Follicle-stimulating hormone is a pituitary hormone that acts on the follicle cells of the ovary to trigger the synthesis of cyclic amp, which stimulates various metabolic changes. fsh normally has no effect on cardiac muscle cells. however, when ovarian follicle cells and cardiac muscle cells are grown together in mixed culture, a number of the cardiac muscle cells are seen to contract following addition of fsh to the medium. how might this observation be explained?