Relaxin-3 stimulates the hypothalamic-pituitary-gonadal axis
B M McGowan1, S A Stanley, J Donovan
1Dept. of Investigative Medicine, Division of Investigative Science, Imperial College London, Hammersmith Campus, Du Cane Road, London, UK.
Summary
Relaxin-3 stimulates the reproductive axis by increasing gonadotropin-releasing hormone (GnRH) release. This neuropeptide may link energy balance and reproductive function in the hypothalamus.
Area of Science:
- Neuroendocrinology
- Reproductive Biology
- Metabolic Regulation
Background:
- The hypothalamus regulates energy homeostasis and reproduction.
- Relaxin-3, an orexigenic neuropeptide, acts via RXFP3 and potentially RXFP1 receptors.
- Relaxin-3, its receptors, and GnRH neurons are co-localized in the paraventricular nucleus.
Purpose of the Study:
- To investigate the role of relaxin-3 in regulating the hypothalamo-pituitary-gonadal (HPG) axis.
- To determine if relaxin-3 influences reproductive function.
Main Methods:
- Administered human relaxin-3 (H3) intracerebroventricularly and intraparaventricularly in male Wistar rats.
- Utilized a peripheral GnRH antagonist to block effects.
- Stimulated GnRH release from hypothalamic explants and GT(1)-7 cells in vitro.
Main Results:
- H3 administration significantly increased plasma luteinizing hormone (LH) levels.
- The LH increase was blocked by GnRH antagonist pretreatment.
- H3 dose-dependently stimulated GnRH release from hypothalamic cells but not pituitary hormones.
Conclusions:
- Relaxin-3 stimulates the HPG axis, likely through hypothalamic GnRH neurons.
- Relaxin-3 may serve as a central signal connecting nutritional status with reproductive function.
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