P. Xia et al., EXPRESSION OF INSULIN-LIKE GROWTH-FACTORS IN 2 BOVINE OVIDUCTAL CULTURES EMPLOYED FOR EMBRYO COCULTURE, Journal of Endocrinology, 149(1), 1996, pp. 41-53
We have investigated the patterns of expression and cellular localizat
ion of polypeptides and mRNAs encoding TGF-I and IGF-II in intact bovi
ne oviduct and two bovine oviductal primary cultures (monolayers and v
esicles) which are utilized for supporting development in vitro. IGF-I
and IGF-II polypeptides were localized by immunocytochemistry in inta
ct oviduct and in both primary cultures for an 8-day culture interval,
but IGF-II polypeptide displayed a more restricted distribution in da
y 8 monolayer cultures. IGF-I and IGF-II mRNAs were localized in both
oviductal cell cultures as assessed by in sih hybridization. We were u
nable to detect IGF-I and IGF-II mRNAs in intact oviduct by in situ hy
bridization; however, transcripts encoding IGF-I and IGF-II mRNAs were
detected in intact oviduct cell preparations and all primary culture
samples by reverse transcription-PCR methods. The origin and phenotypi
c stability of these cultures was assessed by immunostaining with anti
bodies raised against vimentin (mesenchymal cell marker) and cytokerat
in (epithelial cell marker). Over the culture period, the proportion o
f vimentin-immunoreactive cells increased in the monolayer cultures bu
t remained at a low level in the vesicle cultures which were predomina
ntly composed of cytokeratin-positive cells. The results suggest that
oviductal cell co-culture may facilitate early mammalian development,
in part, by the establishment of paracrine growth factor circuits.