The effect of the angiogenesis inhibitor TNP-470 on luteal establishment and function in the primate

Angiogenesis during luteal development is probably essential for normal lutein cell function. Since the angiogenesis inhibitor TNP-470 inhibits pregnancy in mice, the current study investigated its effects on the establishment and function of the primate corpus luteum. Regularly ovulating macaques were treated with TNP-470 (6 mg/kg), i.v. in three doses, 48 h apart. Serum progesterone concentrations, as indicators of treatment effect, were normal in four macaques where treatment commenced at the onset of the ovulatory progesterone rise, and in five of eight in which treatment commenced a few days before ovulation. In the other three the normal progesterone rise was absent. To investigate the direct effect on luteal angiogenesis of a daily dose over a longer period, four marmosets received 18 mg/kg/day of TNP-470 i.v. for 9 days starting at ovulation. On day 10, luteal cell proliferation was determined by nuclear bromodeoxyuridine incorporation. Luteal microvasculature was examined using immunocytochemical factor VIII staining, and endothelial cell and luteal function assessed by in-situ hybridization of insulin-like growth factor binding protein-3 mRNA and plasma progesterone concentrations respectively. None of these parameters were affected by the TNP-470 treatment. The results show that, with the treatment regimens employed, TNP-470 had no significant effect on the expression of the differentiated state of the primate corpus luteum.