Intrauterine progestin induces continuous insulin-like growth factor-binding protein-1 production in the human endometrium.
The effect of local intrauterine progestin on endometrial insulin-like growth factor-binding protein-1 (IGFBP-1) production was studied in 60 women using a levonorgestrel-releasing intrauterine device (IUD). Intrauterine progestin was a potent stimulator of stromal cell IGFBP-1 production, with 97% of endometrial specimens showing positive staining by immunohistological methods. After 5 yr or more of intrauterine progestin exposure, 100% (n = 20) of the tissues remained strongly positive for IGFBP-1. The IGFBP-1 content in endometrial tissue homogenates reached values as high as 10 micrograms/mg protein when measured by immunoradiometric assay. In contrast to the continuous endometrial IGFBP-1 production induced by local progestin, no such effect could be found in endometria from subjects with sc progestin-releasing implants or copper IUDs. Although the levonorgestrel-releasing IUD had a striking effect on local endometrial IGFBP-1 production, it had no effect on serum IGFBP-1 levels. By Western ligand blot analysis, the domainating IGF-binding species in endometria exposed to intrauterine progestin was of 28K mol wt, corresponding to IGFBP-1, whereas no IGFBP species of 31-43K, corresponding to IGFBP-2 or IGFBP-3, were detected.
Pekonen
F
F
Minerva Foundation Institute for Medical Research, Helsinki, Finland.
Nyman
T
T
Lähteenmäki
P
P
Haukkamaa
M
M
Rutanen
E M
EM
D000328:Adult; D002352:Carrier Proteins / Q000096:biosynthesis*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D018970:Insulin-Like Growth Factor Binding Protein 1; D007434:Intrauterine Devices; D016912:Levonorgestrel / Q000008:administration & dosage* / Q000494:pharmacology; D009994:Osmolar Concentration; D013002:Somatomedins / Q000096:biosynthesis; D013194:Staining and Labeling
D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D013002:Somatomedins; D016912:Levonorgestrel