GROWTH-REGULATORY PROPERTIES OF ATRIAL-NATRIURETIC-FACTOR

Recent evidence supports the notion that atrial natriuretic factor (ANF) has growth-regulatory properties. In the adrenal gland, ANF inhibits growth specifically in the zona glomerulosa. In the kidney, ANF causes an antimitogenic, antiproliferative effect in cultured glomerular mesangial cells. In vascular smooth muscle, ANF inhibits cell proliferation (hyperplasia) as well as cell growth (hypertrophy). ANF has growth-regulatory properties in a variety of other tissues such as brain, bone, myocytes, red blood cell precursors, and endothelial cells. The cellular mechanisms involved in the growth-regulatory actions of ANF are not totally clear. Evidence supports involvement of both biological and clearance receptors for ANF, guanosine 3',5'-cyclic monophosphate (cGMP) and cGMP-independent mechanisms, and protooncogene expression. For the most part, the actions reviewed in this report represent in vitro phenomena, and it is unclear whether these effects are relevant to normal physiology or pathophysiology. Nevertheless, an emerging hypothesis is developing which states that circulating and autocrine/paracrine factors such as ANF interact to regulate the vasomotor tone and cellular growth of a variety of tissues such as vascular smooth muscle and the glomerulus.