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Effects of thyroliberin (TRH) on cell proliferation and prolactin secretion by GH3/B6 rat pituitary cells: A comparison between serum‐free and serum‐supplemented media
Author(s) -
Brunet N.,
Rizzino A.,
Gourdji D.,
TixierVidal A.
Publication year - 1981
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041090220
Subject(s) - prolactin , medicine , endocrinology , thyrotropin releasing hormone , prolactin cell , secretion , stimulation , hormone , chemistry , chemically defined medium , biology , in vitro , biochemistry
Numerous studies have shown that prolactin (PRL) production by GH 3 cells grown in serum supplemented media is regulated by several hormones including thyroliberin (TRH). The recent availability of hormonally defined, serum‐free media for the growth of GH 3 cells has made it possible to determine the effect of TRH in absence of other prolactin regulating hormones. Here we demonstrate that transfer of GH 3 /B 6 cells from serum‐supplemented medium to serum‐free media results in several important changes: (1) altered growth response to TRH, (2) altered cell attachment and morphology, (3) greatly reduced prolactin production, and (4) greater stimulation of prolactin production by TRH. After 4 days in serum‐free medium, TRH stimulates prolactin production by as much as 5‐fold instead of approximately 2‐fold in serum‐supplemented medium. Furthermore, this increased responsiveness to TRH in serum‐free medium is accompanied by a 10‐fold decrease in the ED 50 for TRH (concentration needed for half‐maximal response) and paradoxically by a 2‐fold reduction in the number of high‐affinity TRH binding sites without significant change of their association constant.