Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period

Finasteride treatment significantly reduces sperm transit time in the epididymis, sperm motility, and fertility parameters. A 30-day post-treatment recovery period was not enough to restore all parameters.

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Patrick Vianna Garcia, M.Sc., Mainara Ferreira Barbieri, B.Sc., Juliana Elaine Perobelli, M.Sc., Sílvio Roberto Consonni, M.Sc., Suzana de Fátima Paccola Mesquita, Ph.D., Wilma de Grava Kempinas, Ph.D., Luis Antonio Violin Pereira, M.D., Ph.D.

Vol 97, Issue 6 , Pages 1444-1451



To evaluate morphometric-stereological changes in the epididymal caput, sperm quality, and fertility parameters in rats treated with finasteride and after a 30-day post-treatment recovery period.


Experimental study in a research laboratory.


Reproductive biology research laboratory.


Male and female Sprague Dawley rats.


Treatment with finasteride (5 mg/kg/day) for 56 days followed by 30 days without treatment.

Main Outcome Measure(s):

Serum hormone analyses, morphometric-stereological and ultrastructural evaluation of the epididymal caput, sperm transit time, natural mating, in utero insemination, sperm membrane integrity, and fertility parameters.


Serum dihydrotestosterone levels in the finasteride group decreased by ∼40% compared with that of control rats. Ultrastructural analysis revealed significant reductions in several morphometric-stereological parameters of the epididymal caput. All parameters recovered significantly in the post-treatment period. There was no alteration in daily sperm production in the finasteride group. However, significant reductions in sperm transit time, motility, sperm membrane integrity, and fertility parameters were observed in rats treated with finasteride.


Treatment with finasteride caused morphometric-stereological and functional changes in the epididymis and in sperm function that led to a reduction in fertility parameters. A 30-day post-treatment recovery period was insufficient to restore normal sperm motility, sperm transit time, and some fertility parameters.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.