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Presse Medicale (Paris, France : 1983) Jun 1989
Topics: Adult; Erectile Dysfunction; Humans; Hyperprolactinemia; Male; Prolactin
PubMed: 2525753
DOI: No ID Found -
Journal of Reproduction and Fertility Jul 1989Hypoprolactinaemia was induced by bromocriptine (CB154; 100 mg/day) which decreased circulating prolactin by 40% (P less than 0.06), but did not affect conceptus...
Hypoprolactinaemia was induced by bromocriptine (CB154; 100 mg/day) which decreased circulating prolactin by 40% (P less than 0.06), but did not affect conceptus survival at Day 25 when administered on Days 10-16 when compared to saline:ethanol-treated control gilts. Bromocriptine or vehicle was administered to cyclic gilts on Days 10-11, oestradiol valerate was injected on Day 11 and uterine flushings were collected on Day 12. Total recoverable protein and uteroferrin in uterine flushings were not affected by treatment. However, leucine aminopeptidase activity (P less than 0.02) and total recoverable Ca2+, Na+, K+ and Cl- (P less than 0.05) were decreased in uterine flushings of gilts that received bromocriptine, suggesting that hypoprolactinaemia decreased general secretory activity of the endometrial epithelium and modulated ionic changes, respectively, in the uterine environment of pigs. Subcutaneous administration of pig prolactin (1 mg/12 h) increased (P less than 0.001) serum prolactin 4.5-fold. The interaction between hyperprolactinaemia and progesterone, without oestrogen, on components of uterine flushings were determined using gilts that received progesterone (200 mg/day) and prolactin or saline on Days 4-14 after ovariectomy on Day 4. On Day 15, there were no differences (P greater than 0.05) in any of the uterine secretory components measured. Hyperprolactinaemia (1 mg pig prolactin on Days 6-11) enhanced overall uterine secretory response on Day 12 to oestradiol (5 mg) administered on Day 11 compared to gilts that received 1 ml saline on Days 6-11 of the oestrous cycle. Total recoverable protein and leucine aminopeptidase activity were greater (P less than 0.05) for oestradiol-treated gilts, but effects of prolactin were not significant. Total recoverable glucose (P less than 0.01), PGF-2 alpha (P less than 0.02), uteroferrin (P less than 0.01) and specific activity of uteroferrin (P less than 0.001) were increased by prolactin and oestradiol, but not oestradiol alone. Calcium (P less than 0.05), chloride (P less than 0.05) and potassium (P less than 0.01) were increased in response to oestradiol. These results indicate an interaction between oestradiol and prolactin, but not progesterone and prolactin, which enhances secretion of some products of the pig uterine endometrium.
Topics: Animals; Endometrium; Estradiol; Female; Fetal Death; Pregnancy; Prolactin; Swine
PubMed: 2760896
DOI: 10.1530/jrf.0.0860713 -
The Journal of Endocrinology Jul 1998Formation of new capillary blood vessels, termed angiogenesis, is essential for the growth and development of tissues and underlies a variety of diseases including tumor...
Formation of new capillary blood vessels, termed angiogenesis, is essential for the growth and development of tissues and underlies a variety of diseases including tumor growth. Members of the prolactin hormonal family bind to endothelial cell receptors and have direct effects on cell proliferation, migration and tube formation. Because many angiogenic and antiangiogenic factors are produced by endothelial cells, we investigated whether endothelial cells expressed the prolactin gene. Here we show that bovine brain capillary endothelial cells (BBCEC) in culture express the full-length prolactin messenger RNA, in addition to a novel prolactin transcript, lacking the third exon of the gene. In addition cultures of BBCEC synthesize and secrete prolactin-like immunoreactive proteins with apparent molecular masses of 23, 21 and 14 kDa. The prolactin-like nature of these proteins in supported by the observation that Nb2-cells, a prolactin-responsive cell line, were stimulated to proliferate when co-cultured with endothelial cells and this stimulation was neutralized with prolactin-directed antibodies. Finally, consistent with a possible autocrine effect of endothelial-derived prolactins, polyclonal and monoclonal prolactin antibodies specifically inhibited basal and basis fibroblast growth-factor-stimulated growth of endothelial cells. Taken together, the present findings support the hypothesis of the prolactin gene being expressed in endothelial cells as proteins that could act in an autocrine fashion to regulate cell proliferation.
