Variations in the adenohypophysis of the expression of proliferating cellular nuclear antigen, oestrogen and androgen receptors in relation to gonadal steroids during pregnancy of viscachas (Lagostomus maximus maximus)

Abstract

Viscachas are native rodents of South America that present a long pregnancy of ~154 days. In this work, we analysed variations in the expression of proliferating cellular nuclear antigen, oestrogen and androgen receptors (ERα and AR) in pituitary pars distalis (PD) and pars tuberalis (PT) in relation to oestradiol and testosterone serum levels in non-pregnant and pregnant viscachas. In PD, cell proliferation increased with pregnancy and lactotrophs proliferated during mid-pregnancy (MP). ERα nuclear-immunoreactive cells (ERαn-ir) were maximal in late pregnancy and AR expression did not vary during pregnancy. In PT, cell proliferation and AR expression increased during pregnancy, but ERα expression was very scarce. The immunostaining pattern of receptors was different in PD and PT. The peak of serum oestradiol and testosterone occurred during MP. Our results suggest that cell proliferation and gonadal receptors might be differentially regulated in the pituitary by oestradiol and testosterone during viscacha pregnancy.

Influence of melatonin and sexual hormones on the expression of proliferating cell nuclear antigen in the adrenal cortex of a seasonal breeder (Lagostomus maximus)

“…Pregnant viscachas were classified into three different groups according to the number and size of embryos or fetuses: early-pregnancy (captured during autumn, April-June, with two or more embryos from 1 to 3 cm; n = 4), mid-pregnancy (captured during winter, July-August, with two fetuses from 9 to 11 cm; n = 4) and late-pregnancy (captured in spring, September-December, two fetuses measuring more than 19 cm; n = 4). This classification was performed according to previous reports by Gil et al (2007), Filippa and Mohamed (2010), Mohamed (2017), andRosales, Perez, Rodriguez, Filippa, andMohamed (2019).…”

“…The anti-PCNA monoclonal primary antibody used in the present study (PCNA, Catalog No. AM 252-5M; BioGenex, San Ramon, CA) has already been used with successful results in viscacha (Rosales et al, 2016(Rosales et al, , 2019. After rinsing the sections in PBS for 10 min, the immunohistochemical visualization was achieved using the Super Sensitive Ready-to-Use Immunostaining Kit (BioGenex, San Ramon, CA) as follows: sections were incubated for 30 min with biotinylated anti-IgG, washed in PBS and then incubated for 30 min with horseradish peroxidase-conjugated streptavidin.…”