Expression of insulin-like growth factor 1 (IGF-1) in the bovine oviduct during the oestrous cycle.

Growth factors are known to take part in the regulation of reproduction. Here we present evidence for the expression of insulin-like growth factor 1 (IGF-1) in the bovine oviduct. Two IGF-1 specific mRNA-transcripts of 1.5 and 4.4 kb were detected during the whole oestrous cycle, and showed increased expression after ovulation. Complete homology to the known IGF-1 sequence was achieved by specific RT-PCR (reverse transcription-polymerase chain reaction) amplification followed by dideoxysequencing of this 210 bp fragment. IGF-1 protein was localized in the secretory cells of the oviduct epithelium using immunohistochemical techniques. We suggest possible effects of IGF-1 during ovulation either on the oviductal cells or on the early embryo.