Effects Of Alcohol On Plasma Prolactin Level, Pituitary Wet Weights And Amino Acid Neurotransmitter In Hypothalamus Of Female Rats

Objective To discover the correlation between the concentration and age of alcohol consumption with plasma prolactin (PRL) level and discuss the mechanism of alcohol on Hyperprolactinemia (HP) from observing the effects of alcohol on plasma prolactin level, pituitary wet weights and amino acid neurotransmitter in hypothalamus homogenate of female rats. Moreover, observing the relation between alcohol consumption and HP is good at improving the etiologic research of HP and offering theoretical direction to the prevention and therapy of HP.Methods 1. Forty grown female SD rats on the same age were randomly divided into three alcoholic groups and one control group, ten in each group. The alcoholic groups involved administration of ethanol for 4 and 8 weeks using a liquid ingestion containing 10%,20% and 30% ethanol (v/v). The control group was pair-fed distilled water.2. Thirty female SD rats being four, six and eight weeks old were administrated with a liquid ingestion containing 20% ethanol (v/v) for 4 weeks and the control group was pair-fed distilled water. 3. Prolactin levels in plasma were detected using radioimmunoassay, pituitary wet weights were measured and amino acid neurotransmitter such as gamma-aminobutyric acid (GABA), glutamic (GLU) and glutamine (GLN) in hypothalamus homogenate were assayed using coulomb array electrochemistry high performance liquid chromatography(HPLC). The correlation between the concentration and age of alcohol consumption with plasma prolactin level, pituitary wet weights and amino acid neurotransmitter in hypothalamus was analysed.Results 1.30% ethanol treatment significantly increased the plasma prolactin levels and pituitary wet weights after 4 weeks alcohol consumption; the 10% and 20% alcoholic groups'plasma prolactin levels and pituitary wet weights were obviously higher than the 30% alcoholic group and control group after 8 weeks alcohol consumption. Compared to the 4 weeks treatment,10% and 20% ethanol significantly increased the plasma prolactin levels and pituitary wet weights after 8 weeks alcohol consumption. However, the 30% alcoholic group was reverse, the difference all had statistical significance, P<0.05.2. After 4 weeks alcohol consumption, the 20%and 30%alcoholic groups'GAB A concentration in hypothalamus homogenate were obviously lower than the control group; the 30%alcoholic group was obviously lower than the 10%and 20%alcoholic groups. After 8 weeks alcohol consumption, all of the three alcoholic groups were obviously lower than the control group; the 30%alcoholic group was obviously lower than the 10%and 20%alcoholic groups. Compared to the 4 weeks treatment,10%and 20%ethanol significantly decreased the GABA concentration in hypothalamus homogenate after 8 weeks alcohol consumption, the difference all had statistical significance, P<0.05.3. After 4 weeks alcohol consumption, the 30%alcoholic groups' GLU and GLN concentration in hypothalamus homogenate was obviously higher than the other three groups. After 8 weeks alcohol consumption, all of the three alcoholic groups'GLU concentration were obviously higher than the control group and the 20%and 30%alcoholic groups were obviously higher than the 10%alcoholic group; 20% alcoholic group's GLN concentration was obviously higher than the control group. Compared to the 4 weeks treatment,10%and 20%ethanol significantly increased and 30%ethanol significantly decreased the GLU concentration in hypothalamus homogenate after 8 weeks alcohol consumption; 20%ethanol significantly increased the GLN concentration; the difference all had statistical significance, P<0.05.4. After 4 weeks alcohol consumption with the same concentration, only the 4-weeks-old rats showed significantly higher plasma prolactin levels and pituitary wet weights, lower GABA and higher GLU concentration in hypothalamus homogenate than that of control group. The 8-weeks-old rats showed significantly lower GABA concentration, the difference all had statistical significance, P<0.05. However, the 6-weeks-old rats showed no statistical significance, P>0.05.Conclusion 1. Alcohol consumption can make influence on plasma prolactin level of female rats which depends on ethanol concentration and doses:Higher alcohol concentrations should increasded the plasma prolactin level within a relative short time. Long-term lower alcohol concentrations should obviously elevated the plasma prolactin level gradually.2. Long-term binge drinking may lead to the dysfunction of the prolactin secretion on pituitary gland.3. The plasma prolactin level could be more easily increased under alcohol consumption in juvenile stage.3. The results suggest that ethanol causes hyperprolactinemia by stimulated the hyperplasia of lactotropes in the anterior pituitary gland, suppressed GABA and promoted GLU of hypothalamus.