Segmental distribution and gestational changes of GABA-transaminase activity in the rat oviduct.
The occurrence and the localization of 4-aminobutyrate:2-oxoglutarate transaminase (GABA-transaminase) in the non-pregnant and pregnant rat oviduct were examined using biochemical and enzyme histochemical techniques. Specific GABA-transaminase activity was detected in the ampullary and isthmic portions of the oviduct as well as in the utero-tubal junction. The enzymic activity was lower in the ampullary than in the isthmic or intramural segments of the oviduct. Pregnancy induced a significant increase of GABA-transaminase activity in each portion of the oviduct. Enzyme histochemistry showed the highest GABA-transaminase reactivity at the level of the epithelial cells of the oviduct irrespective of the portion of the tube examined. A faint specific activity was demonstrated in the smooth muscle of the oviduct while the serosa did not show specific staining. Our findings indicate that: the observed increase of GABA-transaminase activity in the oviduct of the pregnant rat may be responsible for the reduced GABA levels in the oviduct during gestation; and the extraneuronal localization of GABA-transaminase activity does not seem to support the suggestion of a possible GABAergic innervation of the oviduct.
D000612:4-Aminobutyrate Transaminase / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D005187:Fallopian Tubes / Q000032:analysis / Q000201:enzymology*; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D000612:4-Aminobutyrate Transaminase