Effects of a circadian mutation on seasonality in Syrian hamsters (Mesocricetus auratus).

In Syrian hamsters, exposure to short photoperiods or constant darkness induces a decrease in gonadotrophin secretion and gonadal regression. After 10-12 weeks, animals undergo spontaneous gonadal reactivation, gonadotrophin concentrations rise, and in males, testes size increases and spermatogenesis resumes. The tau mutation shortens the period of… (More)