Hormonal Control of Collateral Circulation

Abstract

The possible regulatory effects of growth hormone and of cortisone on the development of pulmonary collateral vessels after ligation of one pulmonary artery were investigated in the rat. The weights of the animals were regulated so that they did not differ significantly in the control and experimental groups at the end of the experiment. The extent of the collateral circulation was judged by visual inspection and by weighing the casts. Animals injected with cortisone acetate intramuscularly in doses of 5 mg daily for two weeks and then maintained on an average dose of 15 mg weekly, had less development of collateral circulation at four and eight weeks than did controls. Animals injected with growth hormone in doses of 0.1 mg daily, had significantly larger collaterals than did controls at eight but not at four weeks, as determined by the visual ranking method. These results indicate 1) that there can be chemical control of collateral circulation, and 2) that cortisone and growth hormone can influence the development of collateral vessels in part by mechanisms other than an effect on body weight.