Intraperitoneal injection of genistein affects the distribution and metabolism of cholesterol in female yellow catfish Tachysurus fulvidraco.

Genistein is an abundant phytoestrogen in soybean. This study aimed to determine the effects of genistein on cholesterol distribution and metabolism in female yellow catfish. Three hundred fish (49.2 ± 1.4 g) were randomly divided into five treatments and received intraperitoneal injections as follows: (1) blank, no injection; (2) control, vehicle only; (3) E2, 17β-estradiol at 10 μg·g-1 body weight; (4) low genistein doses, genistein at 10 μg·g-1 body weight; (5) high genistein doses, genistein at 100 μg·g-1 body weight. Both high and low genistein doses significantly reduced (p < 0.05) serum TC and LDL-C 24 h after injection. Moreover, the high genistein doses significantly reduced (p < 0.05) serum HDL-C. Both high and low doses of genistein significantly increased (p < 0.05) hepatic TC. Only high genistein doses significantly increased (p < 0.05) ovary TC. In the liver, both high and low genistein doses significantly increased (p < 0.05) protein and mRNA expression of ldlr. Meanwhile, high genistein doses significantly decreased (p < 0.05) mRNA expression of hmgcr. In ovary tissue, high genistein doses significantly decreased (p < 0.05) mRNA expression of cyp11a1. These results suggested that genistein affected the cholesterol distribution in female yellow catfish. Both high and low doses of genistein reduced cholesterol content in blood and increased its content in the liver by increasing the uptake of blood cholesterol. Meanwhile, high genistein doses may inhibit hepatic cholesterol synthesis. Additionally, high genistein doses could increase cholesterol transfer from serum into the ovary and disturb cholesterol conversion to pregnenolone.