Identification of neurotensin-immunoreactive cells in the anterior pituitary of normal and castrated rats. A double immunocytochemical investigation at the light- and electron-microscopic levels.
The localization of neurotensin (NT) has been studied in the rat pituitary by means of immunocytochemistry at the light- and electron-microscopic levels. Cells immunoreactive for NT (NT-IR) were observed in the anterior lobe of rats of both sexes. Following an elution-restaining procedure, it was found that most of these NT-IR cells correspond to cells also reacting to beta-LH or FSH antisera. However, a few NT-IR cells did not stain for beta-LH nor FSH, but for TSH. The subcellular localization of NT was studied at the electron-microscopic level by means of the immunogold procedure. The immunoreactivity was always localized over the secretory granules. By using two sizes of gold particles, it was shown that NT- and beta-LH-IR were colocalized in part of the cell granules. Castration caused a progressive decrease of the NT-IR in the beta-LH- or FSH-positive cells, while the number of NR-IR, TSH-IR cells increased. After 2 weeks, NT-IR was mainly observed in this latter cell type. The present work demonstrates that NT-IR is localized within the secretory granules of the gonadotrophs and a few thyrotrophs, indicating that NT could be released together with gonadotrophins and TSH. Moreover, since gonadectomy results in typical qualitative and quantitative changes of NT-IR gonadotrophs, the intervention of the pituitary NT in the regulation of the hypophysogonadal axis is strongly suggested.
Bello
A R
AR
Area de Biología Celular, Facultad de Biología, Universitad de la Laguna, España.
Dubourg
P
P
Kah
O
O
Tramu
G
G
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009496:Neurotensin / Q000032:analysis*; D009919:Orchiectomy; D010903:Pituitary Gland, Anterior / Q000737:chemistry*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013737:Testis / Q000502:physiology*
D009496:Neurotensin