title: [Influence of the photoperiod on the ultrastructure of the pineal gland before and during the seasonal genital cycle in the female garden dormouse (Eliomys quercinus L.) (author's transl)].
abstract: The pinealocyte of the female garden dormouse presents ultrastructural characteristics correlated with the sexual cycle. In winter, during the period of sexual quiescence, the pinealocyte is very rich in liposomes, myelinic bodies and lysosomes; the same holds during the summer quiescence state. These organelles and a great number of intracellular vacuoles are very well developed in dormice artificially maintained in anoestrous during the normal sexual activity period by light deprivation. In spring liposomes are strongly reduced in animals that are awake and sexually active, whereas the number of "synaptic ribbons" and of densecored vesicles increases. This ultrastructural aspect can be obtained during winter quiescence in animals living at 22 degrees C, under continuous light, and showing early sexual activation. If illumination is prolonged over the seasonal sexual phase dilated cisterns of granular endoplasmic reticulum, filled with proteinaceous material, appear in the cell. It seems that light no more activates, but inhibits gonadostimulator mechanisms. The pinealocyte's ultrastructural elements which are characteristic of a definite sexual state generally develop before this state is fully established. Actually, the functional significance of these organelles is not known.
mesh_terms: D000818:Animals; D004971:Estrus; D005260:Female; D008029:Lighting; D008081:Liposomes; D008247:Lysosomes / Q000648:ultrastructure; D010870:Pineal Gland / Q000648:ultrastructure*; D011247:Pregnancy; D012270:Ribosomes / Q000648:ultrastructure; D012377:Rodentia / Q000502:physiology*; D012621:Seasons; D013696:Temperature
chemical_list: D008081:Liposomes
vernacular_title: Influence de la photopériode sur l'ultrastructure de l'épiphyse avant et pendant la phase génitale saisonnière chez la femelle du lérot (Eliomys quercinus).