The role of lipoxygenase products on the endocytosis of yolk proteins in insects: Participation of cAMP

摘要

The participation of eicosanoids and second messengers in the regulation of endocytosis by the ovaries was investigated using the uptake of Rhodnius heme binding protein (RHBP) as an experimental model. The rate of RHBP uptake decreased up to 40% in the presence of BWA4C and NDGA, 5 and 12-lipoxygenase inhibitors, respectively, suggesting the involvement of lipoxygenase products in endocytosis regulation. Addition of Leukotriene 134 (LTB4; one product of the 5 lipoxygenase pathway) increased in vitro the uptake of RHBP by 30%. The content of (AMP) in the Rhodnius ovaries were monitored after treatment with different eicosanoids and inhibitors of eicosanoids synthesis. The amount of cAMP decreased in the presence of indomethacin (by 50%), while treatment with PGE(2) induced an increase of 85% of this messenger in the ovaries. The presence of LTB4 in the medium inhibited in 60% the content of cAMP in the ovaries, while BWA4C induced a 100% increase of this messenger in the ovaries. Addition of 1 muM DBcAMP in the medium resulted in a 30% decrease in the rate of RHBP uptake. Taken together, these data show that hydooxygenose and lipoxygenase products participate in the control of protein internalization by modulation of cAMP levels