COMPARISON OF CORTICAL THICKNESS IN MALE AND FEMALE RATS - NORMAL AND GONADECTOMIZED, YOUNG AND ADULT

Removal of rat ovaries at Day 1 increases cortical thickness by Day 90 when compared with intact littermates (C. Pappas, 1977, Ph.D. Thesis, University of California, Berkeley, Calif.). In the present experiments, using Day 1 sets of sextuplets, one male and one female were gonadectomized; one male and one female were sham-operated; one male and one female were left intact to serve as normal controls. After weaning at Day 21, the animals were separated three to a cage (20×20×32 cm) according to sex and condition. At 90 days of age all were ether-anesthetized and sacrificed. From Formalin-perfused and fixed frozen brains, transverse sections were cut from motor, somesthetic, and occipital regions. Projected, thionin-stained sections were outlined and the cortex was measured. Significant differences in cortical thickness were seen between ovariectomized rats compared with sham-operated littermates. There were no significant cortical thickness differences between normal intact males and females; or between rats ovariectomized at Day 90 and Day 300 compared 90 days later with sham-operated littermates. © 1979 Academic Press, Inc.