Estrogen Signaling in Male Reproductive Physiology

Estrogens, traditionally viewed as female hormones, are now recognised as critical regulators of male reproductive function. In the testis, local synthesis of 17β-estradiol by aromatase in Leydig cells and specific germ-cell populations ensures paracrine and autocrine control of spermatogenesis, Sertoli cell support and fluid homeostasis in efferent ductules. Two classical nuclear receptors, ERα and ERβ, mediate genomic actions by modulating gene transcription, while a membrane-associated G protein-coupled estrogen receptor (GPER) elicits rapid signalling cascades that influence cell proliferation, apoptosis and steroidogenesis. Estrogen signalling contributes to the fine tuning of the hypothalamus–pituitary–gonadal axis, regulates ion transport and fluid reabsorption in the epididymis, and supports sperm maturation and motility. Disruption of these pathways, whether through genetic ablation of receptors or exposure to exogenous oestrogenic compounds, leads to impaired tubule architecture, altered steroid output and reduced fertility. The global rise in endocrine-disrupting chemicals and increasing male infertility rates underscore the practical imperative to clarify estrogen’s multifaceted roles, offering potential routes to novel diagnostics and therapeutics in reproductive medicine.

Research from Nature Portfolio

Recent work examining testes from individuals receiving long-term estradiol therapy has revealed profound morphological changes under sustained hyperestrogenic conditions. Treated samples exhibited a significant reduction in seminiferous tubule diameter and pronounced fatty degeneration of the interstitial compartment. Collagen deposition in the extracellular matrix surrounding tubules was markedly increased, correlating with disrupted spermatogenesis and persistence of only early germ-cell stages. Expression of ERα was diminished in Sertoli cells, while both Sertoli and Leydig cells displayed structural alterations and aberrant glycoprotein accumulation. These findings illustrate how elevated estradiol levels can compromise testicular microenvironment, informing our understanding of hormone-driven testicular disorders and guiding hormone-modulating treatment strategies.

Estrogen Signaling in Male Reproductive Physiology publication trend

The graph below shows the total number of articles in estrogen signaling in male reproductive physiology across all publications each year (not limited to Nature Index journals).

Technical terms

17β-Estradiol: The most potent natural estrogen synthesised by aromatase from androgens.

Aromatase: Cytochrome P450 enzyme that converts testosterone to estradiol in testes and peripheral tissues.

ERα (Estrogen Receptor α): Nuclear receptor mediating genomic estrogen responses critical for ductule morphology and fertility.

GPER (G Protein-Coupled Estrogen Receptor): Membrane-associated receptor that transduces rapid, non-genomic oestrogen signals.

Spermatogenesis: The multistage process of germ-cell proliferation, meiosis and differentiation into mature spermatozoa.

Efferent Ductules: Channels connecting testicular rete to the head of the epididymis, vital for luminal fluid reabsorption under estrogen control.

References

1. Functions of Steroid Hormones in the Male Reproductive Tract as Revealed by Mouse Models. International Journal of Molecular Sciences (2023).
2. Steroid hormone signaling: multifaceted support of testicular function. Frontiers in Cell and Developmental Biology (2024).
3. Effects of Elevated β-Estradiol Levels on the Functional Morphology of the Testis - New Insights. Scientific Reports (2017).
4. Role of Estrogen Receptors and G Protein-Coupled Estrogen Receptor in Regulation of Hypothalamus–Pituitary–Testis Axis and Spermatogenesis. Frontiers in Endocrinology (2014).
5. Of Oestrogens and Sperm: A Review of the Roles of Oestrogens and Oestrogen Receptors in Male Reproduction. International Journal of Molecular Sciences (2017).
6. Aromatase expression and role of estrogens in male gonad : a review. Reproductive Biology and Endocrinology (2003).