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Prolactin Concentration (prolactin + concentration)

Distribution by Scientific Domains
Medical Sciences87%

Kinds of Prolactin Concentration

  • plasma prolactin concentration
    		•

    Selected Abstracts

    Effects of long-term exposure to ramelteon, a melatonin receptor agonist, on endocrine function in adults with chronic insomnia

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2009
    Gary Richardson
    Abstract Objective To evaluate the effects of ramelteon, an MT1/MT2 melatonin receptor agonist used to treat insomnia, on endocrine function in adults with chronic insomnia. Methods This was a double-blind, placebo-controlled, trial of adults (18,45 years) with chronic insomnia. Subjects received either ramelteon 16,mg or placebo nightly for 6 months. Hormonal measures of the thyroid, reproductive, and adrenal axes were analyzed monthly and compared with baseline and placebo values. Results While isolated changes were detected at some time points, there were no consistent statistically significant differences between treatments on measures of thyroid function (total T4, free T4, TSH, and total T3), adrenal function (AM cortisol, and ACTH), or on most reproductive endocrine measures [LH, FSH, estradiol (women), total, and free testosterone (men)]. Prolactin concentrations were increased overall in women in the ramelteon group compared with placebo (p,=,0.003). No clinical effects of elevated prolactin were reported; average menstrual cycle length, duration of menses, and ovulation probability did not differ between groups. Conclusions Long-term exposure to ramelteon 16,mg, a potent melatonin receptor agonist, resulted in mild, transient increase in prolactin, in women only, that were not associated with measurable reproductive effects. There were no consistent changes in other endocrine measures. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Comparison of Selected Endocrine Parameters During Luteal Phase and Pregnancy in German Shepherd Dogs and Beagles

    REPRODUCTION IN DOMESTIC ANIMALS, Issue 2009
    AR Günzel-Apel
    Contents Concentrations of progesterone, prolactin and relaxin in serum at predetermined intervals after ovulation (day 0) in non-pregnant and pregnant normocyclic Beagles were assayed and results compared with those observed in German Shepherd dogs (GSD) in a previous study. The goal was to determine possible reproductive hormone specificities related to the GSD breed. Furthermore, the effects of medroxyprogesterone acetate (MPA)-treatment in non-pregnant Beagles and of progesterone supplementation in pregnant Beagles on the hormone concentrations were examined. Mean concentrations of progesterone and prolactin were not different in the non-pregnant Beagles compared with those seen in non-pregnant GSD, except at days 50,60, when progesterone concentrations were found to be higher in Beagles (p < 0.05). Mean progesterone concentrations in pregnant Beagles at days 50,60 after ovulation (day 0) were higher (p < 0.05) than in GSD at that time, but not at earlier time periods. Prolactin concentrations were higher (p < 0.05) in Beagles throughout pregnancy compared with those in the GSD. Mean relaxin concentrations were numerically but not significantly lower in GSD than in Beagles throughout pregnancy. A 10-day oral MPA treatment did not affect progesterone or prolactin secretion in normocyclic non-pregnant Beagles. Medroxyprogesterone acetate serum concentrations were approximately 3.9 ng/ml during treatment and decreased to 0.42 and 0.021 ng/ml within 5 and 15 days after end of treatment, respectively. Intramuscular progesterone supplementation from days 30 to 40 in pregnant Beagles resulted in higher concentrations of progesterone in the 36- to 45-day time periods; prolactin and relaxin concentrations were not significantly affected during or after treatment compared with administration of placebo. The results suggest a tendency towards deficient luteal function in the short-cycle GSD bitches previously studied, which in pregnancy may reflect the observed decreased prolactin concentrations; the possibility that GSD relaxin secretion is deficiency required needs further study. As oral treatment with MPA did not affect progesterone and prolactin release, it may be useful for studying luteal function in pregnant bitches with suspected hypoluteoidism. [source]

    Relationship between Taq1 A dopamine D2 receptor (DRD2) polymorphism and prolactin response to bromperidol

    AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 3 2001
    Kazuo Mihara
    Abstract The dopamine D2 receptor (DRD2) gene has a Taq1 A restriction fragment length polymorphism yielding two alleles, A1 and A2. We have previously shown that female patients with the A1 allele show greater prolactin response to nemonapride, a selective antagonist for D2-like dopamine receptors, in schizophrenic patients. In the present study, the relationship between this polymorphism and prolactin response to bromperidol was investigated in 32 untreated schizophrenic inpatients (16 males, 16 females). The daily dose of bromperidol was fixed at 6 (n,=,10), 12 (n,=,13), or 18 mg (n,=,9) during a 2-week treatment period. Taq1 A genotypes were determined by PCR method. Plasma prolactin concentration was measured by radioimmunoassay. Plasma concentration of bromperidol was measured by HPLC method. The subjects were divided into four subgroups by gender and the genotypes, i.e., 10 males and 11 females with the A1 allele, 6 males and 5 females with no A1 allele. The females with the A1 allele had the highest , prolactin (the change from the pretreatment concentration)/bromperidol concentration ratio among the other groups (P,<,0.05). The present study thus suggests that female patients with the A1 allele show greater prolactin response to bromperidol, who may have a high risk for adverse effects associated with neuroleptic-induced hyperprolactinemia. © 2001 Wiley-Liss, Inc. [source]

    Comparison of clozapine and haloperidol on some autonomic and psychomotor functions, and on serum prolactin concentration, in healthy subjects

    BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 3 2001
    J. L. Pretorius
    Aims To compare the autonomic, neuroendocrine and psychomotor effects of single doses of the ,atypical' antipsychotic clozapine and the ,classical' antipsychotic haloperidol, in healthy male volunteers. Methods Clozapine (50 mg), haloperidol (3 mg) and placebo were administered to 12 healthy male volunteers at weekly intervals, according to a balanced double-blind design. Resting pupil diameter, salivary output, heart rate, blood pressure, plasma prolactin concentration, critical flicker fusion frequency and subjective ,alertness', ,contentedness' and ,anxiety' were measured at baseline and 2, 3, 4 and 5 h after drug ingestion. Data were analysed by analysis of variance with individual comparisons (Dunnett's test) with a significance criterion of P < 0.05. Results Significant treatment effects (difference from placebo [mean, 95% CI] 5 h after drug ingestion) were as follows: clozapine reduced pupil diameter (mm; ,3.02 [,3.56, ,2.47]), salivary output (g; ,0.34 [,0.60, ,0.08]), mean arterial blood pressure (mm Hg; ,8.7 [,14.3, ,3.1]), critical flicker fusion frequency (Hz; ,3.26 [,3.94, ,2.58]), and subjectively-rated ,alertness' (mm; ,20.94 [,29.21, ,12.67]) and ,contentedness' (mm; ,12.98 [,17.90, ,8.06]), whereas haloperidol increased prolactin concentration (mU l,1; 301.3 [196.7, 405.8]) and caused small reductions in pupil diameter (mm; ,0.68 [,1.23, ,0.14]), mean arterial blood pressure (mm Hg; ,7.0 [,12.6, ,1.4]) and critical flicker fusion frequency (Hz; ,1.15 [,1.83, ,0.47]). Conclusions The effects of the antipsychotics are in agreement with their receptor binding profiles: ,1 -adrenoceptor blockade by clozapine may contribute to reductions in pupil diameter, salivation, mean arterial blood pressure and sedation, and muscarinic cholinoceptor blockade by the drug may underlie the reduction in salivation. Conversely, D2 dopamine receptor blockade by haloperidol is likely to be responsible for the increase in prolactin secretion evoked by the drug. [source]

    Comparison of Selected Endocrine Parameters During Luteal Phase and Pregnancy in German Shepherd Dogs and Beagles

