The lipoxygenase pathways are involved in LH-stimulated progesterone production in bovine corpus luteum.
We have examined the effects of endogenous lipoxygenase products on basal progesterone (P4) production by cultured bovine mid-luteal cells. The involvement of lipoxygenase products in the stimulatory effect of LH on luteal cAMP accumulation and P4 production was also examined. Bovine luteal cells from mid-cycle corpora lutea (CL) were exposed for 16 h to a lipoxygenase inhibitor (nordihydroguaiaretic acid: NDGA; 0.33-33 microM). For the last 4 h of incubation, the cells were exposed to LH and/or three different lipoxygenase products, 5-, 12- and 15-hydroxyeicosatetraenoic acid (HETE). NDGA inhibited P4 production by the cells in a dose-dependent manner (P < 0.05). NDGA-reduced P4 production was reversed by the addition of 12-HETE, but not 5- or 15-HETE, whereas 5-, 12- and 15-HETE alone showed no significant effect on P4 production in the intact cells. Furthermore, NDGA (33 microM) blocked the stimulatory action of LH on P4 production (P < 0.05), without changing cAMP accumulation (P > 0.1). When the cells were exposed to 5-, 12- or 15-HETE with LH and NDGA, only 15-HETE maintained the stimulatory effect of LH on P4 production in the cells (P < 0.05). These results suggest that endogenous lipoxygenase products play important roles in P4 production by bovine CL, i.e. basal P4 production is supported by 12-HETE, and LH-stimulated P4 production is partially mediated via the activation of lipoxygenase and subsequent 15-HETE formation downstream of the LH-activated cAMP-PKA-phosphorylation pathway.
Taniguchi
Hiroaki
H
Department of Animal Science, Faculty of Agriculture, Okayama University, Japan.
Uenoyama
Yoshihisa
Y
Miyamoto
Yoko
Y
Okuda
Kiyoshi
K
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology; D008084:Lipoxygenase / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism / Q000494:pharmacology*; D009637:Masoprocol / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism*; D013997:Time Factors
D006893:Hydroxyeicosatetraenoic Acids; D016859:Lipoxygenase Inhibitors; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; D011374:Progesterone; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D009637:Masoprocol; D007986:Luteinizing Hormone; D008084:Lipoxygenase