EFFECTS OF OESTRADIOL-17β BENZOATE TREATMENT ON FRACTURE HEALING AND BONE COLLAGEN SYNTHESIS IN FEMALE RATS

1975 ◽  
Vol 80 (3) ◽  
pp. 603-612 ◽  
Author(s):  
Norvald Langeland
Keyword(s):  
Tensile Strength ◽  
Young Adult ◽  
Collagen Synthesis ◽  
Specific Activity ◽  
Female Rats ◽  
Bone Collagen ◽  
Fracture Region ◽  
Significant Difference ◽  
High Doses ◽  
Bone Collagen Synthesis

ABSTRACT The influence of oestradiol-17β benzoate, 70 μg administered intramuscularly twice a week for up to four weeks, on collagen synthesis in fractured bones, was studied in young adult castrated female rats. The specific activity of [14C] hydroxyproline in the fracture region of the treated rats was constantly below that of the normal and the castrated control animals throughout the experimental periods. The percentage of incorporated 14C found as [14C] hydroxyproline was also reduced in the fracture regions of the oestrogen treated rats compared to the percentage observed in normal rats. During the first two weeks after fracture and the start of treatment, there was no differences in tensile strength of the fractures and no significant difference in collagen content of the fractured tibia of the 3 experimental groups. The weights of the unfractured tibiae in oestrogen treated rats were lower than those of the control animals. The findings suggest a "slow down" of collagen metabolism after administration of high doses of oestradiol.

IN VITRO STUDIES ON COLLAGEN METABOLISM IN METAPHYSEAL RAT BONE

1975 ◽  
Vol 80 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Norvald Langeland ◽  
Vigdis Teig
Keyword(s):  
Collagen Synthesis ◽  
Mature Female ◽  
Parathyroid Glands ◽  
Collagen Metabolism ◽  
Female Rats ◽  
Bone Collagen ◽  
Detectable Effect ◽  
Bone Collagen Synthesis ◽  
Rat Bone

ABSTRACT Oestradiol-17β has been administered to hypophysectomized/castrated and to thyro-parathyroidectomized/castrated young mature female rats. Treatment with oestradiol-17β 5 μg/day per animal, was continued for 3 weeks. Bone pieces from tibia/femur metaphyses were incubated in vitro for 3 h in order to establish the bone collagen synthesis and resorption rates. The results were compared to results from a previous study on castrated female rats with intact hypophysis, thyroid and parathyroid glands. Bone from the thyro-parathyroidectomized/castrated rats treated with oestradiol-17β had a significantly reduced collagen resorption rate in vitro as compared to their paired controls. This is a result consistent with that of castrated female rats with intact thyroid and parathyroid glands treated with oestradiol. Oestradiol-17β had no detectable effect upon collagen metabolism in the hypophysectomized/castrated rats. It is concluded that the effect of oestradiol on bone resorption is not exerted via the parathyroid glands or parathyroid hormone. The possibility that oestrogens may act on bone via the hypophysis is discussed.

scholarly journals Vitamin A and bone formation. Effect of an excess of retinol on bone collagen synthesis in vitro

1985 ◽  
Vol 226 (3) ◽  
pp. 789-795 ◽  
Author(s):  
I Dickson ◽  
J Walls
Keyword(s):  
Bone Formation ◽  
Collagen Synthesis ◽  
Bone Collagen ◽  
Dependent Manner ◽  
Stimulate Bone Resorption ◽  
Dna And Rna ◽  
A Cell ◽  
Dose Dependent ◽  
Bone Collagen Synthesis

The influence of an excess of retinol on bone formation was studied by using cultures of embryonic-chick calvaria. Retinol decreased collagen synthesis in a dose-dependent manner, non-collagenous protein synthesis being relatively unaffected. Collagen synthesis was significantly inhibited after 24 h of culture with retinol and was progressively decreased, compared with control cultures containing no retinol, as the period of culture was increased. The effect of retinol on collagen synthesis could be reversed by incubation of calvaria for further periods in retinol-free medium. Incorporation of [3H]thymidine and [3H]uridine into DNA and RNA respectively was not altered by culturing calvaria with retinol for 22 h. These latter findings, and the selectivity for collagen synthesis, all suggested that the effect observed was not a cell-toxicity phenomenon. The effect of retinol on collagen synthesis by chick calvarial osteoblasts was probably direct and not mediated by osteoclasts, since a negligible number of the latter cells is present in chick calvaria. In cultures of neonatal murine calvaria, which contain many osteoclasts, retinol similarly inhibited synthesis of collagen, but not of non-collagenous protein; the concentrations of retinol necessary to produce the response were similar to those required to stimulate bone resorption in vitro.

