On the mechanism of lactational anovulation in the rhesus monkey
| Autor: | Ernst Knobil, Tamás Ördög, J. Hotchkiss, Kevin T. O'Byrne, Martin A. Connaughton, Jason R. Goldsmith, Ming Dao Chen |
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| Rok vydání: | 1998 |
| Předmět: |
endocrine system
medicine.medical_specialty Physiology Ovariectomy Endocrinology Diabetes and Metabolism media_common.quotation_subject Ovary Biology Gonadotropin-Releasing Hormone Anovulation Hormone Antagonists Estrus Physiology (medical) Internal medicine Lactation medicine Animals Ovulation Bromocriptine media_common Luteinizing Hormone medicine.disease Macaca mulatta Prolactin Animals Suckling Endocrinology medicine.anatomical_structure Ovariectomized rat Female Breast feeding Gonadotropins hormones hormone substitutes and hormone antagonists Hormone |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 274:E665-E676 |
| ISSN: | 1522-1555 0193-1849 |
| Popis: | The relative roles of infant suckling and of maternal prolactin (PRL) secretion in lactational anovulation were studied in ovary-intact and ovariectomized rhesus monkeys nursing young that had been removed from their natural mothers. Hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator activity was monitored electrophysiologically in freely behaving animals by radiotelemetry. Serum luteinizing hormone, PRL, estradiol, and progesterone were also measured. Suckling inhibited GnRH pulse generator activity and ovarian cyclicity in all ovary-intact females but had no such effect on the pulse generator in long-term ovariectomized animals. When PRL secretion was suppressed by daily bromocriptine administration, GnRH pulse generator activity remained significantly inhibited and ovulation was prevented in four monkeys (6 trials), whereas in two females (6 trials) a rapid increase in pulse generator frequency and the resumption of ovarian cyclicity were observed although suckling activity was maintained. One monkey displayed both response types. Although these results indicate that suckling per se is able to restrain GnRH pulse generator activity in the absence of PRL, they also suggest that the relative importance of these determinants is variable depending on factors that remain to be determined. The present study also confirms the permissive role of the ovary in the lactational suppression of GnRH pulse generator activity. |
| Databáze: | OpenAIRE |
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