摘要： Abstract: Objective To study the changes in endogenous neuregulin-1 (Nrg1) expression in the anterior pituitary of female
Wistar-Furth rats in different phases of the estrous cycle. Methods Female Wistar-Furth rats during estrous cycles were used.
RT-PCR was employed to study the changes in the expression of Nrg1 isoforms and their cognate receptors ErbB-2 and ErbB-4
in the anterior pituitary in different phases of the estrous cycle. Western blotting was used to detect Nrg1 expression at the
protein level. Immunofluorescence staining was used to identify hypophyseal cells expressing Nrg1 and observe the
localization and distribution of Nrg1 and functional phosphorylation of ErbB-4. The co-expression of Nrg1 and ErbB-4 in the
anterior pituitary of Rhesus monkey was also investigated. Results Some of the Nrg1 isoforms, especially type III Nrg1s, were
expressed at a higher level during the estrous cycle I (E1) and estrous cycle II (E2), a result consistent with that of Western
blotting for samples of the anterior pituitaries collected at these phases. Immunofluorescence staining identified the
gonadotrophs as the main source of Nrg1, and showed an extensive distribution of Nrg1 in the anterior pituitary in E1 and E2
phases accompanied by apparent phosphorylated activation of ErbB-4. Adjacent distribution of Nrg1- and ErbB-4-positive
cells was also observed in the anterior pituitary of male Rhesus monkeys. Conclusion Our results provide evidence for the
expression of multiple Nrg1 isoforms and the presence of Nrg1/ErbB-4 signaling in the anterior pituitary of female
Wistar-Furth rats. This signaling demonstrates an estrous cycle phase-related pattern. Additionally, Nrg1/ErbB-4-based
juxtacrine signaling may exist in the anterior pituitary of male non-human primate.