Abstract
ABSTRACT An attempt was made to evaluate the growth hormone (GH)-releasing activity in extracts of the stalk-median eminence region (SME) from kittens with bilateral lesions of the paraventricular nuclei, which showed a marked growth retardation, and from sham-operated animals. SME extract from the sham-operated control kittens induced a significant decrease in pituitary GH content. However, SME extract from kittens with bilateral lesions in the region of the paraventricular nuclei failed to induce the depletion of pituitary GH content. The cerebral cortical extracts from both groups elicited no effect on pituitary GH. These results show that the hypothalamus of the lesioned kittens has no GH-releasing activity, i. e. GH-releasing factor (GRF) is lacking. This suggests that, in kittens, the area of the paraventricular nuclei plays an important role in the synthesis of GRF, so that destruction of this area causes growth impairment.
