Mammary gland tissue distribution of PTN mRNA.

(A) In situ hybridization (ISH) with PTN mRNA antisense and sense probes. Red squares indicate the areas shown at higher magnification. Scale Bars  = 25 μm and 100 μm respectively. Red arrowheads indicate PTN mRNA expression in mammary epithelial cells. (B) Northern blot for PTN mRNA in virgin mammary glands fractionated into epithelial and stromal cells.