The ultrastructure of pinealocytes in the pig

Abstract

Pinealocytes of female pigs were studied electron-microscopically and compared with those of other mammals. A prominent Golgi apparatus forming dense-cored vesicles was widely dispersed in the cytoplasm of the cell body. A very characteristic feature of the pig pinealocytes was the presence of membrane-bounded bodies showing wide variations in internal structure. Possible roles of the dense-cored vesicles and membrane-bounded bodies in secretory processes of pinealocytes are discussed.

Cell types in the pineal gland of the horse: An ultrastructural and immunocytochemical study

“…Yet, at least some of these granules may constitute waste products or debris resulting from the metabolic activity of pinealocytes. The presence of pigmented cells resembling melanophores in the connective se ta may be an excellent exformed by a n electron-lucent droplet surrounded by a denser component, i.e., neuromelanin-like granules, have also been found in the pineal gland of the pig (Gomez Dumm and Iturriza, 1979;Karasek and Wyrzykowski, 1980). Peroxisome-like bodies are probably related to lysosomal activity.…”

“…The mammalian ineal gland of many species, especially rodents, has lee, extensively analyzed with the aid of electron microscopy; however, relatively little information is available on the fine structure of the pineal gland of large domestic animals (Anderson, 1965;Karasek and Wyrzykowski, 1980). The horse is a domestic seasonal breeder and recent publications suggest that a circadian pattern exists in the secretion of the hormone melatonin by the ineal gland (Kilmer et al, 1982).…”

Morphofunctional aspects of the mammalian pineal gland

“…A possible role in pineal secretory processes has been also proposed for membrane-bound bodies in pinealocytes of the pig, wild boar, and miniature pig ( Fig. 19) (Karasek and Wyrzykowski, 1980;Wyrzykowski et al, 1986), and in the cotton rat for inclusion bodies (Figs. 21,221 (Karasek et al, 1982dKarasek, 1983)that is, structures which are highly specific for these species.…”

‘Synaptic’ Bodies in the Pineal Glands of the Cow, Sheep and Pig

“…Moreover, it was found that pigs do not show day/night differences in mela tonin synthesis 120] and that SB are rare in this species [21]. Although it is not known whether interrelationships exist between SB and melatonin formation ¡22], the com plexity of pinealocyte structure and function cannot be fully appreciated unless more data on the presence or absence of SB are available.…”