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

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.

Medienart:

Artikel

Erscheinungsjahr:

1994

Erschienen:

1994

Enthalten in:

Zur Gesamtaufnahme - volume:135

Enthalten in:

Endocrinology - 135(1994), 4 vom: 15. Okt., Seite 1307-15

Sprache:

Englisch

Beteiligte Personen:

Klaus, G [VerfasserIn]
von Eichel, B [VerfasserIn]
May, T [VerfasserIn]
Hügel, U [VerfasserIn]
Mayer, H [VerfasserIn]
Ritz, E [VerfasserIn]
Mehls, O [VerfasserIn]

Themen:

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
10028-17-8
12583-68-5
1CC1JFE158
84477-87-2
9007-49-2
98600C0908
Calcitriol
Cyclic AMP
Cycloheximide
DNA
Dactinomycin
E0399OZS9N
FXC9231JVH
Isoquinolines
Journal Article
NI40JAQ945
Parathyroid Hormone
Parathyroid hormone (1-34), bovine
Parathyroid hormone (28-48)
Peptide Fragments
Piperazines
Protein Kinase Inhibitors
Receptors, Calcitriol
Research Support, Non-U.S. Gov't
Tetradecanoylphorbol Acetate
Thymidine
Tritium
VC2W18DGKR

Anmerkungen:

Date Completed 24.10.1994

Date Revised 21.11.2013

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM074992104