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The effects of epidermal growth factor on cell proliferation and prolactin production by GH 3 rat pituitary cells
Author(s) -
Yajima Yukiko,
Saito Toshikazu
Publication year - 1984
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.1041200220
Subject(s) - epidermal growth factor , prolactin , internalization , endocrinology , medicine , receptor , cell culture , cell growth , biology , incubation , cell , growth factor , chemically defined medium , microbiology and biotechnology , chemistry , hormone , in vitro , biochemistry , genetics
The effects of epidermal growth factor (EGF) were studied in rat pituitary tumor cells, GH 3 , grown in serum‐supplemented and serum‐free chemically defined media. EGF (1 nM) increased the cell number to 132% of the control cultured in the defined medium during a 6‐day incubation period, while it decreased the cell number to 60% of the control in the serum‐supplemented medium. EGF altered the morphology of the cells grown in the defined medium more markedly to an elongated conformation than that of cells grown in the serum‐supplemented medium. EGF also stimulated prolactin (PRL) production by culture in the presence or absence of serum. The effects of the cell density of GH 3 on the action of EGF were shown to appear in two ways. The mitogenic influence of EGF was more effective on, and more responsive to, high‐density cells, whereas the stimulatory action on PRL production was less effective on high‐density cells. However, the inhibitory effects on cellular growth appeared independently of cell densities. The results obtained with 125 I‐EGF binding experiments indicated that the number of binding sites, affinity, and internalization of EGF receptors were similar in either serum‐supplemented or serum‐free culture. At low cell density, the number of available 125 I‐EGF binding sites per cell was larger than at high cell density. These results suggested that there was no apparent correlation between EGF binding and its differing effects on the growth of GH 3 cultured in the serum‐supplemented and the defined medium.