Japanese Journal of Veterinary Research;Volume 48, Number 4

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Relationship among growth, steroid production and immunolocalization of transforming growth factor-β1 in the normally developing mouse follicles cultured in vitro

BISHONGA, Christopher;TAKAHASHI, Yoshiyuki;KATAGIRI, Seiji;NAGANO, Masashi;ISHIKAWA, Akiko

Permalink : http://hdl.handle.net/2115/2857
JaLCDOI : 10.14943/jjvr.48.4.169
KEYWORDS : estradiol;follicle culture;granulosa cells;mouse

Abstract

This study examined the relationship among growth, steroid production and transforming growth factor-β1 (TGF-β1) immunolocalization in the mouse follicles cultured in vitro to evaluate the hypothesis that normally developing follicles should express TGF-β1 in the granulosa cells around the time of antrum formation. Preantral follicles with 151-175μm (large category) and 125-150 μm (small category) of initial diameters were used as models for normal and retarded follicles, respectively. Growth rate and timing of antrum formation in both categories were comparable to those of in-vivo grown follicles. At the time of antrum formation, follicular diameters were similar between the two follicle categories; however, antral follicles from the large category showed larger number of granulosa cells, higher estradiol production and proportion of follicles with TGF-β1 positive granulosa cells. Two days after antrum formation, there were no differences in the number of granulosa cells and the proportions of follicles with TGF-β1 positive granulosa or theca cells between the two categories. Temporal association in large follicles between the increase in estradiol production and proportion of follicles with TGF-β1 positive granulosa cells at the time of antrum formation supports our hypothesis. Furthermore, this study demonstrated the usefulness of the follicle culture system in the investigations of follicular physiology.

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