Stress Increases Gonadotropin Inhibitory Hormone Cell Activity and Input to GnRH Cells in Ewes.

Stress reduces GnRH and gonadotropin secretion in sheep, but the central mechanism for this suppressive effect is unknown. Gonadotropin-inhibitory hormone (GnIH) negatively regulates GnRH neurons and gonadotropes. Here, we measured activity of GnIH neurons and contact of GnIH fibers on GnRH neurons during either chronic "pseudostress" or acute stress in sheep.