Abstract
The vitamin K-dependent coagulation factors II (prothrombin), VII (proconvertin), IX (Christmas-factor), and X (Stuart-factor) are all synthesized in the liver as proenzymes. The synthesis of other liver enzymes are affected by growth hormone (GH). To investigate whether GH affects the synthesis or metabolism of coagulation factors, hypophysectomized (hypox) male rats were treated with GH (mini-osmotic pumps) or daily injections of cortisone, thyroxine, vitamin K or saline (n=7-10). At day 11, all rats were cardiopunctured and the prothrombin complex (measures the activity of vitamin K-dependent coagulation factors), and the factors II, VII, IX, and X were determined. The prothrombin complex was 52.9±1.2% for shamoperated rats and 39.1 ± 0.8% for hypox rats receiving saline injections (mean±SEM; p<0.001). All vitamin K-dependent coagulation factors were decreased after hypophysectomy. However, this was significant only for factor VII decreasing from 264±23 to 131±9% (p<0.001) and factor IX decreasing from 28.4±2.2 to 17.1±2.5% (p<0.01). When hypox rats were treated with GH, the prothrombin complex increased to 50.9±1.0 % (p<0.001, compared to 39.1±0.8%) and the factor VII increased to 299±10% (p<0.001, compared to 131 ±9%). All the other factors were normalized after GH-treatment (data not shown). The injection of cortisone, thyroxine, or vitamin K to hypox rats had no effect. It can be concluded that GH is of great importance for normal blood coagulation in the male rat. GH-deficiency causes a decrease in the levels of vitamin K-dependent coagulation factors, especially factor VII, and the prothrombin complex.
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Sävendahl, L., Engström, K. & Grankvist, K. LOW PROCONVERTIN (FACTOR VII) AND IMPAIRED BLOOD CLOTTING DUE TO GROWTH HORMONE DEFICIENCY IN THE RAT. Pediatr Res 33 (Suppl 5), S63 (1993). https://doi.org/10.1203/00006450-199305001-00360
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DOI: https://doi.org/10.1203/00006450-199305001-00360