title: Seasonal plasticity of the pituitary pars intermedia of the one-humped camel (Camelus dromedarius).
abstract: The pituitary pars intermedia of Camelus dromedarius is well developed and completely surrounds the pars nervosa. Two major groups of cells are present: endocrine (ec) and glial-like cells (glc). The ec group is composed of three morphologically distinct cell types. Type I, or polyhedral light cells (LC-I) and type II, or polyhedral dark cells (DC-II), have secretory granules of heterogeneous electron density whose size ranges from 170 to 300nm. Type III cells are elongated with homogeneous electron-dense secretory granules of 80-200nm. The glc make up an organized network, form follicles in the centrolobular zones and are positive for vimentin and S-100β immunolabelling. The nerve fibres penetrating the lobe are numerous, and can be classified into two types according to the membrane bound vesicles found in their endings (ne). Ultrastructural quantitative analysis revealed significant variations in PI elements between winter and summer seasons (F=8.014, p=0.006). DC-II cells characterized by developed biosynthetic machinery and a large pool of secretory granules storage are increased with the ne in winter. However, LC-I cells showing frequent cytoplasmic degranulation are predominant with glc in summer. Thus, important cellular remodelling occurs in the dromedary PI that may depend upon, or perhaps anticipate, external living conditions.
authors.affiliation: Université Saad Dahleb, Département des Sciences Agro-Vétérinaires et Biologiques, B.P. 270, route de Soumaa Blida, Algeria; Laboratoire d'Éco-Biologie Animale (L.E.B.A.); École Normale Supérieure de Kouba Bachir El Ibrahimi, B.P. 92, Algiers 6050, Algeria. Electronic address: zahralim@yahoo.com.
authors.forename: F Z
authors.initials: FZ
authors.lastname: Djazouli Alim
authors.affiliation: Laboratoire d'Éco-Biologie Animale (L.E.B.A.); École Normale Supérieure de Kouba Bachir El Ibrahimi, B.P. 92, Algiers 6050, Algeria.
authors.forename: N
authors.initials: N
authors.lastname: Lebaili
authors.affiliation: Unitat de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut d'Investigacións Biomèdiques (IDIBAPS), Universitat de Barcelona, CIBERNED, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Mahy
mesh_terms: D000818:Animals; D002162:Camelus; D003593:Cytoplasm / Q000648:ultrastructure*; D008297:Male; D009457:Neuroglia / Q000648:ultrastructure*; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000648:ultrastructure*; D015388:Organelles / Q000648:ultrastructure; D052716:Pituitary Gland, Intermediate / Q000294:innervation / Q000648:ultrastructure*; D012621:Seasons
keywords: Morphology; One-humped camel; Pars intermedia; Seasonal variations