Which one of the following statements concerning protein hormones is correct?

Question

Quizplus · Accepted Answer

Protein hormones usually bind to cell surface receptors and activate signal transduction pathways inside the target cell. One common pathway involves activation of adenylyl cyclase, which leads to the production of cyclic AMP (cAMP) and subsequent activation of protein kinase A (PKA). PKA can then phosphorylate various cellular enzymes, leading to changes in cell metabolism and gene expression. This is a general mechanism for many protein hormones, including epinephrine, glucagon, and follicle-stimulating hormone (FSH). Option A is incorrect because protein hormones usually do not enter the cell or nucleus, but instead act through membrane-bound receptors. Option C is also incorrect, as protein hormones usually have a stimulatory effect on gene expression rather than suppressive. Option D is partially correct in that some protein hormones may bind to transport proteins like albumin in the circulation, but not all protein hormones require this mechanism for transport.

Which One of the Following Statements Concerning Protein Hormones Is