ɪɾ ɛnhˈænsᵻz dˌiːdˈiː ˈaɪ, ænd tʊ ɐ lˈɛsɚɹ ɛkstˈɛnt ˌeɪzˌiːtˈiː ænd dˌiːdˈiː sˈiː. wˈʌn pˈɑːsᵻbəl ɛksplɐnˈeɪʃən ɪz ðæt ˌeɪtʃjˈuː kˈɔːzᵻz sˈɛlz tə spˈɛnd mˈoːɹ tˈaɪm ɪnðə "ˈɛs" fˈeɪz tʃˈɛkpɔɪnt ʌv sˈɛljʊlɚ ɡɹˈoʊθ wˌɪtʃ ɐlˈaʊz dˌiːdˈiː ˈaɪ, ˌeɪzˌiːtˈiː ænd dˌiːdˈiː sˈiː ˌɪntʊ ðə sˈɛl mˈoːɹ.
It enhances ddI, and to a lesser extent AZT and ddC. One possible explanation is that HU causes cells to spend more time in the "S" phase checkpoint of cellular growth which allows ddI, AZT and ddC into the cell more.