Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

One reason why fish and mammals lose their appetite during stress

Photo by Inzmam Khan on Pexels.com

I don’t know about you, but sometimes I lose my appetite when I am really stressed. The endocrine system is responsible for controlling our stress responses and involves three main endocrine glands – the hypothalamus, pituitary, and adrenal gland. Hence, the stress pathway is often referred to as the “HPA axis”. When we are stressed, the hypothalamus releases a hormone called corticotropin releasing factor (CRF), which triggers the release of adrenocorticotropic hormone (ACTH) from the pituitary gland in the brain. ACTH then travels through the bloodstream and stimulates the release of the stress hormone cortisol from the adrenal gland. In the case of fish, the last endocrine gland in the stress pathway are the interrenal cells, so this pathway is known as the “HPI axis”.

Diagram of the HPA axis from Wikimedia Commons

Nesfatin-1 is a peptide that is known to affect the stress pathway in mammals and cause a loss of appetite. Whether nesfatin-1 is involved in the stress response of goldfish (Carassius auratus) was the subject of a recent study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology.

Photo by Hatice Baran on Pexels.com

Interestingly, the researchers detected nesfatin-1 in each of the endocrine glands of the stress pathway in goldfish with the highest expression in the pituitary. The researchers also discovered that simply netting fish increases levels of nesfatin-1 in the forebrain, hypothalamus, and pituitary. In addition, administration of nesfatin-1 to fish increased levels of circulating cortisol and administration to isolated pituitary cells caused the cells to release ACTH. These findings suggest that nesfatin-1 not only helps suppress appetite when the fish are stressed, but it can also help regulate their stress response too.

V Pham, JG Pemberton, JP Chang, AM Blanco, A Nasri, S Unniappan. Nesfatin-1 stimulates the hypothalamus-pituitary-interrenal axis hormones in goldfish. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. 321(4): R603-R613, 2021.

Categories: Agriculture, Aquaculture, and Livestock, Intelligence and Neuroscience, Pets, Stress

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