Exposure to androgens during in vitro maturation does not affect the developmental potential of porcine oocytes

Administration of exogenous androgens to pigs during the period of follicular development has been shown to positively affect ovulation rate and embryonic survival. The mechanisms of these actions are not known, but may include direct effects of androgens on the cumulus-oocyte complex (COC). The objective of this experiment was to assess the effects on embryonic development in vitro of exposure of COC to 0.26 and 2.6 microM testosterone (T) or dihydrotestosterone (DHT) during IVM. For IVM, COC were cultured for 44-46 h in protein-free tissue culture medium (TCM) 199 containing 10 IU/ml hCG and eCG and 10 ng/ml EGF. Oocytes were then stripped of cumulus cells, coincubated with 1 x 10(5) sperm/ml in modified TALP for 6 h, and cultured for 8 days in NCSU23. The proportions of oocytes that cleaved (Day 2) or developed to the morula (Day 6) or blastocyst (Day 6-8) stage were not different (P > 0.20) between oocytes exposed to androgens and oocytes not exposed to androgens. These results indicate that exposure to androgens during IVM does not affect the ability of oocytes to cleave or develop up to the blastocyst stage in vitro.