It is known that topical all-trans-retinoic acid (RA) modulates growth and
differentiation of skin and its cutaneous appendages. To examine whether a
pre-natal exposure to a potentially non-teratogenic dosage of all-trans-PA
had any effect on vibrissal follicle development, the histologic and immuno
histochemical responses to RA during its morphogenesis in NMRI mouse were i
nvestigated. After a single oral dose of 30 mg/kg body weight of all-trans-
RA on day 11.5 of gestation, no fetal malformations were detected and the h
istological features and the distribution of keratin (K) proteins in compar
able stages of vibrissal development were similar for the untreated, vehicl
e-treated and RA-treated mice. The absence of teratogenic response and of a
dverse effects on the vibrissae under the experimental conditions indicates
that this protocol may be useful for investigation of the effects of pre-n
atal exposure to RA on the post-natal development of experimental tumours i
n the mouse skin.