Effect of lysine vasopressin dimers on blood pressure and some endocrine functions

¹ Endocrine and Polypeptide Laboratories, Veterans Administration Hospital, and Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana

Some biological properties of lysine vasopressin dimers, derived by polymerization from natural lysine vasopressin or made synthetically, were studied and compared to those of natural lysine and arginine vasopressin or USP posterior pituitary standard. "Natural" and synthetic dimers caused patterns of blood pressure responses different from those obtained with vasopressin. In the urethane-Dibenzyline-treated rat, the rise in blood pressure obtained with dimers developed more slowly and lasted much longer than that given by vasopressin or angiotensin II. The dimers also caused long-lasting blood pressure responses in the anesthetized dog. In the anesthetized chicken the dimers caused a prolonged fall in blood pressure clearly different from the effect of vasopressin. The antidiuretic responses to the dimers in the rat was of slightly shorter duration than that to USP posterior pituitary standard. The dimers also had significant corticotrophin-releasing factor (CRF) activity at the level of 30 mU pressor activity, as evidenced by the release of ACTH in the rat treated with morphine and Nembutal. Both "natural" and synthetic dimer caused depletion of ovarian ascorbic acid in the rat pretreated with gonadotrophin. "Natural" but not synthetic dimer increased the release of I¹³¹ from the mouse thyroid.

Key Words: blood pressure in the rat • blood pressure in the dog • blood pressure in the chicken • ovarian ascorbic acid (rat) • release of I¹³¹ from thyroid (mouse) • ACTH-releasing (CRF) activity

Submitted on December 6, 1963