Characterization of activin A-, activin AB- and activin B-responding cells by their responses to hypothalamic releasing hormones.
Activin A-, AB- and B-responding cells were characterized by their responsiveness in cytosolic free calcium ([Ca2+])i) to four hypothalamic releasing hormones, CRH, GHRH, TRH and GnRH. First, rat pituitary cells responding to activin A, AB and B in [Ca2+]i were determined in a mixed population of pituitary cells. The populations of the activin A-, AB-, and B-responding cells were 13.9%, 9.3% and 13.2%, respectively. Overlapping of response among each population of activin- responding cells was present in some of the cells. The cells responding to activin A, AB, and B were then characterized by their responses to CRH, GHRH, TRH and GnRH. Most of the cells responding to activin A, AB, and B also responded to GHRH or TRH. These results reveal that there are distinct differences among each population of activin A-, AB- and B-responding cells and that there is still functional overlapping of responsiveness among these populations. The characterization of activin-responding cells suggests involvement of somatotropes and lactotropes in activin-induced biological events in the pituitary.
Tasaka
K
K
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Kasahara
K
K
Masumoto
N
N
Mizuki
J
J
Fukami
K
K
Miyake
A
A
Nakamura
T
T
Sugino
H
H
D028341:Activins; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D007265:Inhibins / Q000494:pharmacology*; D007700:Kinetics; D009842:Oligopeptides; D010455:Peptides / Q000494:pharmacology*; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D013997:Time Factors
D006133:Growth Substances; D009842:Oligopeptides; D010455:Peptides; D010906:Pituitary Hormone-Releasing Hormones; C044147:activin B; D028341:Activins; C048617:myelopeptides; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D013973:Thyrotropin-Releasing Hormone; D003346:Corticotropin-Releasing Hormone; D013007:Growth Hormone-Releasing Hormone; D002118:Calcium