Hormonal Influence on the Adrenergic Receptors of the Ureter 1

SUMMARY A series of isometric studies were performed on rat ureters to investigate the effect of pre‐treatment with œstrogen and progesterone on the α‐and β‐adrenergic responses. The results indicate a facilitation or enrichment of the α‐adrenergic response by œstrogen, and a similar effect on the β‐response by progesterone. It is suggested that the hormonal component of the ureteric dilatation of pregnancy is the result of the effect of progesterone on the β‐adrenergic receptors.