Novel role of Salt-Inducible Kinases (SIKs) in the Ovary: The production of mature eggs is the most crucial step towards female fertility. Egg maturation requires a close interaction between Follicle-Stimulating Hormone (FSH) and the Insulin-like Growth Factors (IGFs). Of these hormones, FSH is the primary drug used to stimulate egg production in patients with ovulatory dysfunctions. However, FSH is not always effective in these patients. To solve this significant clinical problem, we looked for factors that inhibit FSH actions in the ovary. We discovered that SIKs are expressed in human and rodent granulosa cells (see figure on the right) and that SIK inhibition enhances the stimulatory effect of FSH in the ovary. We hypothesize that SIKs are molecular gate-keepers that repress FSH actions and egg maturation. Since SIK activity can be modulated pharmacologically, our findings could provide benefits for novel therapies to treat ovulatory defects in humans. For instance, SIK-controlled mechanisms and pathways may be used to develop safer and more effective protocols to induce ovulation in infertile women or innovative methods of contraception. Understanding SIKs in ovarian function is a major focus of our current NIH funding. Novel crosstalk between gonadotropins and growth factors in the ovary: We recently described the interaction between FSH and locally produced IGFs on the regulation of granulosa cell (GC) differentiation. Until the publication of our findings, FSH actions were considered to be enough to stimulate the growth of ovarian follicles. Our in vivo and in vitro studies in mouse, rat, and human GCs demonstrated for the first time that the stimulatory effect of FSH in the ovary requires the presence of IGFs. Our discovery revealed that FSH actions are not enough to stimulate ovarian cell proliferation and follicle growth and demonstrate an essential role of the receptor of IGFs in the regulation of survival, proliferation, and differentiation of GCs in vivo. These novel findings represented a paradigm shift in our understanding of how FSH regulates ovarian function. The News and Views editorial called Female Fertility: It Takes Two to Tango (see full text here) reviewed and highlighted the importance of our findings and suggested implications beyond fertility, including ovarian cancer, puberty, and ovarian toxicology. Current funding and research efforts study the signaling crosstalk between FSH and Insulin-like Growth Factors in primary cultures of human ovarian granulosa cells.