Reduction of serum serotonin precursors after veralipride treatment for postmenopausal hot flushes.

Objective: The pathogenesis of hot flushes involves several brain neurotransmitter systems, and changes in serotonin turnover have been hypothesized. Veralipride is an anti-dopaminergic agent that relieves hot flushes and putatively also modulates serotonergic neurons. To further elucidate this relationship, in the present study we evaluated whether administration of veralipride for relief of hot flushes is able to affect serum levels of the serotonin precursor tryptophan in postmenopausal women.

Serum levels of tryptophan, 5-hydroxytryptophan and serotonin in patients affected with different forms of amenorrhea.

Tryptophan (Trp) is present in the serum, partly bound to albumine and in the free form. The unbound portion of circulating tryptophan has the property of crossing the hematoencephalic barrier and being converted within the brain into serotonin (5-HT) through the enzymatic processes of hydroxylation and decarboxylation. The serotoninergic system plays an important role in neuroendocrine control of reproductive hormone secretion, and in particular, it may influence GnRH pulsatility, a function essential for reproductive processes.

Menopause alters the metabolism of serum serotonin precursors and their correlation with gonadotropins and estradiol.

Objective: Tryptophan, the serotonin (5-HT) precursor, is circulating in blood in both free (FT) and protein-bound forms. The free form crosses the hematoencephalic barrier and is converted into 5-HT. During the fertile years, tryptophan levels are negatively correlated to gonadotropin concentrations.

Serum fluctuations of total and free tryptophan levels during the menstrual cycle are related to gonadotrophins and reflect brain serotonin utilization.

Background: Serotoninergic (5-HT) neurons are suggested to regulate estrous cycle in animal models. In the present study we evaluated whether a relationship exists between the serotoninergic precursors in the central nervous system and the gonadotrophin-ovarian cyclic function.

Methods: We measured 5-HT precursors [free (FT) and total (TT) tryptophan] and LH, FSH and 17beta-estradiol (E2) levels in the serum of 15 fertile women with normal menstrual cycles during the follicular (cycle days 1-5, 7-11), mid-cycle (cycle days 14-16) and luteal (cycle days 17-19, 22-24) phases.

Serum tryptophan and 5-hydroxytryptophan at birth and during post-partum days.

Serum levels of tryptophan (Trp) and 5-hydroxytryptophan (5-HTP) were measured in the mother at birth, by normal delivery or cesarean section, on days 1 and 3 post-partum, and in the cord blood of the fetus-newborns. Decreases in Trp and 5-HTP levels during delivery were noted. Conversely, Trp levels in the cord blood of fetus-newborns were significantly higher than those of their mothers, and 5-HTP levels also showed a tendency to increase , whereas on day 1 post-partum Trp values were lower than those in fetal cord, but higher than those during spontaneous delivery.