AJP - Endocrinology and Metabolism, Vol 257, Issue 6 E804-E808, Copyright © 1989 by American Physiological Society
Synthesis and characterization of fluorescein- and rhodamine-labeled probes for vasotocin receptors
A. Buku, S. Masur and P. Eggena
Department of Physiology and Biophysics, Mount Sinai Medical School, City University of New York, New York 10029.
Fluorescent analogues of vasotocin, [1-(beta-mercaptopropionic acid),
9-(p-aminofluoresceinylphenylalanine)]arginine vasotocin [[MPA1,
(p-NH2flu)Phe9]AVT] and [1-(beta'-mercaptopropionic acid), 9-(p-amino
rhodaminylphenylalanine)]AVT [[MPA1, (p-NH2rhod)-Phe9]AVT], were
synthesized by the solid-phase method. These compounds yielded half-maximal
hydrosmotic responses (half-maximal values) in the toad urinary bladder at
2 X 10(-9) M. Epifluorescence microscopy showed punctate basal localization
of analogues on the majority of bladder epithelial cells within 20 min. The
cellular localization was prevented by vasotocin. These fluorescent
analogues may serve as useful probes for vasotocin receptors in toad
bladder and in tissues from other species that use vasotocin as their
antidiuretic-pressor hormone.
