Early histological studies support these data. In a detailed study of the histology of the interstitial gland, Deanesly indicates that the interstitial cells of the anestrous ovotestis are large and glandular and that they contain lipoids, while those from pregnant females are regressing and vacuolated. Also noteworthy in this regard is the similarity of plasma testosterone levels in autumn females and males, despite an order of magnitude higher concentration and content of gonadal testosterone in males (Table 1). proventil inhaler
Perhaps the most striking aspect of the ovotestis is the cyclical nature of steroidogenic activity between the ovarian and interstitial gland components. This suggests that steroidogeneses in the ovary and interstitial gland are under independent control—a situationatoddswithourcurrent understanding of the regulation of gonadal steroidogenesis. Ordinarily, gonadotropins signal to the steroidogenic cells of the gonad to increase the synthesis of a particular steroid. In T. europaea, the interstitial gland is up-regulated in its production of testosterone while the ovarian portion is in its least active phase of steroidogenesis.