Gamma-aminobutyric acid, its related enzymes and receptor-binding sites in the human ovary and fallopian tube.

The concentration of gamma-aminobutyric acid (GABA), the activities of related enzymes, i.e. glutamate decarboxylase and GABA transaminase, as well as the level of specific GABA binding sites were determined in ovaries and fallopian tubes obtained surgically from 31 women. None of the biochemical parameters examined showed a correlation with the age and hormonal background (serum estradiol and progesterone levels) of the patients. The respective ovarian and tubal values did not differ significantly in groups operated on because of uterine myoma and carcinoma. In organs from pregnant women, however, most GABAergic markers altered significantly. These findings indicate some gestation-related role for the ovarian and tubal GABA systems in humans.