Ultrastructural Changes in the Adenohypophysis, Adrenal Gland Activity, and Desynchronization of the Oestrous Cycle following Unpredictable Stress in the Rat

Abstract

An ultrastructural study of the adenohypophysis, after exposure of female Wistar rats to a signalled unpredictable 5-and I5-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 I5-day stress period respectively.

Effects of stress administered during pregnancy on reproductive capacity and subsequent development of the offspring of rats: prolonged effects on the litters of a second pregnancy

“…Of particular importance are the levels of placental trophic hormones, pituitary and adrenal cortical hormones, both maternal and fetal thyroid hormones, sex hormones and maternal insulin. Stress of the present type alters the levels of a variety of hormones associated with the hypothalamic pituitaryadrenal (Pollard & Cairncross, 1977) -thyroid (Pollard, Bassett & Cairncross, 1979) and -gonadal (Pollard, Bassett & Joss, 1980) axes in the rat. High maternal levels of corticosteroids crossing the placenta may alter fetal secretion of pituitary hormones.…”

Pre- and Postpubertal LH and Estradiol Pattern in Gilts Subjected to Intermittent Inescapable Electroshock

“…Such evidences, combined with the results of the present study, may therefore question the use of treatment with synthetic glucocorticoids or ACTH as a model for studying stress-related suppression of the HPG-axis in the pig. In other species, however, more dramatic effects of chronic treatment with electroshock have been found on activity in both the HPAand the hypothalamus-pituitary-gonadal-axis (RPG-axis) (Przekop et al 1984, Rivier et al 1986, Pollard & Cairncross 1977. Such divergent results among different species may reflect species differences in the sensitivity of the HPG-axis to stress as well as differences caused by the experimental procedure such as the intensity and duration of the electroshock sessions.…”

“…The purpose of the present experiment was therefore to elucidate the effect of exposure to a standardized psychological stressor during the growing period on the LH and estradiol secre-tory pattern around the time of initial boar exposure and first boar induced ovulation in gilts. Electroshock was chosen as this treatment has caused depression of LH and estradiol in several species (Przekop et al 1984, Rivier et al 1986, Pollard & Cairncross 1977. In addition, electroshock treatment is standardizable and minimizes interference between the stressor and normal biological functions while maintaining similar stimulus situations in the control and stress group.…”