Neutralization by Acetyl Salicylic Acid of the Testosterone induced Impaired Maspin Synthesis Stimulated by Estriol in Neutrophils through Nitric Oxide Synthesis.
Parole chiave
Astratto
OBJECTIVE
Maspin, an anti breast cancer protein in the mammary cell and normal neutrophil has been reported to be synthesised by the stimulation of NO production induced by estriol. The role of testosterone was investigated in the synthesis of maspin in relation to that of estriol.
METHODS
Fifty normal female between the ages of 25-65 years old participated in the study. Maspin synthesis was demonstrated by in vitro translation of maspin mRNA, followed by the quantification of maspin by enzyme linked immune absorbent assay. NO was determined by methomoglobin method.
RESULTS
Incubation of the neutrophils in HBSS both with 30 nM estriol resulted in the synthesis of 1.8 ngm maspin with simultaneous increase of NO synthesis. In contrast incubating neutrophils with 20 nM testosterone in the presence of estriol inhibited maspin synthesis to 0.33 nM with simultaneous inhibition of NO synthesis from 1.89 nM to 0 nM at the same time. Addition of 0.2µM flutamide, a testosterone receptor blocker to the incubation mixture restored the synthesis of maspin by 60.64 %. Incubation of 25µM aspirin that stimulated NO synthesis restored the inhibition of maspin synthesis by testosterone by 79.1%. I-NAME, an inhibitor of nitric oxide synthase, abolished both maspin and NO synthesis. Scatchard plot of estriol binding in the presence of testosterone demonstrated that the male sex hormone inhibited the female sex hormone binding to its receptor by "cross talk" between the receptors. It was found that while 1.02 × 10(3) molecules of estriol bind each neutrophil at equilibrium, in the presence of testosterone (20nM) in the binding mixture decreases the binding of estriol to 0.5 × 10(3) with little change in the dissociation constant compared to controls.
UNASSIGNED
Estriol was found to stimulate maspin synthesis through the stimulation of NO, testosterone inhibited maspin synthesis through the inhibition of NO synthesis.
