Abstract
The role of testosterone/17 B estradiol ratios (T/E), on the vasoconstrictor effect of norepinephrine (NE), were studied in strips of carotid arteries from dogs. T/E of 0.1 (T = 1 nM/E = 10 nM) shifted the concentration/effect (C-E) curve of NE to the right. T/E of 10 (T = 10 nM/E = 1 nM) deviated it to the left. T (1 nM and 10 nM) shifted the C-E curve of NE to the right; E = 1 nM did not modify it; E = 10 nM, shifted it to the left. In microsomal fraction of carotid arteries, adrenergic receptors were characterized with 3H-NE binding, and the role of T/E ratios also studied. Under the influence of T/E ratio of 10, the agonist affinity (Ka), was increased from 100 nM-1 to 128 nM-1, the receptors density (Bmax), increased from 78.3 nM to 148 nM. E (1 nM) reduced Ka to 88 nM-1, T did not change any of these parameters. In conclusion, T/E ratios of 10, as in male, may enhance the vasoconstrictor activity of NE, increasing Ka and Bmax of adrenergic receptors.
Translated title of the contribution | Changes in the vasoconstrictor action of noradrenaline and in its receptor-binding kinetics induced by sex hormones |
---|---|
Original language | Spanish |
Pages (from-to) | 407-411 |
Number of pages | 5 |
Journal | Archivos del Instituto de Cardiología de México |
Volume | 61 |
Issue number | 5 |
State | Published - 1991 |
Externally published | Yes |