Question

The neuropeptide synthesized and released from the CNS, particularly the hypothalamus, as well as from immune cells is a. \(\mathrm{ACTH}\) b. urocortin-1 c. \(\mathrm{CRH}\) d. TNF- \(\alpha\) e. insulin

Short answer

Answer: c. \(\mathrm{CRH}\)

Step-by-step solution

Understand the options.

To solve this problem, it is necessary to know the main function and origin of each option. Here is a brief overview of each option: a. \(\mathrm{ACTH}\): Adrenocorticotropic hormone, or \(\mathrm{ACTH}\), is a hormone that stimulates the adrenal glands to produce cortisol in response to stress. b. Urocortin-1: Urocortin-1 is a neuropeptide that has been shown to play a role in the mediation of stress and anxiety responses. It is related to the corticotropin-releasing factor (CRF). c. \(\mathrm{CRH}\): Corticotropin-releasing hormone, or \(\mathrm{CRH}\), is a peptide hormone involved in the stress response. It is the primary release factor for \(\mathrm{ACTH}\) and is synthesized in the hypothalamus. d. TNF-\(\alpha\): Tumor necrosis factor alpha, or TNF-\(\alpha\), is an immune cell-derived cytokine that is involved in systemic inflammation. It is primarily released by activated macrophages. e. Insulin: Insulin is a peptide hormone involved in the regulation of glucose metabolism. It is produced in the pancreas.

Identify the correct option.

According to the descriptions given in Step 1, \(\mathrm{CRH}\) (corticotropin-releasing hormone) is the correct option. It is synthesized and released from the CNS (particularly the hypothalamus) and plays a crucial role in the stress response by stimulating the release of \(\mathrm{ACTH}\). Answer: **c. \(\mathrm{CRH}\)**

Key concepts

Corticotropin-releasing hormone (CRH)

Corticotropin-releasing hormone, commonly abbreviated as CRH, is a central player in the body's adaptive response to stress. This hormone is a small peptide synthesized in the hypothalamus, a critical brain region for controlling endocrine and autonomic functions.
One of its primary roles is to trigger the release of adrenocorticotropic hormone (ACTH) from the pituitary gland. Once released, ACTH travels through the bloodstream to the adrenal glands, prompting them to secrete cortisol, a hormone essential for managing stress. This hormonal sequence is an important part of what is known as the hypothalamic-pituitary-adrenal (HPA) axis.
The significance of CRH extends beyond just this pathway; it affects the immune system and has been linked to mood disorders. Understanding CRH can provide insights into various stress disorders and potential therapeutic targets.

Hypothalamus

The hypothalamus is a small yet crucial part of the brain that plays a vital role in maintaining the body's homeostasis, which means keeping the body's internal environment stable and balanced. It's often called the 'control center' of the endocrine system due to its broad influence over bodily functions.
Located below the thalamus, this small region is responsible for producing various neuropeptides, including CRH, which is crucial in handling stress. The hypothalamus coordinates with the pituitary gland to form a significant component of the HPA axis, regulating stress responses, emotions, and even body temperature.
Functions of the hypothalamus include:

• Regulating hunger, thirst, and sleep.
• Controlling body temperature.
• Managing emotional responses.

The hypothalamus is essential for keeping us functioning optimally by ensuring that several critical processes are working smoothly.

Stress response

The stress response is the body's survival mechanism, enabling us to react quickly to threatening situations. When a person perceives stress, the brain triggers various physiological changes to enable the body to respond effectively.
At the core of this response is the release of CRH from the hypothalamus.

• CRH initiates the HPA axis response, resulting in cortisol release, which mobilizes energy and resources for the body to cope with stressors.
• This physiological preparation involves increasing heart rate and energy levels, sharpening focus and alertness.
• It's a finely tuned system ensuring that the body can handle challenges efficiently.

However, chronic exposure to stress can lead to overactivation of this system, resulting in various health problems including anxiety, depression, and cardiovascular issues. Hence, understanding and managing the stress response is crucial in maintaining overall health and well-being.