The effect of temperature on steroid biosynthesis by testes of the dogfish, Scyliorhinus caniculus.

1. Testes of the dogfish, Scyliorhinus caniculus, were incubated with [3H]pregnenolone and [3H]testosterone at a range of temperatures from 1 to 36 degrees C. 2. Yields of testosterone from pregnenolone were maximal between 11 and 16 degrees C, corresponding to the breeding temperature of the species. 3. Yields of glucuronides and sulphates increased from 1 to 26 degrees C. 4. Yields of an unidentified polar metabolite increased with temperature and it is suggested that this may play a regulatory role in elasmobranch reproduction.