Pituitary gland of a hillstream sisorid catfish, Pseudecheneis sulcatus (McClelland)

Pituitary gland of a hillstream sisorid catfish, Pseudecheneis sulcatus has been studied light microscopically. The pituitary is suspended from the hypothalamus by a slender infundibular stalk which enters the gland antero-dorsally, giving rise to the dorso-elptobasic condition. The pituitary is demarcated into pars nervosa, rostral pars distalis, proximal pars distalis and pars intermedia regions. Pars nervosa is formed of neurosecretory fibres which ramify extensively in the pars intermedia. The rostral pars distalis has predominantly acidophils which are arranged in rosettes. Proximal pars distalis has cyanophils, acidophils and few chromophobes while only acidophils and cyanophils are present in the pars intermedia. Sparse cyanophils and chromophobes are also present in the rostral pars distalis. The acidophils of proximal pars distalis are of two types which differ in tinctorial and morphological characteristics, from the acidophils of rostral pars distalis. The cyanophils are positively stained with AF, AT, PAS and aniline blue.