Effect of ovarian steroids on uptake of radioactive amino acids by brain tissues

Effects of two major ovarian hormones, estrogen (E) and progesterone (P), on the uptake of amino acids by the brain nuclei of ovariectomized mice were examined. They were divided into four groups: (1) oil controls, (2) P-treated, (3) estradiol benzoate (E2B)-treated, and (4) E2B-primed P-treated mice. Two hr after the last hormonal treatment they were given a single s.c. injection of a mixture of 3H-leucine and 3H-methionine, and then sacrificed 2 hr later. Intensity of the uptake of radioactivity was measured on autoradiograms of the stained tissue sections. Group 1 showed a relatively high uptake of radioactivity by the SO, PV and SPH, compared with that by the remaining brain cells. Group 2 had a slight enhancement of the uptake by the VM, SPH and CC, compared with that in group 1. Group 3 showed a significant enhancement of the uptake by most of the preoptico-hypothalamic nuclei except for the VM, DM and PM, compared with that in group 1. Group 4 had slightly enhanced uptake by the POM, POL, SCH, SO, PV, VM, ARC, SPH and CC, compared with that in group 1. E-priming affected the uptake; it enhanced the uptake by the VM and SPH, and inhibited it by the PVA, AH, LH and CC. Uptake by the PM and EC remained unchanged in all groups. The present results suggest that two major steroids, E and P, influence protein synthesis in most of the brain regions including the preoptic and hypothalamic areas.(ABSTRACT TRUNCATED AT 250 WORDS)