EFFECT OF VARIOUS ABLATIONS IN THE HYPOTHALAMUS ON ESTABLISHED PREGNANCY IN THE RAT

Abstract

To investigate the role of the hypothalamus in the maintenance of established pregnancy, bilateral electrolytic lesions were made in various regions of the hypothalamus in Wistar rats on day 10 of gestation. These lesioned rats were compared with pair-fed controls, and controls fed ad libitum. No significant differences were noted between lesioned and pair-fed control rats in litter and fetal weights, length of gestation, or stillbirth rates. Lesioned rats were able to complete their pregnancies to term. Fetal birth weight was normal or slightly subnormal in the face of significant decreases, and in one group an increase, in maternal food intake. After lesions in some regions of the hypothalamus, there were changes in maternal endocrine weights, suggesting a disturbance of hypothalamic control of the anterior pituitary. These results show that pregnancy can be maintained successfully in the presence of large symmetrical lesions in several regions of the hypothalamus and support the concept that the fetus is nourished at the expense of maternal resources.