Topics: Animals; Antibodies, Monoclonal; Autocrine Communication; Brain; Capillaries; Cattle; Cell Division; Cell Line; Cells, Cultured; Coculture Techniques; Endothelium, Vascular; Fibroblast Growth Factor 2; Prolactin; RNA, Messenger
PubMed: 9713335
DOI: 10.1677/joe.0.1580137 -
Life Sciences 1988On an every other day basis, chronically catheterized male rats were subjected to a 30 sec grid shock in either an ascending (0.0, 0.25, 1.0, 4.0 mA) or descending...
On an every other day basis, chronically catheterized male rats were subjected to a 30 sec grid shock in either an ascending (0.0, 0.25, 1.0, 4.0 mA) or descending order. A third group was repeatedly subjected to 1.0 mA shock over the same time frame. In 85% of the shock trials, plasma prolactin increased from baseline levels, thus indicating that prolactin is a relatively reliable index of stress. However prolactin did not change in a step-wise fashion with stressor intensity for a significant number of rats. Data from the group given repeated exposure to the 1 mA stressor showed no evidence of habituation--a process which might have explained the findings. This study indicates that prolactin levels do not sensitively track stressor intensity for individual rats.
Topics: Animals; Electroshock; Male; Prolactin; Rats; Rats, Inbred Strains; Stress, Physiological
PubMed: 3367683
DOI: 10.1016/0024-3205(88)90438-9 -
Biochemistry Mar 2011Human prolactin (hPRL) binds two human prolactin receptor molecules, creating active heterotrimeric complexes. Receptors bind dissimilar hormone surfaces termed site 1...
Human prolactin (hPRL) binds two human prolactin receptor molecules, creating active heterotrimeric complexes. Receptors bind dissimilar hormone surfaces termed site 1 and site 2 in an obligate ordered process. We sought to map the functional epitopes in site 1 of hPRL. Extensive alanine mutagenesis (102 of the 199 residues) showed approximately 40% of these mutant hPRLs changed the ΔG for site 1 receptor binding. Six of these residues are within 3.5 Å of the receptor and form the site 1 functional epitopes. We identified a set of noncovalent interactions between these six residues and the receptor. We identified a second group of site 1 residues that are between 3.5 and 5 Å from the receptor where alanine mutations reduced the affinity. This second group has noncovalent interactions with other hormone residues and stabilized the topology of the functional epitopes by linking these to the body of the protein. Finally, we identified a third group of residues that are outside site 1 (>5 Å) and extend to site 2 and whose mutation to alanine significantly weakened receptor binding at site 1 of prolactin. These three groups of residues form a contiguous structural motif between sites 1 and 2 of human prolactin and may constitute structural features that functionally couple sites 1 and 2. This work identifies the residues that form the functional epitopes for site 1 of human prolactin and also identifies a set of residues that support the concept that sites 1 and 2 are functionally coupled by an allosteric mechanism.
Topics: Alanine; Binding Sites; Epitopes; Humans; Models, Molecular; Mutagenesis; Mutation; Prolactin; Protein Conformation; Surface Plasmon Resonance; Thermodynamics
PubMed: 21226500
DOI: 10.1021/bi101838s -
British Medical Journal Apr 1974Rat hearts with coronary circulations perfused by the Langendorff technique were studied. Recordings were made of the electrical and mechanical activity. Once the rate...
Rat hearts with coronary circulations perfused by the Langendorff technique were studied. Recordings were made of the electrical and mechanical activity. Once the rate and rhythm of each heart and stabilized it was perfused with Ringer-Locke solution for 90 minutes; frusemide (40 mug/ml) was added to the perfusate during the last 30 minutes of this period. Eighteen experiments were performed-six controls, six in which prolactin at a concentration of 50 ng/ml was added to the perfusate for the whole 90 minutes, and six in which a prolactin concentration of 200 ng/ml was used.With the controls heart rate and rhythm remained steady, but there was a slow decline in amplitude of the contraction. With a prolactin concentration of 50 ng/ml the heart rate rose to about 40% above control during the first hour and after an initial sharp increase the contraction amplitude declined more rapidly than in the controls. The prolactin concentration of 200 ng/ml produced a decline of about 25% in heart rate over the first hour and amplitude behaved much as in the controls. Frusemide had no clear effect on the rate of beating of the controls, but it tended to reverse both the acceleration produced by 50 ng/ml prolactin and the slowing produced by the higher dose. Both the doses of prolactin consistently caused disturbances of rhythm. These effects occur at concentration of prolactin found in human plasma in various pathophysiological conditions.
