IMMUNOCYTOCHEMICAL LOCALIZATION OF THE PIT-1 PROTEIN IN THE PITUITARYOF THE RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

Pit-1 is a pituitary-specific transcription factor responsible for act ivating the growth hormone (GH) gene family. The localization of Pit-1 protein in the pituitary of rainbow trout was studied by immunocytoch emical analysis. Fish Pit-1 was found to be extensively localized in t he nuclei of cells in the proximal pars distalis (PPD), rostral pars d istalis (RPD), and pars intermedia (PI). Sagittal sections were immuno cytochemically double stained with antibodies against Pit-1, GH, prola ctin (PRL), and somatolactin (SL). The results showed that Pit-1 prote in was present in the GH-containing cells of the PPD, the PRL-containi ng cells of the RPD, and the SL-containing cells of the PI. (C) 1996 A cademic Press, Inc.