Updated project metadata. In the ovary, proliferation and differentiation of granulosa cells (GCs) drive the growth of follicles. This is, in part, dependent on gonadotropins. Our immunohistochemical studies provided hints of mitochondrial biogenesis and intracellular redistribution in GCs of growing follicles. A cellular model, human KGN cells (granulosa cell tumor cells, derived from growing follicles) was used to study aspects of mitochondrial dynamics. To elevate cAMP and thereby mimic gonadotropin actions, forskolin (FSK) was used, which increased KGN cell size and mitochondrial DNA within 24 h. MitoTracker experiments and ultrastructural 3D reconstruction revealed that FSK treatment induced the formation of elaborate mitochondrial networks. H89, a protein kinase A (PKA) inhibitor, reduced network formation. A proteomic analysis indicated that FSK among others elevated levels of regulators of the cytoskeleton and the steroidogenic enzyme CYP11A1, located in mitochondria, was more than 3-fold increased, implying that cAMP/PKA-associated structural changes go in parallel with the acquisition of steroidogenic competence of mitochondria in KGN cells. In summary, in situ observations showed increases in mitochondria and suggested intracellular trafficking in GCs during follicular growth and indicated that they may partially be under the control of gonadotropins/cAMP. In line with this, elevation of cAMP in KGN profoundly affected mitochondria dynamics in a PKA-dependent manner and implicated cytoskeletal changes.