Abstract
The fluctuations of trehalose content and trehalase activity accompanying the growth of middle and posterior silkglands of the silkworm, which was controlled by 1-substituted-5-[(E)-2, 6, dimethyl-1, 5-heptadienyl] imidazole (KK-42), was examined. A topical application of KK-42 (50 μg/larva, once a day) to the fifth instar larvae from 3rd through 5th day delayed the spinning for 3 days, although non-treated larvae spun the cocoon silk on day 6. At the spinning, the middle glands of the KK-42-treated larvae were about 1.5 times heavier than those of non-treated larvae. The fluctuation of trehalose content in both middle and posterior silkglands accompanying the growth of silkglands was different between the non-treated and the KK-42 treated larvae. The administration of KK-42 delayed the onset of the activity for 3 days. Trehalase activity in the middle and posterior glands occurred immediately after the spinning, but in the middle silkglands it was about 13 times higher than in the posterior glands of non-treated larvae. Thus, there appears to be a difference in trehalose metabolism between the middle and the posterior silkglands, and, moreover, the prolongation of the silkgland growth by KK-42 may affect their trehalose metabolism.
