Suppressive effect of glucose administration on the binding of prolactin by rat liver

Effects of hyperprolactinemia on plasma glucose and prolactin in rats exposed to ether stress

The present study was designed to characterize the effect of chronic hyperprolactinemia on plasma glucose and prolactin (PRL) during ether stress in male and female rats. Wistar rats of both sexes were divided into a hyperprolactinemic group (bearing pituitary grafts) and a control group (sham operated). They were exposed to ether during 10 min and had blood samples taken immediately before, and 5, 15, 40, and 70 min after ether exposure and assayed for glucose and PRL concentrations. Ether stress induced significant increase in plasma PRL of control rats at 5 min (male 171%, female 161%; P < 0.01), but only a mild PRL increase occurred in grafted rats (male 66%, female 62%; P < 0.05). Control male rats sustained elevated plasma PRL longer than females. There was a marked elevation of glucose levels at 5 min (P < 0.01) which peaked at 15 min in all groups. Grafted rats had glucose levels significantly above control at baseline (female 15%, P < 0.05) and at 40 min (male 25%, female 29%; P < 0.05). It is concluded that ether-induced PRL release produced a rapid and transient response, more intense in males than in females and which was impaired by previous hyperprolactinemia (pituitary grafts). There was an acute hyperglycemic response, plasma glucose being increased in grafted rats, supporting the hypothesis of a hyperglycemic effect of PRL.