Ultrastructural changes in the adenohypophysis, adrenal gland activity, and desynchronization of the oestrous cycle following unpredictable stress in the rat.

An ultrastructural study of the adenohypophysis, after exposure of female Wistar rats to a signalled unpredictable 5- and 15-day stress regimen, is described. Cellular activity of the adenohypophysis correlated well with the circulating levels of corticosterone. Intense secretory activity was observed in all tropic cell types at 5 and 15 days although the observed differences generally were greater in the 5-day stressed group. It was observed that the oestrous cycles of 40 and 100% of the rats became desynchronized over the 5- and 15-day stress period respectively.