NEONATAL PORCINE ENDOMETRIAL DEVELOPMENT INVOLVES COORDINATED CHANGESIN DNA-SYNTHESIS, GLYCOSAMINOGLYCAN DISTRIBUTION, AND H-3 GLUCOSAMINELABELING

To determine whether neonatal porcine endometrial development involved alterations in endometrial DNA synthesis, glycosaminoglycan (GAG) dis tribution, and/or H-3-glucosamine labeling, gilts were assigned random ly at birth (Day 0) to be hysterectomized on either Day 0, 7, 14, 28, 42, or 56. Uteri were processed for histology and Alcian blue-8GX (AB) histochemistry or cultured as explants in the presence of [methyl-H-3 ]thymidine (H-3-Thd) or D-[6-H-3]glucosamine (H-3-GlcN) and processed for subsequent autoradiography. For H-3-Thd-labeled tissues, labeling index (LI; % of nuclei labeled) was determined for two endometrial tis sues (epithelium and stroma); two epithelial areas (luminal and glandu lar); and, for glandular epithelium, in three endometrial zones (zone 1 = shallow, zone 2 = intermediate, zone 3 = deep). For H-3-GlcN-label ed tissues, LI (grains/100 mum2) was determined for two stromal zones (shallow and deep). Endometrial glands were absent on Day 0, present i n shallow stroma on Days 7 and 14, and extended to the myometrium in t issues from Day 28 through Day 56. Appearance of endometrial glands wa s associated with a dramatic increase in glandular epithelial H-3-Thd LI, which was maximal on Days 7 and 14 and declined thereafter. When g lands were present in all three endometrial zones (Days 28-56), glandu lar epithelial H-3-Thd LI was consistently greatest in zone 2. Stromal H-3-Thd LI decreased after Day 0. In tissues obtained after Day 0, a distinct zone of alcianophilia was observed in shallow stroma adjacent to luminal epithelium and surrounding the necks of newly developed en dometrial glands. This staining pattern was marked in tissues from Day s 7, 14, and 28. Generally, stromal H-3-GlcN LI was greater in shallow than in deep stromal zones; it decreased after Day 0 to minimum value s on Days 28 and 42 in both zones, and increased slightly in shallow s troma on Day 56. Data indicate that development of the neonatal porcin e endometrium between birth and Day 56 involves coordinated alteration s in patterns of DNA synthesis, GAG distribution, and glycoconjugate b iosynthesis. The morphogenetic processes characterized here are likely to be regulated locally via changes in tissue microenvironment.