Systemic regulation of GSCs. (A) Diagram illustrating that female GSCs are regulated by interorgan communication involving the brain and adipocytes through signals that act on the niche, GSCs, or through intermediate organs. (B) Diagram of male GSC next to hub illustrating the known roles of insulin-like peptides and ecdysone in controlling GSC maintenance and proliferation. See text for additional details. EcR, ecdysone receptor; GSC, germline stem cell; InR, insulin receptor; PI3K, phosphoinositide 3 kinase; TOR, target of rapamycin; PE, phosphatidylethanolamine.