Growth hormone and insulin are protein hormones that regulate carbohydrate metabolism by hepatocytes (liver cells) through the activation of intracellular signaling pathways. Researchers investigated whether the two hormones trigger the same or different intracellular signaling pathways in hepatocytes. The researchers added either growth hormone or insulin to parallel cultures of hepatocytes. At several time points after the hormone addition, they purified total intracellular protein from the cells and quantified the level of the phosphorylated forms of two proteins involved in two different signaling pathways (Figure 1, A and B)
(d) The researchers claim that the similar regulation of carbohydrate metabolism
by hepatocytes when the cells are treated with growth hormone or insulin results from the activation of different signaling pathways. Use the data from the researchers’ experiment to support their claim.
