 In female rats, there is a greater expression of estrogen receptor beta in the periventricular nuclear cells, which is thought to lead to different levels of LH secretion in males and females.This region has been shown to aid in the production of somatostatin and research shows that neurons releasing somatostatin are stimulated to do so by glutamatergic innervation and then this allows them to stimulate the release of growth hormone.There is thought to be a differential level of secretion of somatostatin between males and females by the periventricular nucleus and that is thought to be responsible for the sexual dimorphism of growth hormone secretion.