TY - JOUR
T1 - Insulin-like growth factor I stimulates the synthesis and release of prolactin from human decidual cells
AU - Thrailkill, Kathryn M.
AU - Golander, Avraham
AU - Underwood, Louis E.
AU - Handwerger, Stuart
PY - 1988/12
Y1 - 1988/12
N2 - Recent studies suggest a role for insulin-like growth factor I (IGF-I) in the regulation of hormone release from placental, gonadal, and pituitary tissues. To examine whether IGF-I may also regulate the release of PRL from human decidual tissue, we have investigated the effect of recombinant human IGF-I on PRL release from monolayer cultures of human decidual cells exposed to IGF-I for up to 4 days. IGF-I (10-1000 ng/ml) stimulated a sustained dose-dependent increase in PRL release (half-maximal concentration, 25 ng/ml) beginning 48 h after initial exposure, but had no effect on the intracellular PRL content. The amounts of PRL released from maximally stimulated cultures on days 3 and 4 were 168 ± 3% (mean ± SEM) and 258 ± 8% of control values, respectively. IGF-I-mediated effects were inhibited by cyclohexiinide (3.6 μM), suggesting that the increase in PRL was the result of newly synthesized hormone. The increase in PRL release was not due to a generalized effect on protein release, since IGF-I had no effect on the release of trichloroacetic acid-precipitable [35S]methionyl proteins. Radioligand competition studies indicate that the biological actions of IGF-I are mediated through interaction with the IGF-I receptor. Binding of radiolabeled IGF-I to decidual cells in suspension was specific, saturable, and displacable by unlabeled IGF-I, with a potency nearly 10 times greater than that of insulin. Furthermore, exposure of decidual cells to a monoclonal antibody to the IGF-I receptor (α-IR3) completely inhibited both IGF-I-mediated PRL release and specific binding of [125I]IGF-I to decidual cells. Since the actions of IGF-I occurred at physiological concentrations, these findings strongly support a role for IGF-I in the regulation of PRL secretion by human decidua.
AB - Recent studies suggest a role for insulin-like growth factor I (IGF-I) in the regulation of hormone release from placental, gonadal, and pituitary tissues. To examine whether IGF-I may also regulate the release of PRL from human decidual tissue, we have investigated the effect of recombinant human IGF-I on PRL release from monolayer cultures of human decidual cells exposed to IGF-I for up to 4 days. IGF-I (10-1000 ng/ml) stimulated a sustained dose-dependent increase in PRL release (half-maximal concentration, 25 ng/ml) beginning 48 h after initial exposure, but had no effect on the intracellular PRL content. The amounts of PRL released from maximally stimulated cultures on days 3 and 4 were 168 ± 3% (mean ± SEM) and 258 ± 8% of control values, respectively. IGF-I-mediated effects were inhibited by cyclohexiinide (3.6 μM), suggesting that the increase in PRL was the result of newly synthesized hormone. The increase in PRL release was not due to a generalized effect on protein release, since IGF-I had no effect on the release of trichloroacetic acid-precipitable [35S]methionyl proteins. Radioligand competition studies indicate that the biological actions of IGF-I are mediated through interaction with the IGF-I receptor. Binding of radiolabeled IGF-I to decidual cells in suspension was specific, saturable, and displacable by unlabeled IGF-I, with a potency nearly 10 times greater than that of insulin. Furthermore, exposure of decidual cells to a monoclonal antibody to the IGF-I receptor (α-IR3) completely inhibited both IGF-I-mediated PRL release and specific binding of [125I]IGF-I to decidual cells. Since the actions of IGF-I occurred at physiological concentrations, these findings strongly support a role for IGF-I in the regulation of PRL secretion by human decidua.
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U2 - 10.1210/endo-123-6-2930
DO - 10.1210/endo-123-6-2930
M3 - Article
C2 - 2973977
AN - SCOPUS:0024215003
SN - 0013-7227
VL - 123
SP - 2930
EP - 2934
JO - Endocrinology
JF - Endocrinology
IS - 6
ER -