Presence of pigment in the ovine pineal gland during embryonic development

Abstract

Light- and electron-mi croscopi c analyses were used 10 id entify and desc ribe th e charac teristi c features of cells containing pigment in the ov ine pineal gland during prenatal deve lopment. 72 ov ine embryos (36 male, 36 female) ranging in age from 54 to 150 days were used fo r this study. Ce lls co nt aining pigment granules were a constant fea ture in this gland . Wh en samples from the di f'ferent groups were inspected using the naked eye, the detection of pigment was of 61 % in groups I (54 to 67 days of prenatal development) and II (7 1 to 92 days of prenatal development), ~3 % in group III (9t; to 113 days of prenatal development) and 25% in gro up IV (II R to 150 days of prenatal deve lopment). The morphologica l featu res and histochemical properties of the pineal pigment enab led it to be identified as me lanin . Several types o f pigme nt granules were ultrastru cturall y distinguished; th ese varied in size, shape and loca tion within pinea l cell populations. The pigment g ranul es were de tec ted in pine alocy te s, interstitial cells and pigmented ce lls. The largest amount and the widest variety of pigmented granules were found in pigment ed ce lls. The prese nce of cells containing pigmented gra nules amongst the cell populations of the developing ov in e pineal gland was a nal ysed a nd compared with that of other mammalian species.