FIGURE 3.
The mammary gland of the virgin PR-B:OE bigenic exhibits an increased number of nascent alveolar buds compared to sibling control glands at diestrus. (a) and (b) show whole mounts of control and PR-B:OE inguinal mammary glands respectively; LN denotes lymph node (a structural reference marker). (c) and (d) are higher magnifications of specific regions shown in (a) and (b) respectively. Note that the structural complexity of the ductal network is markedly increased in the PR-B:OE mammary gland (d) compared to the control gland (c). White arrowheads indicate the location of nascent alveolar buds. (e) and (f) show higher magnifications of representative ductal regions in the control and PR-B:OE mammary gland respectively. Note the marked increased number of alveolar buds (white arrowheads) in the PR-B:OE mammary gland (f) compared to control (e). Scale bar in (a), (c), and (e) apply to (b), (d) and (f) respectively.