Possible Alteration of Female Specific Protein by Estradiol-17β in Silkworm,Bombyx mori L

In our attempt to understand the biological significance of natural occurrence of estradiol-17β (E₂, a vertebrate female sex steroid) in silkworms effect of exogenous estradiol-17β injection on the appearance of female-specific proteins both in pupal hemolymph and ovarian extracts was undertaken. A single injection of 2 μg of E₂ per g of body weight on the 3rd day in the 5th instar female silkworm (Bombyx mori L. race Nistari) larvae revealed more accumulation of both 170- and 43 kDa proteins from the day 3 to 7 of pupal life with a peak on the day 7 in comparison to the untreated (control) hemolymph. On the contrary, the ovarian extracts revealed highest accumulation of both the proteins in female silkworm pupae on the day 4 and thereafter, declined gradually to level up with the control on the day 8. The fertilized egg extracts irrespective of control and E₂-treated silkworms failed to establish quantitative differences of the proteins in question. Thus the metabolic role of E₂ on the female-specific proteins in silkworm could not be ruled out.