Endocrinology Vol. 140, No. 2 1026-1029
Copyright © 1999 by The Endocrine Society
Heparin-Binding Property of Human Prolactin: A Novel Aspect of Prolactin Biology
Sudha Khurana,
Robin Kuns and
Nira Ben-Jonathan
Department of Cell Biology, University of Cincinnati Medical
School, Cincinnati, Ohio 45267
Address all correspondence and requests for reprints to: Nira Ben-Jonathan, Ph.D., University of Cincinnati, Department of Anatomy and Cell Biology, 231 Bethesda Avenue (ML 521), Cincinnati, Ohio 45267.
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Abstract
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Prolactin (PRL) shares several characteristics with growth
factors and cytokines, many of which are known to bind to heparan
sulfate proteoglycans. In this study we examined the heparin-binding
properties of selected members of the PRL/GH family, using heparin
affinity columns followed by gel electrophoresis/Western blotting.
Purified human PRL and its cleaved 16K fragment, but not human GH or
placental lactogen, were retained on the heparin column and were
displaced by 0.5 M NaCl. Native PRL in human pituitary extracts and
amniotic fluid showed a similar binding affinity to heparin as the
purified hormone. None of the other hormones tested, e.g., rat, ovine
and bovine PRL, glycosylated ovine PRL or rat GH, bound to heparin. Two
consensus heparin-binding sequences are present in human PRL but not in
the other hormones included in this study. We postulate that the
heparin-binding capability of PRL affects its biological activity as a
growth factor and the angiostatic actions of its 16K fragment.
Received October 6, 1998.