Progesterone inhibits insulin-like growth factor binding protein-1 (IGFBP-1) production by explants of the Fallopian tube.
The Fallopian tube provides the environment for early embryo growth, a process which is influenced by insulin-like growth factors (IGFs) in the tubal fluid. Whether the bioavailability of tubal IGFs is modulated by locally produced IGF-binding protein (IGFBP-1) is not clear. An explant culture system from human Fallopian tube mucosa was, therefore, developed enabling the potential for IGFBP-1 production by this tissue to be examined directly. Initial characterization of the system established that the explants maintained responsiveness to steroids. Thus, oviduct-specific glycoprotein production, a major product of the oviduct in vivo, continued to be made via an estrogen-sensitive pathway in the culture. The presence of mRNA for IGFBP-1 was established within the explants by the use of quantitative RT-PCR and IGFBP-1 protein was measured by enzyme-linked immunosorbent assay. Although insulin and estradiol had no consistent effect on IGFBP-1, addition of progesterone had a significant inhibitory effect on IGFBP-1 production, both at the mRNA and protein levels. A dose-range of progesterone revealed an incremental inhibitory effect of progesterone on IGFBP-1 output (maximal effect, 25-50 nmol/l), consistent with physiological inhibition of this process during the luteal phase. We suggest that progesterone might, therefore, play a role in controlling the bioavailability of IGFs to the embryo during early development within the Fallopian tube.
Davies
S
S
Maternal, Fetal and Neonatal Physiology, Developmental Origins of Health and Disease Division, University of Southampton, Level F (815), Princess Anne Hospital, Coxford Road, Southampton SO16 5YA, UK.
Richardson
M C
MC
Anthony
F W
FW
Mukhtar
D
D
Cameron
I T
IT
D000328:Adult; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000494:pharmacology; D005187:Fallopian Tubes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000096:biosynthesis* / Q000235:genetics; D008875:Middle Aged; D011374:Progesterone / Q000494:pharmacology* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046509:Tissue Culture Techniques
D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol