Leptin regulation of monocytic oxidative and phagocytic activities in women in different phases of a menstrual cycle

Abstract

Leptin used in the doses comparable with the concentrations of the hormone in the first and second-third trimesters of pregnancy (10 and 35 ng/ml, respectively) was tested for effects on monocytic oxidative and phagocytic activities in vitro in women in different phases of a menstrual cycle. The hormone used in the test doses was found to inhibit the baseline monocytic production of active oxygen forms, when given in a high dose (35 ng/ml) it lowered the activity of secretory myeloperoxidase irrespective of the phase of a menstrual cycle. In the follicular phase of a menstrual cycle, leptin suppressed phagocytic activity when used in a low dose (10 ng/ ml) and reduced the monocytic production of active oxygen forms when used in the high dose in the induced luminol-dependent chemiluminescence (LDC). In the luteinlc phase, Leptin (10 and 35 ng/ml) exerted a stimulating effect on monocytic phagocytosis, but substantially decreased the extracellular production of active oxygen metabolites in LDC. Thus, leptin given in the doses comparable with the concentrations of the hormone in the first and second-third trimesters of pregnancy heterodirectionally modulates the oxidative and phagocytic activities of peripheral blood monocytes in fertile females in relation to the phase of a menstrual cycle.