Investigation of immunohistochemical distribution of phoenixin and nesfatin-1 in biological tissues of adult female and male rats

Neuropeptides are various neuronal signaling molecules that regulate cellular and physiological functions in neuroendocrine systems. Among the recently discovered neuropeptides, important pleiotropic roles are pointed out for phoenixin (PNX) and NUCB2/nesfatin-1, which have been reported to co-localize and potentially interact in several hypothalamic nuclei. In this study, it was aimed to investigate the immunohistochemical distribution of PNX and nesfatin-1 in the biological tissues of adult female and male rats. For this purpose, 6 female and 6 male rats -a total of 12 Spraque-Dawley rats- that were 3-4 months old, were decapitated and their brain, cerebellum, liver, lung, kidney, adrenal gland, ovary, uterus and testis tissues were quickly removed. Tissues were fixed by immersion method in 10% neutral buffered formalin solution for immunohistochemical examinations. PNX-14 and NUCB2/nesfatin-1 immunoreactivities in the tissues were examined by applying the immunohistochemistry staining procedure according to the avidin-biotin-peroxidase complex method. Intense PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in the brain tissue of female rats, while moderate PNX-14 and intense NUCB2/nesfatin-1 immunoreactivity were observed in the cerebellum tissue. Mild PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in liver tissue, while moderate PNX-14 and intense NUCB2/nesfatin-1 immunoreactivity were observed in lung tissue. Moderate PNX-14 and intense NUCB2/nesfatin-1 immunoreactivity were observed in the kidney tissue, while intense PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in the adrenal gland. Intense PNX-14 and moderate-intense NUCB2/nesfatin-1 immunoreactivities were observed in ovarian and uterine tissues. Intense PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in the brain tissue of male rats, while mild PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in the cerebellum tissue. Moderate PNX-14 and NUCB2/nesfatin-1 immunoreactivity were observed in liver tissue, while intense PNX-14 and NUCB2/nesfatin-1 immunoreactivity were observed in lung tissue. Intense PNX-14 and moderate-intensity NUCB2/nesfatin-1 immunoreactivity were observed in the kidney tissue, while intense PNX-14 and moderate NUCB2/nesfatin-1 immunoreactivity were observed in the adrenal gland. Moderate PNX-14 and intense NUCB2/nesfatin-1 immunoreactivity were observed in testis tissue. In conclusion, considering the distribution of these two neuropeptides in the central and peripheral tissues of both female and male rats, it is thought that they play very important roles in the regulation of many neuroendocrine and physiological activities. Keywords :Phoenixin, nesfatin-1, rat, immunohistochemistry