[EGF binding site number of rat anterior pituitary is increased by chronic administration with dopaminergic agonist, CV 205-502].
In order to assess whether a chronic treatment with a dopamine agonist, CV205-502, could modulate anterior pituitary epidermal growth factor (EGF) binding sites, female Wistar rats were treated or not (controls) with CV205-502 0.25 mg/kg/day sc for 8 days. This treatment significantly reduced rats' pituitary weight and plasma prolactin levels when compared to controls (weight: 10.4 +/- 0.1 vs 11.1 +/- 0.1 mg, p less than 0.01; prolactin: 1.2 +/- 0.2 vs 4.9 +/- 0.5 ng/ml, p less than 0.01). These decreases were associated with a significant stimulation of the number of pituitary EGF binding sites Bmax: 16.7 +/- 2.3 vs 11.3 +/- 1.9 fmoles/mg proteins, p less than 0.01) with no significant effect on their affinity (Kd: 0.94 +/- 0.17 vs 0.95 +/- 0.14 nM). Therefore, the modulation of pituitary EGF binding sites might be one of the mechanisms by which the dopamine agonist, CV205-502, exerts its pharmacological effects on hormonal secretions and/or cell multiplication in the pituitary.
I.N.S.E.R.M. U. 223, Faculté de Médecine Pitié-Salpêtrière, Paris.
P
P
Birman
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F
Bai-Grenier
D
D
Joubert
D000634:Aminoquinolines / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005260:Female; D007279:Injections, Subcutaneous; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D000634:Aminoquinolines; D015259:Dopamine Agents; D004815:Epidermal Growth Factor; C046650:quinagolide; D011388:Prolactin
Le nombre de sites EGF de l'antéhypophyse du rat est augmenté par l'administration chronique de l'agoniste dopaminergique, le CV 205-502.