Hormones and hormonal target cells in the testis.

Studies over the last few years have greatly increased our knowledge about target cells for sex hormones and gonadotropins in the testis. A diagram illustrating our present state of knowledge is given in Fig. 1.

Regional distribution of DMBA-induced mammary tumours in the rat.

Since human mammary cancers have a preference for certain regions of the breast, registration of the topography of DMBA-induced mammary tumours in rats was performed. This revealed that most of the tumours occurred in the upper, or thoracic, mammary glands. While the number of tumours in the two abdominal mammary regions was found to be rather constant, the incidence in the two thoracic regions had a tendency to mutual variations.

DMBA-induced mammary tumours in locally irradiated rats.

Local X-ray irradiation (400 r) covering 3 abdominal mammary glands revealed no tumours in the irradiated region after 10 months. A similar irradiation 1 or 10 days prior to i.v.