Influence of stress on reproduction: involvement of the melanocortin receptor type 2 in ovarian response to adrenocorticotropic hormone

ETCHEVERS L; BELOTTI EM; HUBER E; SALVETTI NR; REY F; ORTEGA HH; AMWEG AN

Mar del Plata

Congreso; LXII Reunión anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2018

Cattleundergo numerous environmental, management and nutritional stressors throughoutthe reproductive cycle. In response to stress, adrenocorticotropic hormone(ACTH) acts on adrenal gland promoting glucocorticoids synthesis and secretion,which are implied in metabolism, inflammatory response and reproduction. Theaim of the present study was to evaluate the protein expression of MelanocortinReceptor 2 (ACTH receptor, MC2R) and its accessory protein (MRAP2) in thepreovulatory follicles in the ovary of cows treated with ACTH. Holstein cows(n=16) were divided into two groups: Control group (administrated with salinesolution) and ACTH group (administrated with 100 UI of ACTH) every 12 hoursduring 4 days before expected time of ovulation until ovariectomy. MC2Rexpression was higher in theca interna cells from preovulatory follicles of ACTHgroup relative to Control group (p< 0.05), whereas in granulosa cells it wassimilar in both groups (p> 0.05). MRAP2 expression was similar in both celltypes from both groups analysed (p> 0.05). In addition, higher concentrationof cortisol was detected in follicular fluid and serum of ACTH group relativeto Control group (p< 0.05). Also, higher concentration of progesterone wasdetected in serum of ACTH group (p< 0.05). These results show that thebovine ovary is able to respond locally to the ACTH released as a consequence ofstress. Moreover, these results indicate that ACTH, through its specificreceptor, may be involved in regulatory mechanisms related to ovarian functionssuch as ovulation, steroidogenesis and in the pathophysiology of variousreproductive diseases in cattle.