Arginine vasotocin binding component in the uterus (shell gland) of the chicken

The plasma membrane fraction of the uterus of the chicken was found to contain a component that shows specific binding to arginine vasotocin (AVT), arginine vasopressin (AVP) and oxytocin (OT). This binding component possesses a higher affinity to AVT than to AVP or OT, and the affinity to AVT was higher in laying hens than in non-laying hens and immature pullets, while the maximum number of binding sites per mg protein was less in the laying hens. Intramuscular injections of either estradiol-17 beta, progesterone or testosterone into the immature pullets for six consecutive days caused an increase in the affinity and number of binding sites. The results suggest that AVT receptors are present in the chicken uterus and that their binding properties are affected by ovarian steroid hormones.