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PRL Levels (prl + level)

Distribution by Scientific Domains

Medical Sciences	71%
Life Sciences	28%

Selected Abstracts

Stimulatory and entraining effect of melatonin on tuberoinfundibular dopaminergic neuron activity and inhibition on prolactin secretion

JOURNAL OF PINEAL RESEARCH, Issue 4 2000
Yeh-Shiu Chu
The aims of the present study were to determine if melatonin exerts an effect on prolactin (PRL) secretion via the tuberoinfundibular dopaminergic (TIDA) neurons and if endogenous or exogenous melatonin has an entraining effect on the rhythmic changes of TIDA neuronal activity and PRL secretion. Melatonin given in the morning (10:00 h), dose- (0.01,1 mg/kg, ip) and time- (at 15 and 60 min, but not at 30 min) dependently stimulated TIDA neuronal activity in ovariectomized (OVX), estrogen-treated rats as determined by 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the median eminence (ME). Serum PRL was concurrently inhibited by the injection. Melatonin administered in the afternoon (15:00 h) was even more effective in stimulating the lowered TIDA neuronal activity and inhibiting the increased PRL level than that given in the morning (10:00 h). S-20098, a melatonin agonist was also effective in stimulating the TIDA neurons. In contrast, S-20928, a putative melatonin antagonist, while it had no effect by itself, blocked the effect of S-20098. Although S-20928 failed to prevent melatonin's effect on ME DOPAC levels, six interspaced injections of S-20928, from 18:00 to 01:30 h, significantly blocked the increase of ME DOPAC levels at 03:00 h, indicating that the endogenous melatonin may play a role. We further used rats that received daily injection of melatonin (1 mg/kg, ip) at 18:00 h for 10 days and found that the injection augmented basal TIDA neuronal activity at 11:00 h and blunted the afternoon PRL surge. In all, melatonin can have an inhibitory effect on PRL secretion by stimulating the TIDA neurons, and it may help to entrain the circadian rhythms of both TIDA neuronal activity and PRL secretion. [source]

Hyperprolactinaemia in 271 women: up to three decades of clinical follow-up

CLINICAL ENDOCRINOLOGY, Issue 4 2005
Katarina Berinder
Summary Objective, To characterize women with hyperprolactinaemia at diagnosis and to assess the effect of treatment after long duration of the disease. Design, Retrospective chart review. Patients and measurements, Two hundred and seventy-one women with hyperprolactinaemia at the Karolinska University Hospital, Stockholm, Sweden between 1974 and 2002 were evaluated retrospectively. Criterion for inclusion was elevated S-PRL (, 20 µg/l) found on at least two occasions. Secondary hyperprolactinaemia was excluded. The patients were followed for a median time period of 111 (6,348) months. Two hundred and forty patients were treated with dopamine agonists, 17 underwent surgery, seven received radiotherapy and seven were followed without treatment. Results, Mean age at diagnosis was 31 (± 9·5) years and median PRL level was 72 (25,3500) µg/l. Menstrual disturbances were present in 87% of the women of reproductive age and 47% had galactorrhoea. Microadenomas were found in 63%, macroadenomas in 8% and idiopathic hyperprolactinaemia in 29%. Patients with menstrual disturbances had higher PRL levels than women with normal menstrual function (P < 0·001). We found no differences in PRL levels between patients with or without galactorrhoea (P = 0·578). At the end of clinical follow-up, menstrual cycle was normalized in 94% and galactorrhoea disappeared in 94%. In the medically treated patients, median PRL levels decreased from 70 (25,3100) to 13 (0,89) µg/l, (P < 0·0001). Normalization of PRL level was achieved in 71% of the patients and 80% showed a total or partial degree of tumour shrinkage. In the surgically treated patients, 53% had normal PRL levels without medication at follow-up. Conclusion, Medical treatment was effective in correcting hypogonadism, normalizing PRL levels and reducing tumour size in the majority of the patients after short-term treatment and also in the long run. However, the possibility of transsphenoidal surgery in specific cases must be considered. [source]

