Effect of histamine on basal and TRH/LH-RH-stimulated PRL and LH secretion during different phases of the menstrual cycle in normal women

The effect of histamine on progesterone and estradiol secretion of human granulosa cells in serum-free culture

The aim of this study was to explore the direct action of histamine on progesterone and estradiol secretion of human granulosa cells cultured in serum-free medium. Human granulosa cells were isolated from preovulatory follicular fluid aspirated from 17 women (32 +/- 3 years old, mean +/- SD) undergoing in vitro fertilization treatment at the University Women's Hospital of Tübingen. Progesterone and estradiol production was measured in the presence and absence of histamine, terfenadine or cimetidine using radioimmunoassays. Statistical analysis of the data was performed by analysis of variance and Newmann-Keul tests. Histamine stimulated a dose-related increase in estradiol secretion with a maximal stimulatory effect at 10(-3) mol/l. This response was blocked specifically by the H1-receptor antagonist terfenadine. Progesterone production in response to histamine stimulation was independent of dose at the limit of significance. The specific H2-receptor antagonist cimetidine did not block the stimulatory effect of histamine. We suggest that histamine has a direct stimulatory effect on steroid production of granulosa cells mediated via the H1-receptor. This effect may have a physiological role in the regulation of granulosa cell function during the menstrual cycle.

Pathophysiological implications of increased brain burden of histamine in protein malnutrition

The complex syndrome of protein-energy malnutrition (PEM) in weanling children, usually complicated by concurrent presence of numerous adverse environmental factors, is a chronic stressful situation which elicits a number of neuroendocrine and metabolic adjustments. Histidine metabolism is severely impaired in PEM in children and in experimental animals, and evidence from the latter indicate markedly increased body burden of histamine. The brain is the organ most prominently affected. Although data are still incomplete, histamine conforms with most criteria required of a neurotransmitter. Histamine interacts with other neuroregulatory substances in modulating many neuroendocrine and vegetative processes. Some of the prominent pathophysiological features associated with PEM in children such as increased circulating cortisol, defective thermoregulation, fluid/electrolyte imbalance, impaired immunity, reduced cardiac output with prolongation of systemic recirculation time, and apathy bordering on a clinical state of depression are consistent with the known effects of histamine as determined by neurochemical and neuropharmacological studies. It is suggested that studies of histamine status in human PEM, and the functional relationships between markedly elevated level of this amine with other neuroregulatory substances, will shed more light on the complex pathogenesis of the nutritional syndrome.