OBJECTIVE: To evaluate the regulation of the secretion of insulin-like growth factor (IGF) binding proteins (IGFBPs) by FSH in human luteinizing granulosa cells. DESIGN AND RESULTS: Luteinizing granulosa cells were incubated with and without FSH. Levels of IGFBP-1 and -3 in the medium were measured by EIA and RIA, respectively and binding activities of these IGFBP were evaluated by Western ligand blot. FSH inhibited the secretion of IGFBP-1 dose dependently. FSH did not inhibit the secretion of immunoreactive IGFBP-3, but inhibited the binding activity of IGFBP-3. To assess the protease activity, 125I-IGFBP-3 was incubated with the cultured medium. 125I-IGFBP-3 degraded into small fragments when it was incubated with the cultured medium treated with FSH. CONCLUSIONS: FSH enhances the action of IGF-I in human granulosa cells by inhibiting the secretion of IGFBP-1 and the binding activity of IGFBP-3 by stimulating the proteolysis of IGFBP-3.
OBJECTIVE: To evaluate the regulation of the secretion of insulin-like growth factor (IGF) binding proteins (IGFBPs) by FSH in human luteinizing granulosa cells. DESIGN AND RESULTS: Luteinizing granulosa cells were incubated with and without FSH. Levels of IGFBP-1 and -3 in the medium were measured by EIA and RIA, respectively and binding activities of these IGFBP were evaluated by Western ligand blot. FSH inhibited the secretion of IGFBP-1 dose dependently. FSH did not inhibit the secretion of immunoreactive IGFBP-3, but inhibited the binding activity of IGFBP-3. To assess the protease activity, 125I-IGFBP-3 was incubated with the cultured medium. 125I-IGFBP-3 degraded into small fragments when it was incubated with the cultured medium treated with FSH. CONCLUSIONS: FSH enhances the action of IGF-I in human granulosa cells by inhibiting the secretion of IGFBP-1 and the binding activity of IGFBP-3 by stimulating the proteolysis of IGFBP-3.
Authors: Lenka Bruckova; Tomas Soukup; Benjamin Visek; Jiri Moos; Martina Moosova; Jana Pavelkova; Karel Rezabek; Lenka Kucerova; Stanislav Micuda; Eva Brcakova; Jaroslav Mokry Journal: J Assist Reprod Genet Date: 2011-08-06 Impact factor: 3.412