A single dose of an androgen or oestrogen at birth affects the development and functioning of the reproductive system of rats and mice (for review, see Harris, 1964). The present study shows that hamsters react in a similar way.
Complete litters of hamsters were injected s.c. on the 2nd day after birth with either 300 μg. testosterone propionate (TP) or 150 μg. oestradiol benzoate (OB) in 0·05 ml. arachis oil. Litters of controls received the vehicle only.
No abnormalities of the external genitalia were observed in animals of either sex. There were no vaginal manifestations of the oestrous cycle (Orsini, 1961) in any of the hormone-treated animals; vaginal smears showed persistent cornification.
After being subjected to a number of behavioural tests (Swanson, 1966a, b) the animals were killed, their reproductive organs and adrenals weighed (Table 1) and processed by routine methods for histological study.
No significant sex differences in