Wieczorek Z

S13.9 A proline-rich polypeptide (PRP) and its active nonapeptide (NP) fragment affect the expression of a receptor for peanut agglutinin (PNA) on murine thymocytes

Inhibition was dose dependent between 10 -7 and 10 -4 M dex. The dex effect disappeared after 6d of continuous exposure. In addition, total amounts of intracellular 3H-label, HMG, and mucin were reduced after 4 h of dex treatment. However, dex did not alter the stimulatory effect of methacholine on the secretory rate for total H M G and mucin. We suggest that dex may decrease glycoconjugate secretion by inhibiting glucosamine uptake and consequently the biosynthesis and release of glycoconjugates. Failure of dex to inhibit glycoconjugate secretion after 6d suggests that if similar effects occur in vivo, they may be transient. The mechanism by which inhibition is overcome requires further study. (Supported by NIH grants HL19171 and HL42384). 1. Marom et al.: Am. Rev. Respir. Dis., 1984, 129:62-65. 2. Leigh, M. W., Cheng, P. W., Boat, T. F. Biochem., 1989, 28:9440