(A. TOXICANT-INDUCED CELLULAR DYSREGULATION) 3) Dysregulation of Extracellular Signal Production 1 __ exert MITOGENIC EFFECTS ON ENDOCRINE GLANDS in the periphery by acting on cell surface receptors. 2 UNDER NEGATIVE FEEDBACK CONTROL by PERIPHERAL GLAND HORMONES. 3 __ secretion of pituitary hormone produces apoptosis followed by involution of the peripheral target gland