Cell surface localization of a novel non-genomic progesterone receptor on the head of human sperm.
Cell surface receptors for progesterone were visualized in human sperm using fluorescein isothiocyanate-progesterone 3-(O-carboxymethyl) oxime-bovine serum albumin (FITC prog CMO BSA). The receptors were confined to the head and not the midpiece or tail. FITC prog CMO BSA was also an effective stimulus to elevate intracellular free calcium in human sperm as detected by fura-2 fluorescence. The elevation of intracellular free calcium is a stimulus for the acrosome reaction, a process which is necessary to occur for sperm to fertilize the egg. It is proposed that progesterone, which is present in the female reproductive tract, can bind to progesterone receptors located in the plasma membrane of the sperm head and elicit an influx of Ca2+ into the underlying cytoplasm and or acrosome and induce the acrosome reaction and facilitate fertilization.
Blackmore
P F
PF
Department of Pharmacology, Eastern Virginia Medical School, Norfolk 23501.
Lattanzio
F A
FA
D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D008297:Male; D011374:Progesterone / Q000494:pharmacology; D011980:Receptors, Progesterone / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013077:Sperm Head / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D013081:Sperm Motility
D011980:Receptors, Progesterone; D011374:Progesterone; D016650:Fluorescein-5-isothiocyanate; D002118:Calcium