Topics: Animals; Arrhythmias, Cardiac; Electrocardiography; Electrophysiology; Furosemide; Heart; Heart Rate; In Vitro Techniques; Perfusion; Prolactin; Rats
PubMed: 4821039
DOI: 10.1136/bmj.2.5909.27 -
Journal de Gynecologie, Obstetrique Et... 1975Prolactin is a pituitary stimulating hormone which is capable of inducing and maintaining lactation. The recent introduction of very sensitive methods of estimating the...
Prolactin is a pituitary stimulating hormone which is capable of inducing and maintaining lactation. The recent introduction of very sensitive methods of estimating the levels have led to its isolation and identification of its physico-chemical characteristics in the human and also to the physio-pathological study of its secretion. The authors demonstrate a human homologous radio-immune level estimating technique which uses a human anti-prolactin serum obtained from the rabbit human prolactin highly purified with iodine 125 using the lacto-peroxydase method. This radio-immune level estimation constitutes a feasible and satisfactory approach for the base level of prolactin. The spread of results which have been obtained, however, showed that one sole estimation is not sufficient. The authors draw attention to the need to carry out dynamic tests of stimulation or of braking in order to reveal possible abnormalities of prolactin secretion.
Topics: Animals; Circadian Rhythm; Female; Humans; Iodine Radioisotopes; Male; Prolactin; Rabbits; Radioimmunoassay
PubMed: 1214038
DOI: No ID Found -
The Journal of Experimental Zoology Feb 1990To test whether growth of the winter coat in short day lengths is contingent on suppression of plasma prolactin (Prl) levels, female meadow voles (Microtus...
To test whether growth of the winter coat in short day lengths is contingent on suppression of plasma prolactin (Prl) levels, female meadow voles (Microtus pennsylvanicus) were kept in short day lengths for 12 weeks and were injected daily with saline or Prl; long-day animals were treated with either the dopamine agonist, bromocryptine (bromo), bromo plus Prl, or saline. Prl treatment prevented the growth of the winter coat normally observed after 12 weeks in short day lengths, but bromocryptine did not stimulate pelage growth in long-day voles. Pelage growth in short day lengths appears contingent upon decreased plasma prolactin levels.
Topics: Analysis of Variance; Animals; Arvicolinae; Biological Clocks; Bromocriptine; Female; Hair; Lighting; Prolactin
PubMed: 2179462
DOI: 10.1002/jez.1402530208 -
Revue Francaise de Gynecologie Et... Sep 1986Normal serum prolactin levels range from 5 to 20 ng/ml (circadian rhythm, effect of stress, relation with estrogen secretion). Neuroleptics increase serum prolactin...
Normal serum prolactin levels range from 5 to 20 ng/ml (circadian rhythm, effect of stress, relation with estrogen secretion). Neuroleptics increase serum prolactin levels. Normal concentrations are restored within 24 to 48 hours of discontinuation of the drug. When neuroleptics are given for a long period of time, serum prolactin concentrations fall gradually to low levels. There is no conclusive evidence that prolactin plays a role in breast tumors in women. Epidemiologic studies have shown that neuroleptics are not responsible for increased incidences of these tumors.
Topics: Animals; Breast Neoplasms; Female; Humans; Hyperprolactinemia; Male; Mice; Pregnancy; Prolactin; Tranquilizing Agents
PubMed: 3764300
DOI: No ID Found -
Journal de Gynecologie, Obstetrique Et... Mar 1978
Review
Topics: Animals; Breast; Caseins; Cyclic AMP; DNA; Estrogens; Female; Genetic Code; Glucocorticoids; Lactation; Mammary Glands, Animal; Placental Lactogen; Pregnancy; Progesterone; Prolactin; RNA, Messenger; Rabbits; Receptors, Cell Surface; Sheep
PubMed: 209078
DOI: No ID Found