Steroid hormones are ancient signaling molecules that play fundamental roles in development and disease. For instance, steroid hormones are critical regulators of reproductive tissues in humans, and are a key determinant of insect development. In addition, steroid hormones play crucial roles in maintaining mineral salt concentrations, and control stress as well as inflammatory responses in humans. Steroid hormones are usually released as pulses, thereby generating a systemic timing signal that functions to coordinate multiple physiological and developmental changes throughout the body. In Drosophila, pulses of the steroid hormone ecdysone govern all major developmental transitions, including the larval molts, the transformation of a larva to a pupa and metamorphosis. While we have a relatively good understanding of the enzymatic steps that synthesize the hormone, comparatively little is known about the complex signaling pathways that control these pulses. Currently, we are modeling the function of rare human disease genes in Drosophila by exploring their unexpected relationships to the cellular signaling pathways that control the regulation and production of steroid hormones pulses.