Interaction between ractopamine and growth hormone in the metabolism of hypophysectomized female rats

Abstract

Ractopamine and growth hormone have been extensively studied due to their ability to generate a better partition of nutrients in the body, providing an increased muscle protein synthesis and lipolysis in adipose tissue. Thus, this article aims to check the effects of interaction between these substances on the metabolism of hypophysectomized female rats, and their individual effects on the body composition of these animals. Thirty Fisher rats were distributed into five treatments, one of them was a normal control group, one was a hypophysectomized control group, and the other three were hypophysectomized animal groups treated with ractopamine (80 mg/kg/day), with growth hormone (4 mg/kg/day), and with a combination of them, all with six replicates in each group. The association between these substances provided a higher percentage of protein and decreased ether extract in the animals’ carcass. Furthermore, it caused an increase in water intake, in urine production, and decreased relative weight of kidneys, liver, and spleen when compared to the control group. The use of growth hormone provided a higher final weight gain and feeding effectiveness, lower heart weight and increased blood glucose level, and the use of ractopamine resulted in a higher lung weight, increased total cholesterol and IGF-1, and decreased peptide C concentration.

Keywords

• Growth hormone
• Ractopamine
• Female rats