Biomarker discovery in rat plasma for estrogen receptor-, action

ELECTROPHORESIS, Issue 23 2005
Tom G. Holt Dr.
Abstract To support in vivo screening efforts for estrogen receptor (ER) subtype selective therapeutic agents, we initiated work to discover surrogate markers (biomarkers) in blood plasma that would change in response to ER subtype-specific action. We used a proteomic approach employing strong anion exchange chromatography (SAX), PAGE, and MS to identify potential plasma markers for selective ER-, action. The methodology was used to compare blood from vehicle-treated rats to blood from rats treated with either 17,-estradiol (an ER-,/ER-, agonist) or compound 1 (17,-ethynyl-[3,2-c]pyrazolo-19-nor-4-androstene-17,-ol, an ER-,-selective agonist). Blood samples were first fractionated by SAX to separate fractions containing dominant common plasma proteins from fractions enriched for less-abundant plasma proteins. 1-D PAGE analysis of fractions depleted of dominant plasma proteins revealed treatment-specific changes in protein profiles. Protein bands that changed reproducibly in response to ER-, action were excised from the gel, separated by capillary LC, and identified by microspray ESI-MS. Using this method, the plasma levels of two proteins, transthyretin and apolipoprotein E, were shown to decrease in response to ER-, agonism. The method lacked the sensitivity to identify the known, 1000-fold less-abundant, estrogenic marker prolactin (PRL). However, using a commercial RIA and immunoblots, we showed that PRL levels increase significantly in response to treatment with the ER-, selective agonist, compound 1. [source]

Effect of Hyperprolactinemia in Male Patients Consulting for Sexual Dysfunction

THE JOURNAL OF SEXUAL MEDICINE, Issue 5 2007
Giovanni Corona MD
ABSTRACT Introduction., The physiological role of prolactin (PRL) in male sexual function has not been completely clarified. Aim., The aim of this study is the assessment of clinical features and of conditions associated with hyperprolactinemia in male patients consulting for sexual dysfunction. Methods., A consecutive series of 2,146 (mean age 52.2 ± 12.8 years) male patients with sexual dysfunction was studied. Main Outcome Measures., Several hormonal and biochemical parameters were studied along with validated structured interviews (ANDROTEST and the Structured Interview on Erectile Dysfunction [SIEDY]). Mild hyperprolactinemia (MHPRL; PRL levels of 420,735 mU/L or 20,35 ng/mL) and severe hyperprolactinemia (SHPRL, PRL levels >735 mU/L, 35 ng/mL) were considered. Results., MHPRL and SHPRL were found in 69 (3.3%) and in 32 (1.5%) patients, respectively. Mean age and the prevalence of gynecomastia were similar in the two groups and in subjects with normal prolactin values. MHPRL was not confirmed in almost one-half of the patients after repetitive venous sampling. Hyperprolactinemia was associated with the current use of antidepressants, antipsychotic drugs, and benzamides. SHPRL was also associated with hypoactive sexual desire (HSD), elevated thyrotropin (TSH), and hypogonadism. The association between HSD and SHPRL was confirmed after adjustment for testosterone and TSH levels, and use of psychotropic drugs (hazard ratio [HR] = 8.60[3.85,19.23]; P < 0.0001). In a 6-month follow-up of patients with SHPRL, testosterone levels and sexual desire were significantly improved by the treatment. Conclusions., Our data indicate that SHPRL, but not MHPRL, is a relevant determinant of HSD. Gynecomastia does not help in recognizing hyperprolactinemic subjects, while the use of psychotropic medications and HSD are possible markers of disease. In the case of MHPRL, repetitive venous sampling is strongly encouraged. Corona G, Mannucci E, Fisher AD, Lotti F, Ricca V, Balercia G, Petrone L, Forti G, and Maggi M. Effect of hyperprolactinemia in male patients consulting for sexual dysfunction. J Sex Med 2007;4:1485,1493. [source]