Dopamine Inhibits the Arachidonate and Prolactin Release Stimulated by Thyrotropin-Releasing Hormone through an Islet-Activating Protein-Sensitive GTP-Binding Protein in Anterior Pituitary Cells

1990 ◽  
Vol 52 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Masahide Ohmichi ◽  
Kenji Hirota ◽  
Koji Koike ◽  
Kozo Kadowaki ◽  
Masaaki Yamaguchi ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Binding Protein ◽  
Thyrotropin Releasing Hormone ◽  
Pituitary Cells ◽  
Gtp Binding Protein ◽  
Prolactin Release ◽  
Releasing Hormone ◽  
Gtp Binding ◽  
Anterior Pituitary Cells

scholarly journals Rab3B is essential for GnRH-induced gonadotrophin release from anterior pituitary cells

1998 ◽  
Vol 157 (2) ◽  
pp. 267-274 ◽  
Author(s):  
K Tasaka ◽  
N Masumoto ◽  
J Mizuki ◽  
Y Ikebuchi ◽  
M Ohmichi ◽  
...  
Keyword(s):  
Antisense Oligonucleotide ◽  
Anterior Pituitary ◽  
Binding Protein ◽  
Physiological Process ◽  
Pituitary Cells ◽  
Gtp Binding Protein ◽  
Regulated Exocytosis ◽  
Releasing Hormone ◽  
Gtp Binding ◽  
Gonadotrophin Releasing Hormone

Gonadotrophin-releasing hormone (GnRH) induces the release of gonadotrophins via an increase in cytosolic Ca2+ concentration ([Ca2+]). Rab3B, a member of the small GTP-binding protein Rab family, is known to be involved in Ca(2+)-regulated exocytosis in pituitary cells. However, it is not known whether Rab3B functions in the physiological process regulated by GnRH in gonadotrophs. In this study using antisense oligonucleotide against Rab3B (AS-Rab3B) we determined that Rab3B is involved in GnRH-induced gonadotrophin release. Rab3B immunopositive cells were reduced in 24% of pituitary cells by AS-Rab3B. This treatment did not affect the population of gonadotrophs or the intracellular contents of gonadotrophins. However, AS-Rab3B significantly inhibited the total amount of basal and GnRH-induced gonadotrophin released from pituitary cells. These results show that Rab3B is involved in basal and GnRH-induced gonadotrophins release but not the storage of gonadotrophins. Next, the changes in [Ca2+] and exocytosis in gonadotrophs treated with AS-Rab3B were compared among Rab3B-positive and -negative cells. The change in [Ca2+] was not different in the two groups, but exocytosis was significantly inhibited in Rab3B-negative cells. These results suggest that Rab3B is essential for GnRH-regulated exocytosis downstream of cytosolic Ca2+ in gonadotrophs.

Thyrotropin-Releasing Hormone Gene Expression in Cultured Anterior Pituitary Cells: Role of Gender

1995 ◽  
Vol 61 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Thomas O. Bruhn ◽  
Jan M.M. Rondeel ◽  
Thomas G. Bolduc ◽  
Ivor M.D. Jackson
Keyword(s):  
Gene Expression ◽  
Anterior Pituitary ◽  
Thyrotropin Releasing Hormone ◽  
Pituitary Cells ◽  
Releasing Hormone ◽  
Anterior Pituitary Cells
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