In a mouse study, researchers tried to block a thymus hormone called thymosin‑alpha‑1 to see if it would fix an autoimmune ovarian problem caused by early removal of the thymus. The treatment didn’t stop the ovarian damage, but it did bring estrogen and testosterone levels back to normal, showing that the link between the thymus and ovaries is more complex than just one hormone.

Thymectomy at 3 days of age (Tx-3) in B6A female mice results in an autoimmune oophoritis that has only been successfully overcome by the transplant of an intact thymus or an injection of T cells. In Tx-3 mice levels of thymosin alpha 1 (TSN alpha 1), a potent thymic hormone involved in the development of helper T cells, was previously shown to be high after 7 days. By 60 days levels of TSN alpha 1 returned to levels found in intact mice. By this age ovarian dysgenesis was also complete and accompanied by high circulating levels of auto-oocyte antibody (AOA), estradiol-17 beta (E2) and testosterone (T). In the present study injections of antisera to TSN alpha 1 were given to Tx-3 mice in an attempt to decrease circulating TSN alpha 1 levels. We reasoned that this treatment should inhibit lymphocyte differentiation, and possibly in turn aid in overcoming the ovarian dysgenesis. After treatment of the Tx-3 mice, dysgenic ovaries persisted and high levels of AOA remained similar to the untreated Tx-3 mice. Levels of E2 and T, however, were returned to those found in intact mice. These results suggest that there is a sensitive balance between the thymus and the ovary that may not be related to changes in only a single thymic hormone.