2-Br-α-Ergokryptin: Beeinflussung von Fertilität und Laktation bei der Ratte

Flückiger, E.; Wagner, H.

doi:10.1007/bf02147804

Cited by 159 publications

(36 citation statements)

References 4 publications

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“…It was developed originally to investigate whether metoclopramide would inr of prolactin secretion (12), crease adrenocortical sensitivity to angiotensin. Howrecognized to be a dopamine ever, we were not able to demonstrate any difference nocriptine has been demon-in the angiotensin-aldosterone dose-response curves pamine agonist in the central after metoclopramide.…”

Section: Discussionmentioning

confidence: 99%

“…The subjects were placed on a constant diet containing 150 meq of sodium, 60 meq of potassium, 1 g of protein/kg and 2,860 cal/day for 5 d at the Clinical Research Center before the studies. Consecutive 24 h urine samples were collected for the first 4 d of the diet and consecutive 12 h urine samples were collected for the remainder of each study and were analyzed for sodium, potassium, and creatinine. No food was given after midnight before study day 1 when the subjects assumed the supine position until completion of each study.…”

Section: Methodsmentioning

confidence: 99%

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Effects of Metoclopramide and Bromocriptine on the Renin-Angiotensin-Aldosterone System in Man

Carey¹,

Thorner²,

Ortt³

1979

J. Clin. Invest.

231

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A B S T R A C T This study was designed to investigate the possible role of dopaminergic mechanisms in the control ofthe renin-angiotensin-aldosterone system in normal man. Six normal male subjects in metabolic balance at 150 meq sodium, 60 meq potassium constant intake received the specific dopamine antagonist, metoclopramide, 10 mg i.v. or placebo followed by angiotensin II infusion 1 h later on 2 consecutive days. Metoclopramide increased plasma aldosterone concentration from 8.2+2.2 to 21.0+3.3 ng/100 ml (P <0.005) and plasma prolactin concentration from 18.0±4.0 to 91.7+4.0 nglml (P < 0.001) within 15 min of its administration. At 1 h, plasma aldosterone and prolactin concentrationis remained elevated at 16.8 ±2.1 ng/100 ml (P < 0.01) and 86.8±+15.9 ng/ml (P < 0.005), respectively. Angiotensin II at 2, 4, and 6 pmol/kg per miim further increased plasma aldosterone concentration to 27.2+3.4, 31.9+5.7, and 36.0+6.7 ng/100 ml (P < 0.02), respectively. Placebo did not alter plasma aldosterone or prolactin concentrations, but angiotensin II increased plasma aldosterone concentration to 13.7±2.4, 19.0+ 1.9, and 23.3+3.2 ngIl00 ml (P < 0.005). The increment of plasma aldosterone concentration in response to angiotensin II was similar after metoclopramide or placebo.The six subjects also received the dopamine agonist, bromocriptine, 2.5 mg or placebo at 6 p.m., midnight, and 6 a.m. followed by angiotensin II infusion on 2 consecutive d. Bromocriptine suppressed prolactin to <3 ng/ml. After placebo, plasma aldosterone concentration increased from 5.2± 1.4 to 12.3+1.7, 17.2 +2.2, and 21.8+3.5 ng/100 ml (P < 0.01) and after bromocriptine from 7.2±1.0 to 14.7+. and 23.4±1.6 ng/100 ml (P < 0.001) with each respective angiotensin II dose. No difference in the response to angiotensin II after bromocriptine or placebo was observed. Plasma renin activity, free 11-hydroxycorticoid concentration, and serum potassium concentration were unchanged by metoclopramide or bromocriptine.The results suggest that aldosterone production is under maximum tonic dopaminergic inhibition which can be overridden with stimulation by angiotensin II in normal man. INTRODUCTION Dopamine, a precursor of the sympathetic neurotransmitter norepinephrine, may itself be a major transmitter of the peripheral autonomic nervous system (1). The adrenergic component of this system is important in controlling renin release (2, 3), but little is known concerning the role of dopamine in the regulation of the renin-angiotensin-aldosterone system. Cuche et al. (4) have shown in man that the increase in plasma renin activity with upright posture is associated with a decrease in urinary dopamine and an increase in norepinephrine and epinephrine excretion. Alexander and colleagues (5) have reported that sodium-depleted subjects respond to dietary or intravenous sodium loading with an increase in urinary dopamine and a decrease in urinary norepinephrine. Thus, maneuvers which would be expected to alter the activity of the renin-angiotensin-aldosterone system are ass...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effects of Metoclopramide and Bromocriptine on the Renin-Angiotensin-Aldosterone System in Man

