Prevention of puerperal lactation by a single oral administration of the new prolactin-inhibiting drug, cabergoline.

To evaluate the efficacy of a single oral administration of the new ergot derivative Cabergoline in the prevention of post-partum lactation, we compared the effects of three different doses of the drug with those of placebo in 32 puerperal women. In a controlled, double-blind trial, the subjects were randomly allocated to four treatment groups receiving either placebo or 400, 600, or 800 micrograms Cabergoline (N = 8 in each group) within 24 hours after delivery. Treatment efficacy was assessed clinically by physical examination before (day 0) and at one, two, three, four, and 14 days after treatment. Plasma prolactin (PRL) concentrations were measured in blood samples collected before and at one, two, three, and four days after treatment. Lactation was prevented in four of the eight subjects (50%) who received 400 micrograms Cabergoline and in all subjects who received 600 or 800 micrograms Cabergoline. By contrast, only one of the eight subjects (12.5%) receiving placebo showed no signs of spontaneous lactation within the 14 days after delivery. No effects of placebo administration on plasma PRL levels were observed. Plasma PRL concentrations were significantly reduced starting from one day after Cabergoline administration, however, and the amount of inhibition of PRL secretion induced by different doses of the drug was not statistically different. These preliminary data demonstrate that Cabergoline has a dose-related effect in the prevention of postpartum lactation, and milk secretion can be prevented completely by a single oral administration of 600 or 800 micrograms of the drug

Prevention of puerperal lactation by a single oral administration of the new prolactin-inhibiting drug, cabergoline.

To evaluate the efficacy of a single oral administration of the new ergot derivative Cabergoline in the prevention of post-partum lactation, we compared the effects of three different doses of the drug with those of placebo in 32 puerperal women. In a controlled, double-blind trial, the subjects were randomly allocated to four treatment groups receiving either placebo or 400, 600, or 800 micrograms Cabergoline (N = 8 in each group) within 24 hours after delivery. Treatment efficacy was assessed clinically by physical examination before (day 0) and at one, two, three, four, and 14 days after treatment. Plasma prolactin (PRL) concentrations were measured in blood samples collected before and at one, two, three, and four days after treatment. Lactation was prevented in four of the eight subjects (50%) who received 400 micrograms Cabergoline and in all subjects who received 600 or 800 micrograms Cabergoline. By contrast, only one of the eight subjects (12.5%) receiving placebo showed no signs of spontaneous lactation within the 14 days after delivery. No effects of placebo administration on plasma PRL levels were observed. Plasma PRL concentrations were significantly reduced starting from one day after Cabergoline administration, however, and the amount of inhibition of PRL secretion induced by different doses of the drug was not statistically different. These preliminary data demonstrate that Cabergoline has a dose-related effect in the prevention of postpartum lactation, and milk secretion can be prevented completely by a single oral administration of 600 or 800 micrograms of the drug

Involvement of endogenous gabaergic system in the modulation of gonadotropin secretion in normal cycling women.

To investigate whether endogenous GABA participates in the control of gonadotropin secretion during the menstrual cycle, placebo or sodium valproate (DPA), an anticonvulsant drug which enhances endogenous GABA content by blocking GABA degradation, were administered to regularly cycling women both during early follicular and midluteal phase. In a first set of experiments, the effect of DPA administration (400 mg, orally) on basal gonadotropin secretion was evaluated in 13 subjects. During early follicular phase (n = 6), no significant changes in plasma gonadotropin levels were observed after DPA or placebo administration. Conversely, during midluteal phase (n = 7), DPA administration resulted in a significant fall (p less than 0.01) in plasma LH concentrations, with a maximal percent decrease of 41.8 +/- 6.7% after 120 min. No changes in plasma FSH levels were observed. In a second set of experiments, the effect of DPA pretreatment (400 mg, orally) on gonadotropin release stimulated by a pulse of exogenous GnRH (10 micrograms, iv bolus) was studied in 11 subjects. During both follicular (n = 4) and luteal phase (n = 7), DPA did not modify gonadotropin response to GnRH injected 1h after pretreatment. Finally, 8 subjects were submitted to iv injection with 10 micrograms GnRH 2h after pretreatment with DPA (400 mg, orally) or placebo. During both follicular (n = 4) and luteal phase (n = 4), no statistical differences in gonadotropin response to GnRH were found between DPA and placebo pretreatment. These findings demonstrated that during the estrogen-progesterone (midluteal) phase of menstrual cycle, endogenous GABA is involved in the inhibitory regulation of LH secretion at a central level

Neuroendocrinologia degli stati iperprolattinemici

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Dose-related prolactin inhibitory effect of the new long-acting dopamine receptor agonist cabergoline in normal cycling, puerperal, and hyperprolactinemic women.

