Fig. 7. Myocardial differentiation in cultured secondary heart field is inhibited
by noggin. All the panels show secondary heart fields cultured for 24 hours,
incubated with BrdU for 1 hour and then doubly stained to show
fluorescein-labeled antiBrdU (green) and rhodamine-labeled MF-20 (red). Medium
was conditioned as indicated above the panels: A,E, unconditioned medium; B,F
secondary heart field-conditioned medium; C,G, pharyngeal
endoderm/ectoderm-conditioned medium; and D,H, myocardium-conditioned medium.
The heart fields shown in the lower panels were cultured in the conditioned
medium indicated with 15 µg/ml noggin protein added. Noggin appears to have
decreased myocardial differentiation and increased proliferation, except in
the secondary heart field cultured in secondary heart field conditioned medium
(B,F). The endoderm/ectoderm conditioned medium caused increased proliferation
in both the absence (C) and presence (G) of noggin.
