Figure 5.

Effects of insulin on the reproduction of model silkworm by regulating blood sugar

(A) Trehalose level in hemolymph (n = 3).

(A′) Egg number after trehalose injection in WT. Trehalose (0.5, 1.0, or 5.0 mg per pupa) was injected into WT in the P1 stage, and the number of eggs produced and laid was counted at the adult stage. Hemolymph samples were collected at 0, 0.5, 1.0, 1.5, and 144 h after 1.0 mg trehalose injection per pupa.

(B) Total AKT and phosphorylated AKT protein levels in the fat body. The gray values were calculated using ImageJ and the blue data represent the gray value ratio of P-AKT/β-actin and AKT/β-actin. The protein of AKT and P-AKT is 60 kD, and the protein of β-actin is 42 kD.

(C) Egg number of WT injected with LY294002. LY294002 (LY), a PI3K/Akt signaling pathway inhibitor, was injected into body fluids at a dose of 0.001 nmol per pupa in P1, and the number of eggs produced and laid was counted at the adult stage.

(D and E) Trehalose level in hemolymph (D and E) and Egg number (D′ and E′) after bovine insulin supplementation respectively in TBH and WT silkworm. Bovine insulin was injected into the body fluid in P1 at a dose of 100 μg per pupa. The hemolymph samples (n = 3) were collected at 0, 30, 60, and 90 min after injection to investigate the trehalose content and further count the number of eggs made and laid at the adult stage. The control (CK) was injected with the same volume of saline solution.

NC, negative control. Except for (B), the data in the figures were the mean ± SD. The data in (A, D, and E) were analyzed by the Student’s t test and the significance of the difference was ∗, p < 0.05; ∗∗, p < 0.01; ∗∗∗, p < 0.001. The data in (A′, C, D′, and E′) were analyzed by ANOVA, and the different letter among groups presents a significant difference.