Growth hormone-releasing factor (GRF) suppresses the in vitro proliferation of mammotrophs from the adult rat.
In order to examine the hypothalamic control of acidophilic proliferation, anterior pituitary cells from adult female rats were cultured with or without rat growth hormone-releasing factor fragment 1-29 (GRF-29). Changes in the numbers of mammotrophs and somatotrophs during culture were measured by immunocytochemical staining. The addition of GRF suppressed the increase in the number of mammotrophs even at the very low concentration of 10(-12) M. The number of somatotrophs increased in the medium containing GRF. The increase in mammotroph number was blocked by cytosine arabinoside, a mitotic inhibitor. GRF had no effect on the in vitro proliferation of fibroblasts. These results indicate the important role of hypothalamic GRF in the differential growth and secretion of the acidophils in vivo.
Shinkai
T
T
Department of Regulation Biology, Faculty of Science, University of Saitama, Urawa, Japan.
Ooka
H
H
Noumura
T
T
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D007700:Kinetics; D010446:Peptide Fragments / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000166:cytology* / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D010446:Peptide Fragments; D013007:Growth Hormone-Releasing Hormone; C059148:somatotropin releasing hormone (1-29)