ROLE OF OREXINS IN THE HYPOTHALAMIC-PITUITARY-OVARIAN RELATIONSHIPS

P. SILVEYRA ; NI. CATALDI , VA. LUX-LANTOS AND C. LIBERTUN

ACTA PHYSIOLOGICA SCANDINAVICA

Wiley-Blackwell

Año: 2010 vol. 198 p. 355 - 360

0001-6772

Appropriate nutritional and vigilance states are needed for reproduction. We hypothesized that orexins may play a role in this integration. In previous works, by measuring the expression of preprorexin (PPO), Orexin receptor 1 (OX1) and Orexin receptor 2 (OX2) in brain, pituitary and ovary of female cycling rats during the oestrous cycle; and by treatment with ovulation (Cetrorelix or Pentobarbital), OX1 (SB-334867-A) or OX2 (JNJ-10397049) blocking agents; we described the influence of the hormonal milieu of proestrus on the orexinergic system. Furthermore, we found that OX1 expression in hypothalamus, but not other neural areas, and adenohypophysis is under the influence estradiol and the time of the day (afternoon of proestrus). We have demonstrated that information from the sexual hormonal milieu of proestrous afternoon impacts on various components of the orexinergic system; alertness on this particular night of proestrus would be of importance for successful reproduction. In this review, we summarize the available experimental data supporting a role of orexins in the hypothalamic-pituitary-ovarian relationships. All together, these results suggest a role of the orexinergic system as an integrative link among vital functions, reproduction, food intake, alertness and the inner biological clock.