The influences of leukotriene C4 on the metabolism of labelled glucose in uteri isolated from ovariectomized and from ovariectomized-estrogenized rats. Effects of indomethacin.

The effects of leukotriene C4 (LTC4), nordihydroguaiaretic acid (NDGA) and FPL-55712, on the metabolism of labelled glucose (U14C-glucose) in uteri isolated from spayed rats and from spayed-estrogenized rats, incubated in the presence and in the absence of indomethacin, were explored. Indomethacin (10(-6)M), enhanced significantly 14CO2 formation from labelled glucose, both in uteri from ovariectomized rats and in uteri from ovariectomized-estrogenized animals. In uteri from spayed not-estrogenized rats, expose 'in vitro' to indomethacin, NDGA (10(-5)M), an inhibitor of the 5-lipoxygenase, as well as FPL-55712 (10(-5)M), a LT antagonist, reduced significantly the enhanced metabolism of glucose evoked by indomethacin, an inhibitor of the cyclo- oxygenase. On the other hand, LTC4 (10(-7)M), augmented the metabolism of labelled glucose, reaching values even greater than those induced by indomethacin. In the spayed-estrogenized group LTC4 (10(-10)-10(-7)M) enhanced the formation of labelled CO2 from labelled glucose as much as indomethacin (10(-6)M) did, whereas neither NDGA nor FPL-55712 were effective. In addition, in uteri from ovariectomized-estrogenized rats, incubated with indomethacin, NDGA and FPL-55712, decreased the augmenting action of indomethacin on glucose metabolism, whereas LTC4 (10(-10)-10(-7)M) evoked a complete reversal of the inhibitory influence of NDGA on the formation of 14CO2. The force-going results suggest that tissue 5-lipoxygenase products, particularly LTC4, are involved in the metabolism of labelled glucose by rat uteri, mainly when the cyclo-oxygenase pathway is inhibited by indomethacin and the tissue is deprived of estradiol.(ABSTRACT TRUNCATED AT 250 WORDS)