Effects of Glucocorticoids on Fetal Rat Bone Collagen Synthesis in Vitro*

Endocrinology ◽  
1979 ◽  
Vol 104 (3) ◽  
pp. 715-721 ◽  
Author(s):  
JOHN W. DIETRICH ◽  
ERNESTO M. CANALIS ◽  
DONNA M. MAINA ◽  
LAWRENCE G. RAISZ
Keyword(s):  
Collagen Synthesis ◽  
Bone Collagen ◽  
Fetal Rat ◽  
Bone Collagen Synthesis ◽  
Rat Bone

Hormonal Control of Bone Collagen Synthesis in Vitro. Effects of Insulin and Glucagon*

Endocrinology ◽  
1977 ◽  
Vol 100 (3) ◽  
pp. 668-674 ◽  
Author(s):  
ERNESTO M. CANALIS ◽  
JOHN W. DIETRICH ◽  
DONNA M. MAINA ◽  
LAWRENCE G. RAISZ
Keyword(s):  
Collagen Synthesis ◽  
Hormonal Control ◽  
Bone Collagen ◽  
In Vitro Effects ◽  
Bone Collagen Synthesis

Effect of somatomedin and growth hormone on bone collagen synthesis in vitro

Metabolism ◽  
1977 ◽  
Vol 26 (10) ◽  
pp. 1079-1087 ◽  
Author(s):  
Ernesto M. Canalis ◽  
Raymond L. Hintz ◽  
John W. Dietrich ◽  
Donna M. Maina ◽  
Lawrence G. Raisz
Keyword(s):  
Growth Hormone ◽  
Collagen Synthesis ◽  
Bone Collagen ◽  
Bone Collagen Synthesis

THE EFFECT OF DIFFERENT DOSES OF OESTRADIOL-17β ON COLLAGEN SYNTHESIS IN THE FEMUR OF CASTRATED FEMALE RATS

1975 ◽  
Vol 80 (3) ◽  
pp. 613-624 ◽  
Author(s):  
Norvald Langeland
Keyword(s):  
Specific Activity ◽  
Mature Female ◽  
The Body ◽  
Collagen Metabolism ◽  
Collagen Content ◽  
Female Rats ◽  
Bone Collagen ◽  
Tissue Fluid ◽  
Body Weights ◽  
Different Doses

ABSTRACT The effect of different doses of oestradiol-17β on collagen metabolism in the femur of castrated young mature female rats was studied. The animals received daily injections of the hormone for 21 days and 25 μCi [14C]proline was injected intraperitoneally 24 h before the rats were sacrificed. The rats receiving 1 μg oestradiol per day had a significantly higher specific activity of hydroxyproline in bone compared to the normal and the castrated control rats. At the same time the bone weights and collagen content per femur were less in the rats receiving oestradiol 1 and 2 μg/day than in the control animals. The higher specific activity of bone hydroxyproline in the rats receiving oestradiol-17β 1 μg/day did not, however, indicate a higher bone collagen accretion rate. As all rats received the same amount of [14C] proline, and the body weights differed considerably at sacrifice, the animals probably had different tissue fluid concentrations of [14C] proline. This possibility was supported by the observation that serum concentrations of radioactivity were inversely correlated to body weights. "Correcting" for differences in body weights, the castrated control rats turned out to be the group with the highest specific activity. On doses of 10 and 20 μg oestradiol-17β per day, the specific activity of hydroxyproline in bone was lower than in the control rats while bone weights and collagen content of the femur were not different from the corresponding values of the castrated controls. This finding suggests a "slow down" of collagen metabolism – both with regard to the accretion and the resorption. At high doses – 10 and 20 μg oestradiol per animal per day – the percentage of incorporated 14C found as [14C]hydroxproline was reduced. The reason for this altered total-C14/[14C]hydroxyproline ratio is at present unknown.

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