AJP - Cell Physiology, Vol 265, Issue 6 C1653-C1657, Copyright © 1993 by American Physiological Society
Histamine H2 receptor mediates keratan sulfate secretion in rabbit chondrocytes: role of cAMP
K. Fukuda, F. Matsumura and S. Tanaka
Department of Orthopaedic Surgery, Kinki University School of Medicine, Osaka, Japan.
We obtained evidence for the presence of a single class of histamine H2
receptor on rabbit chondrocytes. Stimulation of these receptors with
specific H2 agonists led to an inhibition of keratan sulfate secretion and
rapid (15 min) accumulation of intracellular adenosine 3',5'-cyclic
monophosphate (cAMP). Factors such as prostaglandin E2 and parathyroid
hormone, which stimulate short-term increases in cAMP, also caused a
reduction in keratan sulfate secretion. Conversely, cholera toxin and
forskolin, which enhance cAMP accumulation over 48 and 4 h, respectively,
as well as a continuous exposure to dibutyryl cAMP, stimulated keratan
sulfate secretion. These data suggest that intracellular cAMP must be kept
above a certain level for a prolonged period to stimulate keratan sulfate
secretion. We conclude that inhibition of keratan sulfate secretion is
coupled with activation of the H2 histamine receptor.
