On the mechanism of lactational anovulation in the rhesus monkey

Tamas Ordog, Ming D. Chen, Kevin T. O'Byrne, Jason R. Goldsmith, Martin A. Connaughton, Julane Hotchkiss, Ernst Knobil

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume274
Issue number4 37-4
StatePublished - Apr 1998
Externally publishedYes

Fingerprint

Anovulation
Pulse generators
Macaca mulatta
Gonadotropin-Releasing Hormone
Prolactin
Ovary
Periodicity
Haplorhini
Mothers
Pituitary Hormone-Releasing Hormones
Bromocriptine
Animals
Luteinizing Hormone
Ovulation
Progesterone
Estradiol
Nursing
Serum

Keywords

  • Bromocriptine
  • Gonadotropin-releasing hormone pulse generator
  • Multiunit electrical activity volley
  • Pregnancy
  • Prolactin

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Physiology
  • Physiology (medical)

Cite this

Ordog, T., Chen, M. D., O'Byrne, K. T., Goldsmith, J. R., Connaughton, M. A., Hotchkiss, J., & Knobil, E. (1998). On the mechanism of lactational anovulation in the rhesus monkey. American Journal of Physiology - Endocrinology and Metabolism, 274(4 37-4).

On the mechanism of lactational anovulation in the rhesus monkey. / Ordog, Tamas; Chen, Ming D.; O'Byrne, Kevin T.; Goldsmith, Jason R.; Connaughton, Martin A.; Hotchkiss, Julane; Knobil, Ernst.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 274, No. 4 37-4, 04.1998.

Research output: Contribution to journalArticle

Ordog, T, Chen, MD, O'Byrne, KT, Goldsmith, JR, Connaughton, MA, Hotchkiss, J & Knobil, E 1998, 'On the mechanism of lactational anovulation in the rhesus monkey', American Journal of Physiology - Endocrinology and Metabolism, vol. 274, no. 4 37-4.
Ordog T, Chen MD, O'Byrne KT, Goldsmith JR, Connaughton MA, Hotchkiss J et al. On the mechanism of lactational anovulation in the rhesus monkey. American Journal of Physiology - Endocrinology and Metabolism. 1998 Apr;274(4 37-4).
Ordog, Tamas ; Chen, Ming D. ; O'Byrne, Kevin T. ; Goldsmith, Jason R. ; Connaughton, Martin A. ; Hotchkiss, Julane ; Knobil, Ernst. / On the mechanism of lactational anovulation in the rhesus monkey. In: American Journal of Physiology - Endocrinology and Metabolism. 1998 ; Vol. 274, No. 4 37-4.
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