| Hypothalamic sections taken from 11 adolescent Yorkshire pig brains, 5 male, 6 female were subjected to proliferating cell nuclear antigen (PCNA) immunohistochemistry. Antigens were retrieved by a microwave heating treatment. Sections were counter-stained with Mayer's Haematoxylin to locate the vasopressin/oxytocin-containing nucleus (VON). To discriminate between PCNA positive glial and neuronal cells, double-labelling with glial fibrillary acidic protein (GFAP) was performed. All animals exhibited PCNA positive nuclei in the vicinity of, and within the VON. Often, visibly identifiable neurons contained PCNA positive nuclei. Nuclei greater than 7 {dollar}mu{dollar}m in diameter were considered of neuronal lineage. Supporting this, all GFAP positive cells had a nuclear diameter of 5 {dollar}mu{dollar}m or less. Counts of PCNA positive neurons demarcated a putative hypothalamic subependymal proliferative zone. While the hypothesis of neurogenesis in VON growth is supported, further research using other markers for proliferation and cell lineage is indicated. |
