DIETS THAT HAVE POTENTIAL TO STIMULATE THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS IN SPRAGUE DAWLEY RATS

Abstract

The pituitary gland is the master gland which regulates the body hormones. From the corticotrophs of the anterior pituitary gland, adrenocorticotrophic hormone (ACTH) is secreted and influences corticosterone production in rodents via the hypothalamic–pituitary–adrenal axis (HPA axis). ACTH and corticosterone are frequently used as a hormonal marker of stress level. Disturbance in ACTH and corticosterone were observed in many diseases especially Addison’s disease, Cushing’s syndrome, and metabolic syndrome. Our objective is to observe which diet produces the most and least stress to the Sprague Dawley rat’s physiology. Method: Thirty-five Sprague Dawley rats were grouped into five groups (n=7) and were given five different types of diets (control, high-fat, high-protein, high-sugar, and high-starch) with tap water supplied as drinking water ad libitum. By the end of eight weeks, the rat’s blood was collected, and serum separated. The individual components of ACTH and corticosterone from the blood was extracted, purified, identified, and quantified using the High-Performance Liquid Chromatography (HPLC) with photodiode array (PDA) analysis method. Result: The analytical studies revealed a high -sugar diet registered highest ACTH blood level. It was also revealed that the high-fat and high-sugar diet group presented with the highest peak for corticosterone. Conclusion: Consumption of high-fat and high-sugar diet for eight weeks is suggested to induce physiologic and metabolic stress in Sprague Dawley rats as evidenced by the HPA activation.