Carey¹,

Thorner²,

Ortt³

1979

J. Clin. Invest.

231

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“…This drug has not only been used to suppress prolactin secretion in laboratory animals (Fluckiger and Wagner, 1968), but also in mature cyclic ewes (Niswender, 1974) and in ram lambs (Ravault et al, 1977). As shown in figure 1, ergocryptine was quite effective in reducing serum prolactin during summer anestrus; yet average interval to first estrus was almost identical to that recorded for control ewes.…”

Section: Discussionmentioning

confidence: 99%

Relationship of Daylength and Prolactin to Resumption of Reproductive Activity in Anestrous Ewes

Schanbacher¹

1980

Journal of Animal Science

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SummaryConcentrations of prolactin were measured in serum from three groups of Rambouillet ewes for 8 weeks to determine whether changes in prolactin concentrations were important during the transition from anestrus to seasonal breeding. Group I (control ewes) was maintained under conditions of natural daylength;group II (short-day ewes) was exposed abruptly on the longest day of the year to artificially shortened daylengths (8 hr light and 16 hr darkness); group III (CB 154 ewes) was maintained similar to control ewes except each ewe received twice daily im injections of 2-bromo,a-ergocryptine (CB 154). A fertile ram was kept with each group of ewes. Average serum prolactin remained above 200 ng/ml in control ewes throughout the 8-week study; however, short-day ewes had reduced (P<.05) serum prolactin and CB 154 ewes had low to nondetectable serum prolactin. Despite these differences, average interval to first estrus for the three groups of ewes was similar (control ewes, 25.2 + 3.0; short-day ewes, 23.5 + 2.9; CB 154 ewes, 26.4 + 4.3 days). Short-day and CB 154 treatments did have an apparent effect on interval to conception. Of those ewes that lambed, short daylengths advanced (P<.O1) the average date of conception by 7.7 days in relation to that of controls, whereas CB 154 treatment delayed ! The technical assistance of Ms. Becky Chmelka and Ms. Donna Taubenheim and cooperation of the Nebraska Agr. Exp. Sta., Univ. of Nebraska, Lincoln, is gr2atefully acknowledged.

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“…In 1978 Pawlikowski et al [3] showed that DA directly inhibits the pituitary growth The dopamine receptors, which are responsible for the direct effects of DA at the anterior pituitary level, were characterized as belonging to D2 type [for review see 4]. A synthesis of bromocriptine, a first selective and long-lasting agonist of D2 receptors, allowed to introduce this drug to the medical treatment of pituitary adenomas, particularly prolactinomas [5]. Nowadays bromocriptine and other newer D2 agonists consist a first line treatment for prolactinomas [6].…”

Section: Introductionmentioning

confidence: 99%

Immunohistochemical detection of dopamine D2 receptors in human pituitary adenomas.

Pawlikowski

2010

Folia Histochem Cytobiol.

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Thirty one pituitary adenomas and 3 samples of peritumoral anterior pituitary tissue were immunostained with an antibody raised against dopamine D2 receptor protein. The positive reactions were found in cell cytoplasm, a subpopulation of cell nuclei and the intratumoral blood vessels walls. As expected, the positive immunostaining was shown in cytoplasm and/or cell nuclei of all examined prolactinomas (7/7). In acromegaly the positive D2 staining occurred in 5/7 samples, in gonadotropinomas in 6/8 and in plurihormonal adenomas 2/4. The lowest expression was observed in corticotropinomas (1/5). These findings corroborate with the well known efficacy of D2 agonists in the treatment of prolactinomas and somatotropinomas, and support the rationale of the therapeutic trials with these compounds in gonadotropinomas. Moreover, the presence of D2 receptors in intratumoral blood vessels walls constitutes the possibility of the anti-angiogenic action of D2 agonists in pituitary adenomas.

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2-Br-α-Ergokryptin: Beeinflussung von Fertilität und Laktation bei der Ratte

Cited by 159 publications

References 4 publications

Effects of Metoclopramide and Bromocriptine on the Renin-Angiotensin-Aldosterone System in Man

Effects of Metoclopramide and Bromocriptine on the Renin-Angiotensin-Aldosterone System in Man

Relationship of Daylength and Prolactin to Resumption of Reproductive Activity in Anestrous Ewes

Immunohistochemical detection of dopamine D2 receptors in human pituitary adenomas.

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