ADIPOR1 and obesity due to melanocortin 4 receptor deficiency: The reduction in the expression of AdipoR1 in MCF-7 breast cancer cells corresponds with that proposed in the hypothesis of the present work, since in cells that received higher concentrations of leptin (100 ng/mL = excess weight-obesity; 1000 ng/mL), a decrease in the expression of mRNA of the gen was observed with regard to the control, while the cells that received stimulation with a concentration corresponding to normal weight showed an increase in the expression of both receptors.