ISSN:
1040-452X
Keywords:
IGF-1
;
Inner cell mass
;
Trophectoderm
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Because recent studies have particularly implicated the insulin growth factor family in early development, the effects of insulin-like growth factor (IGF-1) on the development of mouse embryos in vitro were investigated in detail. When added to the medium for culture of two-cell embryos, IGF-1 stimulated the number of cells in the resultant blastocysts after 54 hr, entirely by increasing the number of cells in the inner cell mass (ICM) (16.0 ± 0.5 vs. 12.6 ± 0.5 cells/ICM). This stimulation was also achieved when ICMs were isolated from blastocysts prior to culture for 24 hr with IGF-1 (22.3 ± 1.0 vs. 17.5 ± 0.8 cells/ICM). There was no effect of IGF-1 on trophectoderm (TE) cell proliferation. In morphology studies, IGF-1 also increased the proportion of blastocysts (62% ± 3% vs. 49% ± 4%) while decreasing the number of embryos remaining as morulae (32% ± 3% vs. 38% ± 2%) or in the early cleavage stages (7% ± 3% vs. 13% ± 3%) after 54 hr culture from the two-cell stage. All these effects were achieved with EC50s of approximately 60 pM IGF-1, which is in the range for IGF-1 receptor mediation; however, cross reaction with insulin, IGF-2, or other unknown receptors is not excluded. Nonetheless, the results show that physiological concentrations of IGF-1 (17-170 pM, 0.1-1 ng/ml), which have been observed in the reproductive tract, affect the early embryo, suggesting a normal role for this factor in the regulation of growth of the developing conceptus before implantation.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1080310306
Permalink
