Pituitary-Testicular Responses in Rams to Prolonged Infusions of Luteinizing Hormone-Releasing Hormone (LHRH)1

Abstract

The appearance of gap junctions between decidual cells and the restructuring of the intercellular matrix of the endometrium was studied by electron microscopy in the developing primary deciduoma of the pseudopregnant rat uterus. Decidualization was induced by intraluminal injection of Hanks balanced salt solution at the time of peak sensitivity (Day 4). The progression of decidualization was followed through Day 9 of pseudopregnancy. At the time of sensitivity the periluminal stromal cells of the antimesometrial region are surrounded by an abundant collagenous matrix and there are relatively few contacts between processes of neighboring cells. When junctions exist they are of the maculae adherentes type. On the day following the deciduogenic stimulus (Day 5) contacts between cells are numerous and gap junctions are present. The presence of gap junctions between the early differentiating decidual cells suggests that cell to cell communication may be involved in the spread of decidualization. As decidualization progresses a rapid reduction in the amount of intercellular matrix occurs. With continued growth extensive infoldings and interdigitations of the plasma membranes develop between adjoining decidual cells forming a complex membranous labyrinth. Numerous gap junctions are present involving extensive areas of the cell surfaces. By Day 9 the antimesometrial region consists of large, polyploid, glycogen-rich decidual cells with extensive surface infoldings that are joined by gap junctions.