Gender differences in expression and localization of the apelin receptor in mice skin.

The male and female mouse skin differs in their structure. Leptin, adiponectin, resistin and omentin are adipokines, which expresses in the skin. Apelin is an adipokines, which binds to a its receptor (APJ) and elicits various biological functions in the different tissues. However, the expression of apelin and APJ has not been shown in the mice skin. Since the male female differs, thus, it is hypothesized that apelin and APJ expression might also show gender-wise differences. Our results showed that apelin and APJ are expressed in the epidermal layer, hair follicle and sebaceous glands of male and female skin. This result suggests that apelin-mediated signalling could be different in the male and female skin. Hair follicle and sebaceous gland in the female skin also showed an increased abundance of apelin, which further suggests the role of apelin, in hair growth and sebaceous gland functions. Apelin-mediated signaling in the skin might be gender-dependent. Elevated expression of ERs in female skin coincides with increased apelin and APJ and decreased apelin and APJ expression in male skin coincides with the decreased androgen receptor. Thus, it may be suggested that sex hormonal signaling could be reason for gender wise difference in apelin and APJ expression in skin. Furthermore, apelin signaling would be important for both male and female skin physiological processes, however, apelin signaling could be pronounced in the female skin compared to the male skin. The exact role of gender base apelin signaling needs further investigation in relation proliferation.