Which of the following is the second-messenger molecule for the intracellular

A researcher investigating mechanisms of intracellular signaling develops a mouse model using recombinant DNA technology to generate a gene knockout. The F2 progeny exhibit dwarfism, hypogonadism, and hypothyroidism with low levels of follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone but normal levels of ACTH. In addition, the female progeny exhibit impaired milk secretion. Which of the following is the second-messenger molecule for the intracellular signaling system that is most likely impaired in this mouse model?

(A) cAMP
(B) cGMP
© Inositol trisphosphate
(D) Steroid nuclear hormone receptor
(E) Tyrosine kinase