Ontogenic development of corticotrophs in fetal buffalo (Bubalus bubalis) pituitary gland

Abstract

To evaluate the subpopulation of corticotrophs in developing buffalo (Bubalus bubalis) fetus, recovered pituitary glands (n=6 per group) from late first, second and third gestational female buffalo dams. The corticotrophs were identified by using specific antibodies against proopiomelanocortin (POMC) and adrenocorticotrophic hormone (ACTH) through immunohistochemistry. There was a significant (P≤0.05) increase of immunoreactive (ir) ir-ACTH cells during late 2nd trimester while, ir-POMC cells were more (P≤0.05) at late 3rd trimester of gestation as compared to other age groups. The quantity of co-localized cells for POMC and ACTH was significantly (P≤0.05) greater at the end of 1st gestation rather than 2nd and 3rd gestational fetal adenohypophyseal cells. This study is the first to demonstrate co-localization of POMC+ACTH and the affect of gestational age on the expression of these cells in buffalo fetus adenohypophysis.

Figure 1.

Immunofluorescent staining for ACTH (Cy3) and POMC (Cy2) at 600x. Images from first (A), second (B) and third (C) trimester of gestation male buffalo fetus pituitary gland demonstrating double immunofluorescent staining for ACTH and POMC. Dotted arrow shows co-localization of ACTH and POMC. Normal arrow shows POMC in cells and round head arrow shows ACTH in cells. Scale bars: 20 µm.

Figure 2

Immunohistochemical images of buffalo fetus anterior pituitary gland during first, second and third trimester of gestation. (A; ACTH, B; POMC, C; co-localization of ACTH and POMC) at the age of 3 month fetus, (D; ACTH, E; POMC, F; co-localization of ACTH and POMC) at the age of 6 months, (G; ACTH, H; POMC, I; co-localization of ACTH and POMC) at 9 months of fetus age. Blue arrow shows individual cells having ACTH. White arrow shows individual cells having POMC granules, while yellow arrow shows the evidence of ACTH and POMC co-localization (yellow cells) in specific cell. Magnification: 400x.

Figure 3

Mean ± SEM proportion of corticotroph cells subpopulation at 3 months (plane white), 6 months (plane gray) and 9 months of gestation (white, hatched) fetuses. A-C, superscript letters indicate significant differences between animal age groups or between cell types (P≤0.05).