Abstract
Effects of septal or preoptic lesions on the development of ovarian compensatory hypertropohy (OCH) were investigated. Radiofrequency lesions were made in the medial septum (MSL), lateral septum (LSL), dorsal septum (DSL) or dorsal preoptic area (DPOAL) in female rats. At the time of brain surgery, the left ovary was removed and weight. Two weeks after surgery, the wet weight of the remaining ovary was recorded in each rat. The OCH% in DPOAL females was significantry lower than that in the hemicastrated controls. On the other hand, MSL facilitated the development of OCH, the mean OCH% being significantly higher than that of controls. The OCH% in the LSL and DSL groups was comparable to that in controls. These results suggest that the medial septum plays an inhibitory role and, conversely, that the dorsal preoptic area plays a facilitory role in regurating ovarian compensatory hypertrophy.
The brains in a number of animals with or without brain surgery were subjected to LH-RH immunohistochemical examinations to clarify the effects of the lesions on LH-RH neurons which send fibers to the median eminence. LH-RH immunoreactive terminals in the median eminence were not significantly different among the groups examined, indicating that the elevation or reduction of OCH% in MSL or DPOAL rats may not be the result of direct damage to LH-RH neurons in the septal area and POA. Rather, the lesions were thought to affect the neural substrate controlling the activity of LH-RH neurons during the development of OCH.
