Growth hormone and in vitro maturation of rhesus macaque oocytes and subsequent embryo development

Purpose: The objective of this study was to use a nonhuman primate model to examine the effects of growth hormone (GH) on oocyte in vitro maturation (IVM). Methods: Immunocytochemistry confirmed the presence of GH receptors in rhesus cumulus oocyte complexes and the cytoplasm of embryonic blastomeres. Recombinant human GH (r-hGH) was added to IVM medium and cumulus expansion, nuclear maturation, cytoplasmic maturation and embryo development were analyzed. Results: Cumulus expansion was highest in the presence of 1 and 10 ng/ml r-hGH. The addition of r-hGH during IVM increased the percentage of embryos progressing to at least the 9-16 cell stage. In a separate study, 100 ng/ml r-hGH was supplemented to IVM and embryo culture medium and no effect was observed. Conclusions: The presence of GH receptors along with increased cumulus expansion and embryos progressing to the 9-16 cell stage supports the hypothesis that r-hGH may be involved in oocyte maturation.