Hormonal behavior correlates with follicular recruitment at mid-gestation in the South American plains vizcacha, Lagostomus maximus (Rodentia, Caviomorpha).

FRAUNHOFFER, NA; JENSEN F.; LEOPARDO N.; INSERRA PIF; MEILERMAN ABUELAFIA A; ESPINOSA MB; CHARIF SE; DORFMANA VB; VITULLO AD

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2017 p. 162 - 174

0016-6480

In mammals, hormonal regulationduring gestation is crucial for embryo implantation and pregnancy success. This regulation is controlled through the level of progesterone (P4) that blocks the activity of the hypothalamic-hypophyseal-gonadal (HHG) axis. Previous studies in the pregnant South American plains vizcacha, Lagostomus maximus, have shown that the HHG axis activates around mid-gestation promoting pre-ovulatory follicle formation. However, the characterization of the hormonal dynamics throughout gestation and its ovarian correlation has not been studied in depth. We studied the ovarian dynamics of L. maximus and its correlation with the hormonal profile during gestation, analyzing serum levels of P4, 17B-estradiol (E2), 4D-androstenedione (A4), luteinizing hormone (LH) and follicle stimulating hormone (FSH) as well as the ovarian distribution and expression of their receptors. additionally, we have analyzed the folliculogenesis and accesory corpora lutea (ACL) formation. P4 showed two concentration peaks reaching its highest level at mid -gestation decreasing at 91 - 100 days post-coitum. P4 decrease is followed by an increase of circulating levels of A4, E2, FSH and LH and with an elevated number of antral/pre-ovulatory follicles which express PGR, ESR1, ESR2, AR, LHR and FSHR. In addition, ACL with oocyte retention and cytoplasmic lipid droplets in luteal cells were detected at this time point. These results show that in L. maximus the decrease of P4 level from mid-gestation enables follicular recruitment until pre-ovulatory stage and the development of functional ACL.