| Autor: |
Martínez, M. P., Conti, M. I., Norese, M. F., Barceló, A. C., Alippi, R. M., Bozzini, C. E. |
| Zdroj: |
Comparative Haematology International; Dec2000, Vol. 10 Issue 3, p117-121, 5p |
| Abstrakt: |
An erythropoietin hypersecretory state (EPO-HS) has been defined as a condition evidenced in hypertransfused-polycythaemic rats and mice as a consequence of several treatments imposed before transfusion in which stimulated secretion of EPO is higher than in non-treated hypertransfused-polycythaemic controls at equal levels of polycythaemia. We have recently reported that sustained administration of testosterone induced the appearance of an EPO-HS in female mice, which was accompanied by kidney hypertrophy. Since the erythropoietic effect of androgens has been associated with the latter effect, the present study was performed to test the hypothesis that sustained administration of testosterone could induce an EPO-HS in the hypophysectomised rat model without concurrently increasing renal mass. Normal and hypophysectomised rats were injected with 5 mg of testosterone propionate, given three times per week by the subcutaneous route. Treatment started 90 days after hypophysectomy (performed when rats were 30 days old) to allow the erythropoietic system to reach steady-state conditions in the hypophysectomised animals before androgenic treatment began. The erythropoietic effect of testosterone in the hypophysectomised rats was demonstrated by normalisation of the circulating red cell volume at the end of the treatment period, whilst the undosed hypophysectomised controls gave values of 30% less than normal control rats. Testosterone administration produced a significant increase in renal weight in non-hypophysectomised rats, an effect that was negligible in the hypophysectomised animals. Some of the rats from all groups were hypertransfused at the end of the dosing period. Plasma EPO (pEPO) levels were not significantly different between undosed polycythaemic hypophysectomised and polycythaemic non-hypophysectomised rats exposed to hypobaria for 6 h. However, pEPO was significantly higher in response to exposure to hypobaria in both testosterone-treated hypophysectomised and non-hypophysectomised rats than in their corresponding untreated controls. Thus, data confirmed the hypothesis and suggest that the EPO-HS induced by testosterone should be considered non-specific and independent of kidney hypertrophy. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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