Neonatal Ovine Uterine Development Involves Alterations in Expression of Receptors for Estrogen, Progesterone, and Prolactin1

Abstract

Effects of age on uterine histoarchitecture, cell proliferation, and hormone receptor expression were determined for neonatal ewe lambs from birth (Postnatal Day [PND] 0) to PND 56. Uteri were histologically evaluated and proliferating cell nuclear antigen (PCNA), estrogen receptor alpha (ER-alpha), progesterone receptor (PR), and prolactin receptor (PRL-R) expression were characterized by in situ hybridization (ISH), immunohistochemistry, or both. The most striking feature of neonatal uterine development was the genesis and development of glands in the intercaruncular areas of endometrium. After birth, endometrial glandular epithelium (GE) budded and differentiated into the underlying stroma from the luminal epithelium (LE) between PNDs 1 and 7. Between PNDs 14 and 56, extensive coiling and branching morphogenesis of nascent endometrial glands occurred. By PND 56, the uterine wall appeared to be histoarchitecturally mature. At birth, nuclear PCNA protein was strongly detected in LE. Between PNDs 7 and 56, high levels of PCNA, ER-alpha, and PR gene expression were detected in both nascent and developing GE. Higher levels of PCNA and ER-alpha expression were detected in GE at the tips of developing glands as well as in the surrounding stroma. Progesterone was below detectable limits in serum. Serum estradiol-17beta levels were high on PND 1, increased from PNDs 14 to 28, and declined from PND 42 to PND 56. Serum PRL levels increased from PNDs 1 to 14 and declined thereafter. Using ISH and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, expression of mRNAs for short and long forms of the ovine PRL-R were first detected in nascent GE on PND 7 and increased between PNDs 7 and 56 in proliferating and differentiating GE. These results indicate that 1) uterine gland genesis is initiated between PNDs 1 and 7 after birth and is essentially completed by PND 56; 2) neonatal uterine morphogenesis involves temporal and spatial alterations in cell proliferation and ER-alpha, PR, and PRL-R gene expression; 3) PRL-R expression is a unique marker of GE differentiation and proliferation; and 4) serum estradiol-17beta and PRL levels increase during the onset of GE tubular branching morphogenesis. Results support the hypothesis that neonatal ovine uterine development involves epithelial PRL-R and ER-alpha activation to stimulate and maintain endometrial gland genesis and branching morphogenesis.

Prolactin, the prolactin receptor and uncoupling protein abundance and function in adipose tissue during development in young sheep

“…Pituitary extract PRL (2 mg) administered once per day resulted in an increase in plasma PRL equivalent to that reported under long-day conditions (Bassett et al 1989, Taylor et al 2000, but the amount of PRL used in the present study was probably in excess of need. It is unlikely, therefore, that S179D PRL is 200-fold the potency of pituitary extract PRL.…”

Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs

“…Serum was then collected and stored at K20 8C for hormone analysis. Serum E 2 levels were determined by a double-antibody RIA procedure (DSL-4800; Beckman Coulter Ultra-Sensitive Estradiol RIA, Inc., Webster, TX, USA) (Taylor et al 2000, Carpenter et al 2003, validated for use with ovine samples. The RIA used rabbit anti-E 2 (polyclonal) serum and iodinated estradiol.…”

Nutritional manipulation between early to mid-gestation: effects on uncoupling protein-2, glucocorticoid sensitivity, IGF-I receptor and cell proliferation but not apoptosis in the ovine placenta

“…This was undertaken using a mouse MAB to PCNA (PC10) (Alexis Biochemicals, Bingham, Nottingham) at a 1:200 dilution. Relative staining intensity for immunoreactive nuclear PCNA expression was visually assessed in a blinded manner and scored as either absent (K; no nuclear staining), weak (C), moderate (CC), or strong (CCC) (Taylor et al 2000). Immunohistochemistry was performed on a computerized Bond automated immunohistochemistry system (Vision Biosystems Limited, Newcastle-upon-Tyne, UK) using a bond polymer refine detection kit.…”