Investigation of the effects of asprosine on the hypothalamic-pituitary-adrenal axis

Peripheral tissues can transmit hunger-related hormones secreted due to changes in body energy metabolism to the central nervous system (CNS) to stimulate appetite. These hormonal changes, sensed by the hypothalamus in the CNS, elicit behavioral and neuroendocrine responses. Asprosin, an orexigenic and glucogenic hormone released from white adipose tissue, is known to cross the blood-brain barrier and interact with neurons in the paraventricular nucleus (PVN) of the hypothalamus. The aim of this study is to obtain data on the effects of asprosin hormone on the hypothalamo-pituitary-adrenal (HPA) axis, given its ability to cross the blood-brain barrier and influence PVN neuron activity. Our research was conducted on male and female Sprague Dawley rats. Each group included seven animals. Experiments were conducted using two different protocols. Protocol 1 included groups receiving central (intracerebroventricular (ICV)) asprosin injections at low, medium, and high doses (25, 50, and 75 nM). Protocol 2 included groups receiving two different doses of peripheral asprosin (intramuscular at 10 µg/kg and 20 µg/kg). Hypothalamic corticotropin-releasing hormone (CRH), serum adrenocorticotropic hormone (ACTH), and corticosterone (CORT) levels in protocols 1 and 2 were assessed using ELISA. Statistical analyses were performed using one-way ANOVA and Fisher's least significant difference (LSD) test. The independent samples t-test was used for the statistical comparison of central and peripheral analysis results between male and female animals, and p<0.05 was considered statistically significant. Hypothalamic CRH, serum ACTH, and CORT levels were found to be lower in the asprosin central groups compared to the control group (p<0.05). The result was not dose-dependent and was not statistically significant (p>0.05). Similarly, no significant effect was observed in protocol 2 (p>0.05). Our results indicated that the central effect of asprosin suppressed HPA axis activity, while the peripheral effect was not significant. Furthermore, this effect on the HPA axis was observed to be similar in both male and female animals. These results indicate that asprosine has a central suppressive effect on the physiology and pathophysiology of stress.