Effects of growth hormone and insulin-like growth factor-I on colony formation of rabbit epiphyseal chondrocytes at different stages of maturation.
The effect of human GH (hGH) and insulin-like growth factor-I (IGF-I) on colony formation of rabbit epiphyseal tibial chondrocytes at different stages of maturation was studied in suspension culture. The epiphyseal growth plate from the proximal tibia of 8-week-old male rabbits was dissected and divided into three different (proximal, intermediate and distal) zones, each zone representing an enrichment of chondrocytes from the germinative, proliferative and hypertrophic cell layers respectively. Chondrocytes from these three zones were isolated by collagenase digestion and cultured in the presence of 10% (v/v) newborn calf serum in suspension stabilized with 0.5% (w/v) agarose for 14 days. The colonies were classified according to diameter and the number of colonies was estimated as a function of colony size (distribution of cloning efficiency). Cell clusters with a diameter of 56 micron or more were classified as colonies. The cloning efficiency (number of colonies formed per 1000 seeded cells) was 10.1 +/- 0.7 and 6.0 +/- 0.8 for chondrocytes isolated from the proximal and intermediate zones respectively. Insulin-like growth factor-I (25-200 ng/ml) increased the number of colonies in chondrocytes isolated from the proximal zone (122 +/- 9.0-156 +/- 8.4%; control value, 100%) and from the intermediate zone (136 +/- 14.0-191 +/- 29%). Low concentrations of hGH (10-40 ng/ml) stimulated colony formation in chondrocytes isolated from the proximal zone (125 +/- 6.4-137 +/- 7.9%) whereas a high concentration of hGH (160 ng/ml) was ineffective. Chondrocytes isolated from the intermediate zone showed no response to low concentrations of hGH (10-20 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Physiology, University of Göteborg, Sweden.
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Lindahl
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Nilsson
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Isaksson
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D013006:Growth Hormone / Q000502:physiology*; D006132:Growth Plate / Q000166:cytology / Q000254:growth & development*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D011817:Rabbits; D013002:Somatomedins / Q000502:physiology*
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone