The Phenotype of the Aromatase Knockout Mouse Reveals Dietary Phytoestrogens Impact Significantly on Testis Function

Estrogen is synthesized in the testis, both in Leydig cells and seminiferous epithelium, and its importance in spermatogenesis is highlighted by the phenotype of the aromatase knockout (ArKO) mouse. These mice are unable to synthesize endogenous estrogens. The males develop postmeiotic defects by 18...

Full description

Saved in:
Bibliographic Details
Published in:Endocrinology (Philadelphia) 2002-08, Vol.143 (8), p.2913-2921
Main Authors: Robertson, Kirsten M, O’Donnell, Liza, Simpson, Evan R, Jones, Margaret E. E
Format: Article
Language:English
Subjects:
Aromatase
Biological effects
Diet
Epithelium
Estrogens
Follicle-stimulating hormone
Isoflavones
Leydig cells
Phenotypes
Phytoestrogens
Pituitary
Pituitary (anterior)
Pituitary-gonadal axis
Soybeans
Spermatogenesis
Synthesis
Testes
Xenoestrogens
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Estrogen is synthesized in the testis, both in Leydig cells and seminiferous epithelium, and its importance in spermatogenesis is highlighted by the phenotype of the aromatase knockout (ArKO) mouse. These mice are unable to synthesize endogenous estrogens. The males develop postmeiotic defects by 18 wk of age. We hypothesized that maintenance of spermatogenesis in younger animals may be mediated by exogenous estrogenic substances. Dietary soy meal, contained in almost all commercial rodent diets, provides a source of estrogenic isoflavones. We thus investigated spermatogenesis in wild-type and ArKO mice raised on a diet containing soy, compared with a soy-free diet, to elucidate the biological action of phytoestrogens on the testis. In ArKO mice, dietary phytoestrogens could partially prevent disruptions to spermatogenesis, in that they prevented the decline in germ cell numbers. They also seemed to maintain Sertoli cell function, and they blocked elevations in FSH. The impairment of spermatogenesis seen in soy-free ArKOs occurred in the absence of a decreased gonadotropic stimulus, suggesting that the effects of dietary phytoestrogens are independent of changes to the pituitary-gonadal axis. Our study highlights the importance of estrogen in spermatogenesis and shows that relatively low levels of dietary phytoestrogens have a biological effect in the testis.
ISSN:0013-7227
1945-7170
DOI:10.1210/endo.143.8.8957