AN IMMUNOCYTOCHEMICAL STUDY OF PITUITARY-CELLS OF THE SENEGALESE SOLE, SOLEA-SENEGALENSIS (KAUP 1858)

Different antisera directed against mammalian and piscine pituitary ho rmones, as well as a battery of various conventional histochemical tec hniques (PAS, Alcian Blue pH 2.5, Bromophenol Blue) and lectins, were used to identify the different hormonal cell types in the pituitary of the Senegalese sole, Solea senegalensis. Prolactin and adrenocorticot rophic cells were located in the rostral pars distalis of the pituitar y. Gonadotrophic, thyrotrophic and growth hormone cells were distribut ed in the proximal pars distalis, but gonadotrophic cells appear also at the border of the pars intermedia. Somatolactin cells, as well as a lpha-melanotrophic cells were located in the pars intermedia of the So lea senegalensis pituitary. The PAS reaction was positive in somatolac tin cells, which were unreactive with the lead-Haematoxylin technique, whereas melanotrophic cells were positive. Glycoproteins containing m annose and/or glucose, as well as N-acetyl-glucosamine and sialic acid sugar residues, are synthesized and secreted by gonadotrophic, thyrot rophic and somatolactin cells. Adrenocorticotrophic cells and, especia lly, the amphiphilic somatolactin and acidophilic growth hormone cells were stained with the Bromophenol Blue technique that identifies prot eins in general, but adrenocorticotrophic and growth hormone cells wer e unreactive towards PAS, Alcian Blue pH 2.5 and lectins (Con A and WG A).