In vivo and in vitro evidence of growth hormone-releasing factor-like produced locally in the adenohypophyseal cells of the rat.
In order to characterize immunocytochemically the existence of GRF in the rat adenohypophysis and the origin of this hormone, an immunocytochemical and morphometric study was made of r-GRF-immunoreactive cells from the adenohypophysis of untreated adult rats, adult rats treated intraventricularly with colchicine and in primary cultures of adult rat adenohypophyseal cells that had been incubated with serum devoid of GRF. r-GRF immunoreactive cells were observed in untreated rat pituitaries, both male and female, although the numbers of positive cells were greater in the males (p less than 0.05) and were found to increase in number following treatment with colchicine (p less than 0.01). These cells appeared dispersed throughout the anterior lobe, without forming clusters, and were often close to blood vessels. Additionally, immunoreactive cells appeared in the cultures at 7 days of incubation. The presence of GRF-immunoreactive cells in the adenohypophysis of rats previously treated with colchicine suggests the existence of a non-hypothalamic origin for r-GRF; this is confirmed by the findings obtained in the in vitro studies which would corroborate the hypothesis that the origin of the neuropeptide is in the rat adenohypophysis itself.
Carretero
J
J
Department of Human Anatomy and Histology, Faculty of Medicine, University of Salamanca, Spain.
Sánchez
F
F
Vázquez
R
R
Cacicedo
L
L
Sánchez-Franco
F
F
Fernández
G
G
Montero
M
M
D000818:Animals; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000032:analysis* / Q000276:immunology; D007150:Immunohistochemistry; D008297:Male; D010903:Pituitary Gland, Anterior / Q000737:chemistry* / Q000187:drug effects; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013194:Staining and Labeling
D013007:Growth Hormone-Releasing Hormone; D003078:Colchicine