fully breastfeeding mothers began treatment with GnRH agonist, receiving 300 micrograms and 600 micrograms per day by nasal spray for 6 months. A third group of breastfeeding women who were users of IUDs served as controls. Eighteen biochemical analyses were quantified in serum. Blood samples were collected at 0, 3 and 6 months after treatment and endometrial biopsies were obtained at 0 and 6 months. No other method of contraception was employed. RESULTS: Interindividual and intergroup differences were observed in clinical chemistry. According to the hormonal levels and the histopathologic analysis, various grades of follicular activity were found in the treated groups. No pregnancies occurred. CONCLUSION: Because GnRH agonist treatment had no significant deleterious effects on the parameters studied, this treatment could represent a feasible and safe approach to postpartum contraception.