Activity of catechol-o-methyltransferase in brain regions and adrenal gland during the oestrus cycle.

The activity of the enzyme catechol-O-methyltransferase (COMT) during four different phases of the oestrus cycle were determined. Brain and hypothalamus had highest level of COMT activity during oestrus phase, while at pro-oestrus it was at its lowest level. COMT activity in the adrenal gland was also modified during the four phases with the maximum level at met-oestrus and minimum at pro-oestrus phase. The results provide evidence to show that COMT in the brain, hypothalamus and the adrenals is markedly affected by changes in physiological status of the female rats and its evolution in brain is different from adrenal gland during the oestrus cycle. The variations in the activity of COMT may be the consequence of modified endocrine activity which takes place naturally during oestrus cycle.