What does low serum corticosterone, but high plasma ACTH indicate in stressed rats?
Answers
Answer:
Explanation:
After almost a month of Chronic Unpredictable Mild Stress (CUMS), both of my control rats (no stress) and stress-model rats exhibit low serum corticosterone concentration. Surprisingly, the level of ACTH in stress-model rats were significantly higher compared to control rats. Is it a common observation? Because most CUMS literature i found report high corticosterone level in their stressed rats.
ACTH is made in the corticotroph cells of the anterior pituitary gland, where it is released in bursts into the bloodstream and transported around the body. Like cortisol, levels of adrenocorticotropic hormone are generally high in the morning when we wake up and fall throughout the day (reaching their lowest level during sleep). This is called a diurnal (circadian) rhythm. Once adrenocorticotropic hormone reaches the adrenal glands, it binds on to receptors causing the adrenal glands to secrete more cortisol, resulting in higher levels of cortisol in the blood. It also increases production of the chemical compounds that rat an increase in other hormones such as adrenaline and noradrenaline.