Open AccessInfluence of Growth Hormone and Thyroxine On Cell Kinetics In the Proximal Tibial Growth Plate of Snell Dwarf Mice
Author(s) -
Smeets Ton,
BuulOffers Sylvia
Publication year - 1986
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.1986.tb00726.x
Subject(s) - labelling , mitosis , endocrinology , medicine , hormone , distribution (mathematics) , cell growth , cell division , chemistry , cell , growth hormone , thymidine , biology , biochemistry , microbiology and biotechnology , dna , mathematics , mathematical analysis
Abstract. In Snell dwarf mice, the influence of short‐term treatment with human growth hormone (hGH) or thyroxine on the proliferative and sulphation activity of the proximal tibial growth plate was studied. By autoradiographic methods, the [ 3 H]methylthymidine incorporation after a single injection was measured, after 2 hr incorporation time. the labelling index was calculated and the number of labelled mitoses was counted. In addition, the distribution of the labelled nuclei over the proliferating and degenerating zones was determined by continuous labelling for 25 and 73 hr. In untreated dwarf mice after [ 3 H]‐methylthymidine administration, the number of labelled nuclei in the growth plate is low. Labelling occurs, as expected, mainly in the cells of the proliferative zones. the number of labelled nuclei in control dwarf mice was similar after 25 and 73 hr continuous labelling. This suggests that many cells are in a resting G o or prolonged G 1 phase. Both hGH and T 4 treatment induce a significant increase of the number of labelled nuclei per growth plate and of the number of mitoses. Since hormonal treatment induces a small number of mitoses after 2 hr incorporation of the label, the minimal G 2 phase of the cell cycle is less than 2 hr. In addition, treatment with hGH and T 4 stimulates chondrocytes in the zone of proliferative and hypertrophic cells to actively incorporate [ 35 S]‐sulphate.