Differential Effects of Anterior and Middle Hypothalamic Lesions on Vaginal Opening and Cyclicity

Publisher Website
Google Scholar
Abstract
Lesions of different sizes were placed in the anterior hypo-thalamus or in the middle hypothalamus (level of arcuate nuclei) of 22-day-old female rats. Animals with anterior lesions showed a distinct parallelism between lesion size, advancement of vaginal opening (VO), and tendency towards prolonged and persistent oestrus. The largest lesions advanced VO by 13 days and caused persistent oestrus in nearly all rats. Lesions in the middle hypothalamus had no marked influence on cyclicity, but a dependence of VO on the size and localization of the lesion was clearly present. Small lesions destroying parts of the arcuate nuclei and large lesions destroying the arcuate nuclei nearly completely and extending into the area of the paraventricular nuclei caused an advancement of VO by 8 days or more. However, lesions of intermediate size, similar to those of the previous category but not reaching the paraventricular nuclei, advanced VO by 3-4 days only. The bearing of these findings on the control of sexual maturation is discussed.

This publication has 0 references indexed in Scilit: