Chloroquine therapy reduces oestrogen production in females

In this study: it has been shown that chloroquine therapy reduces both testosterone and oestradiol secretion in females. This reduction was marked the longer the duration of exposure to the drug. The animals did not regain the pretreatment sex hormone levels even after they were left for one month to recover without chloroquine intake. It seems that the inhibitory effect of chloroquine is mediated through the production of epidermal growth factor (EGF). This latter exerts an inhibitory effect on the LH Lutenzing hormone receptors in ovarian granulosa cells. EGF has also got a suppressive effect on 17 a-hydroxylase enzyme; a key enzyme which is necessary for the hydroxylation of pregnenolone and progesterone in the ovary Hydroxy pregnenolone is a precursor of androstendione, while 17 a-hydroxyprogesterone is a precursor of testosterone. Both androgens (androstendione and testosterone) are aromatized to oestrogens in the gonadal and extragonadal tissues. This study draws the attention to prolonged chloroquine therapy in collagen disorders. In such diseases as the drug is used on long term basis, it should be used with utmost care specially in old female patients who are already candidates for oestrogen hormonal replacement therapy to protect their fragile status.