Two different single doses (400 and 600 micrograms) of the new long-acting dopamine agonist cabergoline (CBG) were given to 12 normal cycling women, 17 puerperal women, and 24 hyperprolactinemic women (12 with idiopathic hyperprolactinemia and 12 with pituitary adenoma). Plasma PRL was determined in blood samples collected before and at frequent intervals for 5 days after CBG administration. Both CBG doses induced marked inhibition of PRL secretion in all women. A decrease in plasma PRL levels was evident 1-2 h after CBG administration and persisted for up to 5 days. The 600-micrograms CBG dose had a more potent (P less than 0.05) PRL inhibitory effect than the 400-micrograms dose in normal, puerperal, and hyperprolactinemic women. Moreover, while 400 micrograms CBG prevented lactation in 3 of 7 puerperal women, 600 micrograms CBG prevented lactation in 5 of 5 puerperal women. A moderate blood pressure decrease occurred 3-6 h after CBG treatment, but no other side-effects occurred. These results demonstrate that CBG induces a dose-related inhibition of PRL secretion in normal women as well as in puerperal and hyperprolactinemic women. The potent long-lasting PRL inhibitory effect of CBG in conjunction with the absence of side-effects typical of dopaminergic compounds suggest that this drug is an advance in the medical treatment of hyperprolactinemia

Effects of the GABAergic drug, sodium valproate, on the prolactin release evoked by pharmacological stimuli in normal women.

Sodium valproate (DPA or Na-dipropylacetate), an anticonvulsant drug activating the endogenous GABAergic system, was administered orally at the dose of 400 mg to seventeen normal women 1 h before intravenous injections with three drugs which stimulate prolactin (PRL) release: TRH (200 micrograms bolus; six subjects); domperidone (5 mg bolus; six subjects); and sulpiride (5 mg bolus; five subjects). DPA pretreatment significantly blunted PRL response to both domperidone and sulpiride injections without affecting the PRL response to TRH. In particular, the quantitative PRL secretion (areas under curves) following domperidone and sulpiride tests appeared significantly reduced after DPA treatment in comparison to placebo (P less than 0.02 and P less than 0.01 for domperidone and sulpiride respectively). These results indicate that the pharmacological enhancement of the endogenous GABAergic system by DPA may blunt PRL response to both central and peripheral dopamine receptor blockade. These observations suggest that a GABAergic pathway inhibiting PRL secretion at the hypothalamic level competes, at least in part, with the dopaminergic system. Conversely, the lack of any effect of DPA on PRL response to TRH seems to suggest that pituitary TRH receptors are independent of any GABAergic contr

Bromocriptine in the treatment of postmenopausal hot flushes

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Involvement of endogenous gabaergic system in the modulation of gonadotropin secretion in normal cycling women.

To investigate whether endogenous GABA participates in the control of gonadotropin secretion during the menstrual cycle, placebo or sodium valproate (DPA), an anticonvulsant drug which enhances endogenous GABA content by blocking GABA degradation, were administered to regularly cycling women both during early follicular and midluteal phase. In a first set of experiments, the effect of DPA administration (400 mg, orally) on basal gonadotropin secretion was evaluated in 13 subjects. During early follicular phase (n = 6), no significant changes in plasma gonadotropin levels were observed after DPA or placebo administration. Conversely, during midluteal phase (n = 7), DPA administration resulted in a significant fall (p less than 0.01) in plasma LH concentrations, with a maximal percent decrease of 41.8 +/- 6.7% after 120 min. No changes in plasma FSH levels were observed. In a second set of experiments, the effect of DPA pretreatment (400 mg, orally) on gonadotropin release stimulated by a pulse of exogenous GnRH (10 micrograms, iv bolus) was studied in 11 subjects. During both follicular (n = 4) and luteal phase (n = 7), DPA did not modify gonadotropin response to GnRH injected 1h after pretreatment. Finally, 8 subjects were submitted to iv injection with 10 micrograms GnRH 2h after pretreatment with DPA (400 mg, orally) or placebo. During both follicular (n = 4) and luteal phase (n = 4), no statistical differences in gonadotropin response to GnRH were found between DPA and placebo pretreatment. These findings demonstrated that during the estrogen-progesterone (midluteal) phase of menstrual cycle, endogenous GABA is involved in the inhibitory regulation of LH secretion at a central level