Regulation of IGF-I and porcine oviductal secretory protein (pOSP) secretion into the pig oviduct in the peri-ovulatory period, and effects of previous nutrition.

The mechanisms regulating oviduct function were investigated. In Experiment 1, porcine oviductal secretory protein (pOSP) mRNA, and pOSP and insulin-like growth factor (IGF-I) in oviductal flushings, decreased through the peri-ovulatory period. In Experiment 2, higher plasma steroids in oviductal veins, ipsilateral (INT), rather than contralateral (OVX), to the remaining ovary in unilaterally ovariectomized gilts, were associated with higher pOSP in INT oviductal flushings. In Experiment 3, oviduct function was assessed as part of a collaborative study in cyclic gilts. Feed restriction in the late, compared to the early, luteal phase reduced estradiol concentrations in oviductal plasma, pOSP mRNA in oviductal tissue, and IGF-I concentrations and pOSP abundance in oviduct flushings. Previous insulin treatment differentially affected oviduct function. These data provide the first direct evidence for effects of previous feed restriction and insulin treatment on the oviduct environment in the peri-ovulatory period, which may contribute to nutritional effects on embryonic survival.