Localization of the N-methyl-D-aspartate R-1 receptor in the pituitary gland of immature rainbow trout (Oncorhynchus mykiss)

A study was conducted on the selective immunostaining of pituitary cells an d pars nervosa of immature rainbow trout by antibody raised against the R-1 subunit of the rat ionotropic N-methyl-D-aspartate (NMDA) receptor. In the pars distalis, the mammotrophs of the rostral pars distalis exhibited the most marked imunoreactivity, with the somatotrophs of the proximal pars dis talis showing a consistently lower degree of immunoreactivity. No imunoreac tivity was associated with the corticotrophs, thyrotrophs or gonadotrophs. In the pars intermedia, the melanotrophs showed no evidence of immunoreacti vity, whereas the putative somatomammotrophs exhibited a wide inter-animal range of immunoreactivity. Some imunostaining was also evident in the anter ior and posterior part of the pars nervosa, at the interface of the pars di stalis or pars intermedia with the pars nervosa.