Abstract
We examined the effect of stroma-derived factors, hepatocyte growth factor（
HGF）and leptin, on morphological differentiation of bovine mammary epithelial
cells（BMEC）in collagen gel three-dimensional culture in vitro. BMEC
treated with HGF, but not leptin, formed duct-like organoids. The formation of
organoids by HGF was enhanced by treatment with a mixture of insulin, cortisol
and prolactin, while BMEC treated with the mixture alone did not produce
the organoid. In contrast, the formation of organoids by HGF was dosedependently
inhibited by simultaneous addition of leptin, regardless of the
presence or absence of the hormone mixture . These results suggest that
stroma-derived factors intricately regulate mammary epithelial morphogenesis.