Dynamics of progesterone and estrogen receptor alpha in the ventromedial hypothalamus

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Sa, SI (Author) FMUP; Fonseca, BM (Author) FFUP

Journal

Title: Journal of Endocrinology

Vol. 233

Pages: 197-207

ISSN: 0022-0795

Publisher: BioScientifica Ltd.

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 10 Citations

Other information

Authenticus ID: P-00M-RKX

DOI: 10.1530/joe-16-0663

Abstract (EN): Cyclic fluctuations of estradiol and progesterone in females influence neuronal activity in the ventrolateral division of the ventromedial hypothalamic nucleus (VMNvl), through the activation of progesterone receptors (PRs) and estrogen receptors (ERs). The expression of ER and PR in the VMNvl is influenced by their cognate ligands and is a central upstream trigger in the pathway of VMNvl-dependent modulation of endocrine responses. By studying the role played by estradiol and progesterone in PR and ERa expression in the VMNvl along the estrous cycle and how the two receptors interact in the same neuron, we aim to evaluate the synergistic action of both ovarian hormones in the regulation of VMNvl activity. In animals at all phases of the estrous cycle, the number of VMN neurons expressing PR or ERa was estimated by stereological methods, and the percentage, and rostro-caudal distribution, of neurons simultaneously expressing both receptors was determined. The highest number of PR-immunoreactive neurons was seen at proestrus, and of ERa-immunoreactive neurons was seen at proestrus and metestrus. The ERa/PR co-localization is increased at caudal levels. Approximately half the neurons expressing PR co-express ERa, a proportion that stays constant along the estrous cycle. The percentage of ERa neurons co-expressing PR changes from 60% at proestrus to 40% at metestrus. Fluctuations in circulating ovarian hormone levels promote coordinated changes in PR and ERa expression and co-localization. This may be an important mechanism in the regulation of input relayed by the VMNvl, allowing a precise modulation of endocrine responses.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11