Endocrinology, Vol 135, 1307-1315, Copyright © 1994 by Endocrine Society

ARTICLES

Synergistic effects of parathyroid hormone and 1,25-dihydroxyvitamin D3 on proliferation and vitamin D receptor expression of rat growth cartilage cells

G Klaus, B von Eichel, T May, U Hugel, H Mayer, E Ritz and O Mehls
Department of Pediatrics, University of Heidelberg, Germany.

We investigated possible interaction of 1,25-dihydroxyvitamin D3 [1,25- (OH)2D3] and PTH on: 1) proliferation (monolayer culture) and colony formation (agarose stabilized suspension cultures); 2) expression of 1,25-(OH)2D3 receptor (VDR); and 3) cAMP response to PTH, using primary cultures of chondrocytes from rat tibia proximal epiphysis. 1 alpha,25- (OH)2D3 stereospecifically stimulated DNA synthesis, cell counts, and colony formation at low concentration (10(-12) M). Within 6 h bovine PTH (bPTH)(1-34), human PTH (hPTH)(28-48) (10(-10) M), (Bu)2cAMP (1-2 mM), and 12-O-tetradecanoyl-13-acetate (10(-8) M) increased [3H]thymidine incorporation in the absence and presence of 1,25- (OH)2D3. Both PTH fragments also stimulated chondrocyte growth and colony formation in a Ca-dependent fashion. Prolonged exposure to bPTH(1-34) or hPTH(28-48) did not affect baseline DNA synthesis but increased the stimulatory effect of 1,25-(OH)2D3. This increase was inhibited in the presence of H7 (inhibition of PKC) or the monoclonal hPTH(1-38) antibody A1-70. In subconfluent chondrocyte cultures VDR was up-regulated by bPTH(1-34) and hPTH(28-48) (10(-10) M) or activators of protein kinase C (PKC), but not by (Bu)2cAMP. It was blocked by cycloheximide and actinomycin D and persisted in the presence of Ca- channel blockers. Inhibition of PKC by H7 also blocked the effect of bPTH(1-34) on VDR. The cAMP response to bPTH(1-34) was not affected by 1,25-(OH)2D3. We conclude that: 1) DNA synthesis, cell proliferation, and colony formation in chondrocyte monolayer or suspension cultures is increased by aminoterminal and midregional PTH fragments and by cAMP analogs in a Ca- dependent fashion; 2) bPTH(1-34) and hPTH(28-48) up- regulate VDR by cAMP-independent, PKC-dependent steps requiring transcriptional and translational processes; both PTH fragments also amplify the effect of 1,25-(OH)2D3 on DNA synthesis; and 3) no difference is found between the bPTH(1-34) and hPTH(28-48) fragments with respect to chondrocyte proliferation and VDR up-regulation, although the two differ with respect to stimulation of cAMP production.

This article has been cited by other articles:

				T. M. Murray, L. G. Rao, P. Divieti, and F. R. Bringhurst Parathyroid Hormone Secretion and Action: Evidence for Discrete Receptors for the Carboxyl-Terminal Region and Related Biological Actions of Carboxyl- Terminal Ligands Endocr. Rev., February 1, 2005; 26(1): 78 - 113. [Abstract] [Full Text] [PDF]

				Z. Schwartz, H. Ehland, V. L. Sylvia, D. Larsson, R. R. Hardin, V. Bingham, D. Lopez, D. D. Dean, and B. D. Boyan 1{alpha},25-Dihydroxyvitamin D3 and 24R,25-Dihydroxyvitamin D3 Modulate Growth Plate Chondrocyte Physiology via Protein Kinase C-Dependent Phosphorylation of Extracellular Signal-Regulated Kinase 1/2 Mitogen-Activated Protein Kinase Endocrinology, July 1, 2002; 143(7): 2775 - 2786. [Abstract] [Full Text] [PDF]

				B.D. Boyan, V.L. Sylvia, D.D. Dean, F. Del Toro, and Z. Schwartz DIFFERENTIAL REGULATION OF GROWTH PLATE CHONDROCYTES BY 1{alpha},25-(OH)2D3AND 24R,25-(OH)2D3 INVOLVES CELL-MATURATION-SPECIFIC MEMBRANE-RECEPTOR-ACTIVATED PHOSPHOLIPID METABOLISM Crit. Rev. Oral. Biol. Med., March 1, 2002; 13(2): 143 - 154. [Abstract] [Full Text]

				D. KIEPE, D. L. ANDRESS, S. MOHAN, L. STANDKER, T. ULINSKI, R. HIMMELE, O. MEHLS, and B. TONSHOFF Intact IGF-Binding Protein-4 and -5 and Their Respective Fragments Isolated from Chronic Renal Failure Serum Differentially Modulate IGF-I Actions in Cultured Growth Plate Chondrocytes J. Am. Soc. Nephrol., November 1, 2001; 12(11): 2400 - 2410. [Abstract] [Full Text] [PDF]

				J. Guo, B. Lanske, B.-Y. Liu, P. Divieti, H. M. Kronenberg, and F. R. Bringhurst Signal-Selectivity of Parathyroid Hormone (PTH)/PTH-Related Peptide Receptor-Mediated Regulation of Differentiation in Conditionally Immortalized Growth-Plate Chondrocytes Endocrinology, March 1, 2001; 142(3): 1260 - 1268. [Abstract] [Full Text] [PDF]

				U. QUERFELD, M. M. HOFFMANN, G. KLAUS, F. EIFINGER, M. ACKERSCHOTT, D. MICHALK, and P. A. KERN Antagonistic Effects of Vitamin D and Parathyroid Hormone on Lipoprotein Lipase in Cultured Adipocytes J. Am. Soc. Nephrol., October 1, 1999; 10(10): 2158 - 2164. [Abstract] [Full Text]

				A. COBO, J. LÓPEZ, E. CARBAJO, F. SANTOS, J. ALVAREZ, M. FERNÁNDEZ, and A. WERUAGA Growth Plate Cartilage Formation and Resorption Are Differentially Depressed in Growth Retarded Uremic Rats J. Am. Soc. Nephrol., May 1, 1999; 10(5): 971 - 979. [Abstract] [Full Text]

				C. Jux, K. Leiber, U. Hugel, W. Blum, C. Ohlsson, G. Klaus, and O. Mehls Dexamethasone Impairs Growth Hormone (GH)-Stimulated Growth by Suppression of Local Insulin-Like Growth Factor (IGF)-I Production and Expression of GH- and IGF-I-Receptor in Cultured Rat Chondrocytes Endocrinology, July 1, 1998; 139(7): 3296 - 3305. [Abstract] [Full Text] [PDF]

				S. Rihani-Bisharat, G. Maor, and D. Lewinson In Vivo Anabolic Effects of Parathyroid Hormone (PTH) 28-48 and N-Terminal Fragments of PTH and PTH-Related Protein on Neonatal Mouse Bones Endocrinology, March 1, 1998; 139(3): 974 - 981. [Abstract] [Full Text] [PDF]

				M. Amling, L. Neff, S. Tanaka, D. Inoue, K. Kuida, E. Weir, W. M. Philbrick, A. E. Broadus, and R. Baron Bcl-2 Lies Downstream of Parathyroid Hormone-related Peptide in a Signaling Pathway That Regulates Chondrocyte Maturation during Skeletal Development J. Cell Biol., January 13, 1997; 136(1): 205 - 213. [Abstract] [Full Text] [PDF]