Oestradiol and testosterone propionate as mitotic inhibitors during embryogenesis

« Influenza Degli Ormoni Sessuali Sulla Crescita Dell'Adenocarcinoma Mammario Spontaneo Del Topo in Vitro »

Explants from spontaneous mammary adenocarcinoma of C 3 H and IV B mice were treated « in vitro » with oestrone, progesterone and testosterone. The « roller-tubes » technique was used for the observation of the migration area, the « roller-slides » technique for histological preparations and mitotic index calculations, the Carrel flasks for phase contrast microscopical observations. Growth determination was carried out in 15 days old cultures by planimetric measurements of the migration area and calculations of the mitotic index.

1) Cultured tumor cells show a tendency to convert from round into fusiform shape, increasing considerably in size and assuming a more differentiated aspect (Caspersson's « B » cells). The tendency to cytological differentiation is accompanied with a gradual reduction of the proliferation.

2) Oestrone administration enhances considerably the growth (increase of the migration area to more than the 400 per cent) and the tendency to the cyto-histological differentiation of the tumor. The stimulating effect of oestone is exerted only on epithelial elements.

3) Progesterone administration brings about a lower increase of the growth (augment of the migration area of the 308 per cent at a dilution of gr. 1.100-5/cc. and of the 39 per cent at a dilution of gr. 5.10-5/cc.) and of the tendency to cyto-histological differentiation of the tumour. In contrast with what observed for oestrone, the stimulating effect would be manifest also on the stroma.

4) Testosterone administration inhibits strongly the tumour growth of the 66 per cent at a dilution of gr. 1.10-5/cc and of the 29 per cent at a dilution of gr. 5.10-5/cc.) without influencing its differentiation. The stroma seems to be scarcely influenced by hormonal treatment. The inhibiting action of testosterone is accompanied by regressive phenomena of the tumour elements.

Results show that the spontaneous adenocarcinoma of mouse maintains « in vitro » the hormono-dependency properties which are characteristic of the normal mammary cell.