The effects of lipoxygenase products on progesterone and prostaglandin production by human corpora lutea.

The present study was undertaken to assess the effects of the products of the lipoxygenase pathway on steroidogenesis and the production of prostaglandins (PGs) by human corpora lutea in the midluteal phase. In the first experiment luteal cells were cultured with 5-hydroxyeicosatetraenoic acid (5-HETE) at 10, 100, 500, or 1000 ng/mL in the presence or absence of hCG at 100 ng/mL for 10 days. The addition of 5-HETE dose-dependently inhibited progesterone (P) production by the cultural luteal cells. P production stimulated by exposure to hCG was also reduced significantly in response to 5-HETE. However, 5-HETE had no effect on the production of 6-keto-PGF1 alpha, PGF2 alpha, or PGE2 by cultured luteal cells at any point during the culture period. In the second experiment the reaction products of soybean lipoxidase of arachidonic acid (AA-LIP) were added to cultured luteal cells. Treatment with either AA or LIP alone had no effect on basal P production. The addition of AA-LIP at all concentrations tested reduced P production by cultured luteal cells in the presence or absence of hCG. AA-LIP significantly reduced basal 6-keto-PGF1 alpha secretion in cultured luteal cells on day 2. Although the stimulatory effect of AA on luteal PGE2 production was maintained throughout the entire culture period, the lipoxygenase products of AA did not affect AA-stimulated PGE2 production by cultured luteal cell. These results suggest that the products of the lipoxygenase pathway may be important in the involution of human corpora lutea.