BRAIN LYS-AMINOPEPTIDASE ACTIVITY - CHANGES DURING CYCLE AND PREGNANCY

Lys-aminopeptidase activity levels during the estrous cycle (estrous a nd proestrous, in the morning and afternoon) and the pregnancy (2nd, 7 th, 14th and 20th day postinsemination and the parturition day), in se veral areas of the rat brain, were studied in this research. The selec ted brain regions were the frontal, parietal and occipital cortices, o lphactory bulbus, thalamus, hypothalamus, hippocampus, amygdala, stria tum and pituitary gland. The most significant changes were shown in th e hypothalamus and the pituitary gland. Thus, in these areas, the high er cyclic enzyme levels were found in the proestrous stage. During pre gnancy, there was a rise on the 7th and 14th days, with a decrease on the 20th day. Also, similar changes in the occipital cortex, striatum, hippocampus and amygdala were appreciated, but fewer than those obser ved in the hypothalamus and the pituitary. In conclusion, the activity of the aminopeptidase under study fluctuates during the estrous cycle and during pregnancy, as well as in the hypothalamic-pituitary axis a nd also in several extrahypothalamic areas of the rat brain.