Pro-opiomelanocortin mRNA and peptide co-expression in the developing rat pituitary

Abstract

Pro-opiomelanocortin (POMC) is synthesized in both the pituitary gland and the brain. Various peptide products of this precursor, namely beta-endorphin, ACTH and alpha-MSH are co-localized in the anterior lobe corticotrophs, all intermediate lobe cells and in hypothalamic neurons. Messenger RNA (mRNA) for POMC has further been shown to exist in these tissues. In this study, we have shown that POMC mRNA, and peptide accumulation as detected by in situ hybridization and immunocytochemistry, respectively, occur simultaneously within the rat pituitary gland during ontogeny and that their maturation occurs in parallel during prenatal and early postnatal development.

Cell Type-Specific Sexual Dimorphism in Rat Pituitary Gene Expression During Maturation1

“…Sexual differentiation of rat pituitary functions has been extensively studied at the level of hormone production and release, leading to a better understanding of developmental phases and puberty. There have also been several attempts to characterize the sexspecific transcriptional activity in pituitary glands in developing animals using various methods [7][8][9][10][11][12]. However, none of these studies analyzed the differentiation of gene expression for all five secretory cell types in both sexes during development.…”

Aversive stimulation during the stress-hyporesponsive period does not affect the number of corticotroph cells in neonatal male rats

“…Several studies have been conducted to identify the site(s) of this insensitivity or immaturity (9,10). Immunocytochemical studies have demonstrated that ACTH cells can be distinguished as early as at 14-16 days of fetal age in rats (11). The pituitary is functionally responsive to certain stressors until 1-2 days after birth, but then ACTH levels decrease to a minimal level until postnatal days 10-11 (7,9,10).…”