    REPRODUCTION IN DOMESTIC ANIMALS, Issue 2009
    AR Günzel-Apel
    Contents Concentrations of progesterone, prolactin and relaxin in serum at predetermined intervals after ovulation (day 0) in non-pregnant and pregnant normocyclic Beagles were assayed and results compared with those observed in German Shepherd dogs (GSD) in a previous study. The goal was to determine possible reproductive hormone specificities related to the GSD breed. Furthermore, the effects of medroxyprogesterone acetate (MPA)-treatment in non-pregnant Beagles and of progesterone supplementation in pregnant Beagles on the hormone concentrations were examined. Mean concentrations of progesterone and prolactin were not different in the non-pregnant Beagles compared with those seen in non-pregnant GSD, except at days 50,60, when progesterone concentrations were found to be higher in Beagles (p < 0.05). Mean progesterone concentrations in pregnant Beagles at days 50,60 after ovulation (day 0) were higher (p < 0.05) than in GSD at that time, but not at earlier time periods. Prolactin concentrations were higher (p < 0.05) in Beagles throughout pregnancy compared with those in the GSD. Mean relaxin concentrations were numerically but not significantly lower in GSD than in Beagles throughout pregnancy. A 10-day oral MPA treatment did not affect progesterone or prolactin secretion in normocyclic non-pregnant Beagles. Medroxyprogesterone acetate serum concentrations were approximately 3.9 ng/ml during treatment and decreased to 0.42 and 0.021 ng/ml within 5 and 15 days after end of treatment, respectively. Intramuscular progesterone supplementation from days 30 to 40 in pregnant Beagles resulted in higher concentrations of progesterone in the 36- to 45-day time periods; prolactin and relaxin concentrations were not significantly affected during or after treatment compared with administration of placebo. The results suggest a tendency towards deficient luteal function in the short-cycle GSD bitches previously studied, which in pregnancy may reflect the observed decreased prolactin concentrations; the possibility that GSD relaxin secretion is deficiency required needs further study. As oral treatment with MPA did not affect progesterone and prolactin release, it may be useful for studying luteal function in pregnant bitches with suspected hypoluteoidism. [source]

    Secretion of Prolactin and Growth Hormone in Relation to Ovarian Activity in the Dog

    REPRODUCTION IN DOMESTIC ANIMALS, Issue 3-4 2001
    HS Kooistra
    In pregnant bitches an apparent increase in plasma prolactin concentrations is observed during the second half of pregnancy, mean plasma prolactin concentrations peak on the day of parturition, fall for the next 24,48 h and then rise again. During lactation, high plasma prolactin concentrations are observed. Plasma prolactin levels in non-pregnant bitches appear to be lower than in pregnant animals, particularly in the last part of the luteal phase. Pulsatile secretion of prolactin has been observed during the luteal phase and mid-anoestrus. Progression of the luteal phase is found to be associated with an increase in prolactin release. The association of a strong increase of prolactin release and a decrease of plasma progesterone concentrations has also been demonstrated in overtly pseudopregnant bitches. Elevated prolactin secretion during progression of the luteal phase in the bitch may play a role in mammogenesis and is important because of the luteotrophic action of prolactin. Acromegaly is a syndrome of tissue overgrowth and insulin resistance due to excessive growth hormone (GH) production. In the bitch, acromegaly can be induced either by endogenous progesterone or by exogenous progestagens. Progestagen-induced GH production in this species originates from foci of hyperplastic ductular epithelium of the mammary gland. Pulsatile secretion of GH has been observed in normal cyclic bitches. In contrast with the pulsatile GH secretion seen in healthy dogs, the progestagen-induced plasma GH levels in bitches with acromegaly do not have a pulsatile secretion pattern. Just as with prolactin, the plasma progesterone levels influence the secretion pattern of GH in the bitch. The pulsatile secretion pattern of GH changes during the progression of the luteal phase in healthy cyclic bitches, with higher basal GH secretion and less GH being secreted in pulses during the first part of the luteal phase. The progesterone-induced GH production may promote the proliferation and differentiation of mammary gland tissue during the luteal phase of the bitch by local autocrine/paracrine effects and may exert endocrine effects. [source]