| Autor: |
Ilingworth, P.J., Seaton, J.E.V., McKinlay, C., Reid-Thomas, V., McNeilly, A.S. |
| Zdroj: |
Human Reproduction; Jul1995, Vol. 10 Issue 7, p1671-1677, 7p |
| Abstrakt: |
The object of the study was to investigate the effect on gonadotrophin secretion of a small increase in oestradiol concentration. A total of 13 fully breast-feeding women (12 weeks post-partum) underwent serial blood sampling at 10 min intervals for 12 h on 2 different days; day 1 untreated and day 5 after 3 days of treatment with transcutaneous oestradiol (100 μg/day). On both days bolus gonadotrophin-releasing hormone (GnRH; 10 μg i.v.) was given after a 10 h baseline period. In six of the subjects, a naloxone infusion was administered during the second study day. Application of transdermal oestradiol raised the oestradiol concentration within the normal follicular phase range. The mean luteinizing hormone (LH) concentration on day 5 was found to be significantly lower than that on day 1 ( < 0.05). The LH response to GnRH was, however, significantly higher on day 5 than day 1 ( < 0.001). The mean follicle stimulating hormone (FSH) concentration on day 5 was also significantly lower than that on day 1 ( < 0.01), while the peak concentration after GnRH was unchanged. When the opioid antagonist naloxone was infused after oestradiol treatment, the subjects with low pre-study oestradiol concentrations exhibited no effect on LH concentration, while in the subjects with higher oestradiol concentrations the LH concentration was increased. It was concluded that the administration of small doses of oestradiol caused a significant fall in gonadotrophin concentration in breast-feeding women. This indicates a heightened sensitivity to the negative feedback effect of oestradiol on GnRH release from the hypothalamus, since the pituitary response to GnRH was unaltered. Further studies are required to investigate the possibility that these doses of oestrogen may have some clinical value in inhibiting ovulation after delivery. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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