title: Effects of advancing age on the ultrastructure of pinealocytes in the male white-footed mouse (Peromyscus leucopus).
abstract: Quantitative comparison of pinealocyte ultrastructure in 3-month-old and 28-month-old male white-footed mice (Peromyscus leucopus) revealed decreases both in the area of the Golgi apparatus and in the number of dense-core vesicles. In contrast, no differences between these two age groups were noted in the areas of granular endoplasmic reticulum, vacuoles with flocculent content, lysosome-like bodies, or mitochondria. Nor were any changes between groups of mice apparent in pinealocyte nuclear or cytoplasmic areas, nuclear: cytoplasmic ratios, or the number of pinealocyte nuclei per unit area. Areas of unusual, annulate lamellae-like structures were increased in the pinealocytes of a group of 28-month-old mice. These observations suggest a possible age-associated decrease in the neurosecretory-like (but not ependymal-like) secretory process in the pinealocyte of white-footed mice.
mesh_terms: D000375:Aging; D000818:Animals; D003593:Cytoplasm / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D009490:Neurosecretory Systems / Q000502:physiology; D010542:Peromyscus / Q000033:anatomy & histology* / Q000502:physiology; D010870:Pineal Gland / Q000502:physiology / Q000648:ultrastructure*; D012098:Reproduction