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Neonatal exposure to coumestrol, a phytoestrogen, does not alter spermatogenic potential in rats
C A Awoniyi1, D Roberts, V Chandrashekar
1Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver 80262, USA. caleb.awoniyi@uchsc.edu
Insights
Neonatal exposure to coumestrol, a phytoestrogen, did not affect adult male rat reproductive organs or sperm production. However, it did increase follicle-stimulating hormone beta (FSH beta) mRNA levels without impacting reproductive potential.
Area of Science:
- Endocrinology
- Reproductive Biology
- Toxicology
Background:
- Phytoestrogens are plant-derived compounds with estrogenic activity.
- Neonatal exposure to endocrine disruptors can have long-term effects on reproductive health.
- Coumestrol is a prominent phytoestrogen found in legumes.
Purpose of the Study:
- To investigate the impact of early-life coumestrol exposure on male rat reproductive function in adulthood.
- To assess potential alterations in hormone levels, organ weights, sperm counts, and gene expression.
Main Methods:
- Neonatal male rats received daily injections of coumestrol or a control (DMSO) for the first five days of life.
- Reproductive organs, pituitary, and blood were collected at 60 days of age.
- Hormone levels (testosterone, LH, FSH) and mRNA expression of LH beta and FSH beta were quantified.
Main Results:
- Coumestrol exposure did not alter testes or sex accessory organ weights, or sperm counts.
- Serum levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) remained unchanged.
- While LH beta mRNA levels were unaffected, FSH beta mRNA levels increased by 37% in coumestrol-treated rats.
Conclusions:
- Neonatal coumestrol exposure does not impair male rat reproductive organ structure or spermatogenic potential.
- Increased FSH beta mRNA expression did not translate to negative reproductive outcomes.
- Early-life exposure to this phytoestrogen appears to be safe for male reproductive development.
Abstract:
The objective of this study was to determine the effects of neonatal exposure to phytoestrogens on male reproductive function as adults. Male rats were injected either with 100 micrograms coumestrol or DMSO (controls) daily during their first 5 d of life. Pituitary gland, testes, sex accessory organs, and blood were collected on d 60 of life. Serum testosterone, LH, and FSH levels were determined by RIA. Levels of steady-state mRNA for gonadotrophin subunits (LH beta and FSH beta were determined by Northern blot analysis and quantified by a scanning densitometer. Coumestrol had no effect on weights of testes and sex accessory organs, or sperm count. Similarly, there were no significant differences among serum concentrations of testosterone, LH beta and FSH of coumestrol-treated rats and those of controls. Whereas steady state levels of LH beta mRNA in coumestrol-treated rats did not differ from those of controls, steady state levels of FSH beta mRNA increased (37%) in treated animals. However, the augmented FSH beta mRNA expression in coumestrol-treated rats did not negatively affect reproductive potential in male rats. We conclude that neonatal exposure to coumestrol does not alter reproductive organ structure or spermatogenic potential in male rats.