Immunochemical detection of growth hormone and prolactin cells in the pituitary gland of the mountain frog (Rana blythii)

Abstract

Immunocytochemistry and immunogold techniques were employed to classify and localize the cell producing growth hormone (GH) and prolactin (PRL) in the pars distalis of the mountain frog (Rana blythii) pituitary. The pituitary glands obtained from mature frogs during the breeding season (November-February) were fixed in Bouin's fluids for an immunocytochemical study, and in 0.2% glutaraldehyde, 2% paraformaldehyde, and 0.5% picric acid in 0.05M Millonig's phosphate buffer pH 7.4 at 40C for an immunogold study. By immunocytochemical study, GH immunoreactive cells appeared as round or oval shaped, concentrated mainly in the dorso-posterior region of pars distalis. PRL immunoreactive cells were elongated in shape and scattered throughout the pars distalis. By immunogold technique, GH cells were identified by the presence of lipid droplets and contained three types of granules; round-shaped (356.2±4.1 nm in diameter), rod-shaped (196.1±4.1 nm in width and 345.6±5.3 nm in length), and irregular shaped (139.5-310.8 nm in width and 223.3-459.7 nm in length). PRL cells exhibited round granules of moderate electron density (355.2±5.3 nm in diameter).