scholarly journals Alpha-transforming growth factor secreted by untransformed bovine anterior pituitary cells in culture. I. Purification from conditioned medium.

1986 ◽  
Vol 261 (31) ◽  
pp. 14408-14413 ◽  
Author(s):  
J Samsoondar ◽  
M S Kobrin ◽  
J E Kudlow
Keyword(s):  
Growth Factor ◽  
Conditioned Medium ◽  
Anterior Pituitary ◽  
Transforming Growth Factor ◽  
Pituitary Cells ◽  
Cells In Culture ◽  
Anterior Pituitary Cells

Inhibin bioactivity and pituitary cell mitogenic activity from cultured chicken ovarian granulosa and thecal/stromal cells

1988 ◽  
Vol 116 (2) ◽  
pp. 293-299 ◽  
Author(s):  
C. G. Tsonis ◽  
P. J. Sharp ◽  
A. S. McNeilly
Keyword(s):  
Growth Factor ◽  
Conditioned Medium ◽  
Anterior Pituitary ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Pituitary Cells ◽  
Mitogenic Effect ◽  
Anterior Pituitary Cells ◽  
Domestic Hen

ABSTRACT A sensitive bioassay for inhibin based on the suppression of FSH release from cultured sheep anterior pituitary cells was used to determine whether inhibin is present in the preovulatory follicle in the domestic hen. Granulosa and thecal/stromal layers were separated from the five largest (F1–F5) yellow yolky follicles in the ovary and incubated in culture medium for 18 h. Inhibin was found predominantly in the media in which granulosa layers had been incubated. There was a progressive increase in the amount of inhibin produced per mg granulosa layer protein during the 5–6 days before ovulation. The ovary was observed to contain a growth factor which stimulated the proliferation of ovine pituitary cells. Thecal/stromal layer-conditioned medium (ThCM) but not granulosa layer-conditioned medium had a dose- and time-dependent mitogenic effect on cultured sheep pituitary cells. The maximal mitogenic effect achieved for ThCM was four to fivefold greater than control media and was significantly higher than the maximal mitogenic effects of epidermal growth factor (250 ng/ml; 1·5 × control) and transforming growth factor-β (500 ng/ml; 1·2 × control). It is concluded that inhibin is produced by the granulosa layers in the large yellow yolky preovulatory ovarian follices of the domestic hen. The thecal/stromal layers in these follicles produce a potent mitogenic factor, not produced by the granulosa layers, which stimulates the division of ovine anterior pituitary cells in vitro. J. Endocr. (1988) 116, 293–299

The effects of insulin-like growth factor-I (IGF-I), IGF-II and des(1–3)IGF-I, a potent IGF analogue, on growth hormone and IGF-binding protein secretion from cultured rat anterior pituitary cells

1991 ◽  
Vol 130 (1) ◽  
pp. 93-99 ◽  
Author(s):  
J. M. Simes ◽  
J. C. Wallace ◽  
P. E. Walton
Keyword(s):  
Growth Factor ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Gh Secretion ◽  
Factor I ◽  
Anterior Pituitary Cells ◽  
Low Concentrations ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein

ABSTRACT The effects of insulin-like growth factor-I (IGF-I), IGF-II and des(1–3)IGF-I, a potent IGF-I analogue, on the secretion of GH and IGF-binding protein (IGFBP) from cultured rat anterior pituitary cells were measured. IGF-I and des(1–3)IGF-I stimulated GH secretion at low concentrations (maximally effective at 1 and 0·1 μg/l respectively) and inhibited GH secretion at higher concentrations. The half-maximal inhibitory concentrations (IC50) were approximately 20 μg/l and 1 μg/l for IGF-I and des(1–3)IGF-I respectively. Thus des(1–3)IGF-I was more potent than IGF-I in these effects on GH secretion. We postulate that the increased potency of des(1–3)IGF-I in affecting GH secretion is due to decreased binding of this peptide by pituitary IGFBP compared with IGF-I. In contrast with IGF-I and des(1–3)IGF-I, IGF-II did not stimulate GH secretion at low concentrations, but did inhibit GH secretion from pituitary cells with an IC50 of approximately 20 μg/l. Several IGFBPs ranging in molecular mass from 22 000 to 52 000 were detected in medium conditioned by cultured anterior pituitary cells. When measured by Western-ligand blotting and competitive ligand-binding techniques, these IGFBPs exhibited decreased binding of des(1–3)IGF-I compared with IGF-I and IGF-II. The production of IGFBP by anterior pituitary cells was stimulated by the addition of IGFs to the culture medium. Journal of Endocrinology (1991) 130, 93–99

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