STRESS PROMOTES DEVELOPMENT OF OVARIAN CYSTS IN RATS - THE POSSIBLE ROLE OF SYMPATHETIC-NERVE ACTIVATION

Activation of the sympathetic innervation precedes the induction of po lycystic ovaries in rats given estradiol valerate (EV). The mechanism of induction by EV may thus involve both direct and neurogenic compone nts. We tested this hypothesis using a combined cold and restraint str ess to induce an increase in sympathetic tone, including that of the o varian sympathetic nerves. Three weeks after the start of stress we fo und: 1. An increase in the content of norepinephrine (NE) in the celia c ganglion. 2. An increase in the release of NE from the ovary. 3. An unchanged NE uptake by the ovary. 4. An unchanged content of NE in the ovary. The ovarian content of neuropeptide Y (NPY) (colocalized with NE) was significantly decreased. These results suggest that NE synthes is and its secretion are increased during this period and correlate wi th the increase in secretion of androgens and estradiol, the developme nt of precystic follicles, and a decrease in the ovulatory rate. After 11 wk, NE release had returned to control values, whereas the ovarian NE content had risen significantly, suggesting a maintained high rate of NE synthesis. In the ovary, NPY contents, steroid secretion, morph ology, and ovulation had returned to the control state. These results suggest the participation of an extraovarian factor that might act loc ally to control the release of NE from the ovary, and further support the hypothesis that increased sympathetic activity plays a role in the development and maintenance of ovarian cysts.