| Abstract: | Hair follicles are initiated in mice homozygous for Strong's luxoid gene at the normal times. The dermis from 16 days of gestation to nine days after birth lags in development. The adipose layer instead of enlarging at the normal time of three days after birth delays until nine days. The growth of the first cycle hairs is inhibited, particularly on dorsal surfaces. Some follicles of all types degenerate. The surviving follicles enter telogen at seven days after birth, after forming only short unpigmented or poorly-pigmented hairs. Many follicles immediately begin a second cycle of growth, in which more normal hairs develop and a substantial adipose layer forms. No alopecia develops on ventral surfaces, but growth of the first cycle ceases and the second cycle commences earlier than normal; the hairs formed are abnormal. Abnormal hair growth in Strong's luxoid homozygotes may be a result of the retarded growth of the dermis or both defects may be secondary to a more fundamental defect. |
