Fig. 1. ECM affects morphology, ß-casein and connexin expression by CID-9 cells on day 6 of culture. (A) Morphology of CID-9 cells cultured in differentiation medium on (a) plastic, (b) EHS-drip and (c) EHS-matrix. (B) Northern blot analysis of ß-casein, Cx43 and Cx26 by cells on plastic (Pl), EHS-drip (Ed) and EHS-matrix (Ec). ß-Casein expression was only evident in the presence (+) of prolactin (Prl) and not in its absence (-), whereas Cx43 was significantly (P<0.001) downregulated in cells in differentiation medium on Ec compared with cells on Pl or Ed. Cx26 was not downregulated in cells in differentiation medium on Ec compared with those on Pl. 28S rRNA demonstrates equal loading.