Category: Endocrine

The thyroid gland’s main job is producing the two thyroid hormones: thyroxine (T₄) and triiodothyronine (T₃). These hormones influence cellular metabolism, including increasing cellular oxygen consumption and increasing protein synthesis.

Cortisol is probably the most well known of the glucocorticoids, which are produced by the zona fasciculata of the adrenal cortex. Its main functions are increasing blood sugar by increasing glucose synthesis, suppression of the immune system, and metabolism of other energy sources like fats, proteins and carbohydrates. Because it has such varying effects, having a dysfunction in cortisol levels can be very significant for the animal!

𝐂𝐡𝐞𝐦𝐨𝐝𝐞𝐜𝐭𝐨𝐦𝐚𝐬 are tumours derived from the 𝐧𝐞𝐮𝐫𝐚𝐥 𝐜𝐫𝐞𝐬𝐭, which is a group of cells that develop into neurons and other nervous tissue. These tumours most commonly develop from the 𝐜𝐚𝐫𝐨𝐭𝐢𝐝 𝐚𝐧𝐝 𝐚𝐨𝐫𝐭𝐢𝐜 𝐛𝐨𝐝𝐢𝐞𝐬 near the heart.

CHD is a syndrome of foals primarily characterized by enlarged thyroid glands and deformities of the limbs. This syndrome was first described in Western Canada by one of my current professors. Small world!

𝐄𝐌𝐒 is an endocrine dysfunction of 𝐢𝐧𝐬𝐮𝐥𝐢𝐧, the body’s main hormone it uses to get 𝐠𝐥𝐮𝐜𝐨𝐬𝐞 (the main sugar used for energy) into cells. In normal horses, insulin levels increase when blood glucose levels increase, to help store the glucose away in cells and provide the cells energy. In EMS horses, they typically have 𝐡𝐲𝐩𝐞𝐫𝐢𝐧𝐬𝐮𝐥𝐢𝐧𝐞𝐦𝐢𝐚, which is when there are high levels of insulin despite normal levels of blood glucose.

𝐏𝐏𝐈𝐃 is an endocrine dysfunction caused by an 𝐚𝐝𝐞𝐧𝐨𝐦𝐚 (a benign tumour) in the pituitary gland of the horse. The pituitary gland’s main job is to produce hormones that control the other hormone-secreting organs, such as the adrenal glands or thyroid gland. So when it develops an adenoma, the tumour can interfere with the normal hormone production of the pituitary gland, causing issues like PPID.