Cimetidine-induced prolactin release in rats The effect of sex and gonadal steroids

1987 ◽  
Vol 114 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Hajime Watanobe ◽  
Kazuo Takebe
Keyword(s):  
Anterior Pituitary ◽  
Male Rats ◽  
Minor Role ◽  
Adult Males ◽  
Adult Age ◽  
Significant Difference ◽  
Males And Females ◽  
Plasma Prl ◽  
A Minor

Abstract. The cimetidine-induced plasma Prl response was examined in rats of both sexes. First, 10 week old intact adult males and females (dioestrous) were compared. There was no significant difference in the Prl response to cimetidine between the two groups, despite the fact that in adult females the anterior pituitary Prl content was 4 times greater than in males. Second, the effect of gonadal state in adult age on the Prl response to cimetidine was examined in both sexes. In male rats, gonadectomy at the age of 6 weeks significantly reduced the plasma Prl response as well as the pituitary Prl content, both of which were sufficiently restored by testosterone replacement. However, in females, neither gonadectomy at the age of 6 weeks nor subsequent oestradiol replacement affected the Prl response to cimetidine, despite the fact that gonadectomy significantly reduced and oestradiol treatment significantly enhanced the pituitary Prl content. Third, possible permanent effects of the postnatal gonadal milieu on the cimetidine-induced Prl response and the pituitary Prl content were examined in both sexes by castration at varying postnatal ages. The ratio of plasma Prl response to pituitary Prl content was similar in all castrated males. In females, however, the ratio decreased with increasing castration age. In conclusion, the mechanism of cimetidine-induced Prl release is less sex-dependent than are the mechanisms of Prl release by other Prl secretagogues. First, this may be due to a minor role of oestrogen in females in determining the Prl response to cimetidine. Second, the postnatal ovarian secretions may exert a permanent inhibition of the development of the cimetidine-mobilized anterior pituitary Prl pool.

Effect of histamine on the secretion of pro-opiomelanocortin derived peptides in rats

1988 ◽  
Vol 119 (2) ◽  
pp. 312-319 ◽  
Author(s):  
Ulrich Knigge ◽  
Flemming W. Bach ◽  
Steen Matzen ◽  
Peter Bang ◽  
Jørgen Warberg
Keyword(s):  
Receptor Antagonist ◽  
Anterior Pituitary ◽  
Plasma Concentrations ◽  
Gel Filtration ◽  
Male Rats ◽  
Minor Role ◽  
Plasma Acth ◽  
Intracerebroventricular Infusion ◽  
A Minor ◽  
Two Peaks

Abstract. In conscious male rats intracerebroventricular infusion of histamine increased the plasma concentrations of ACTH and β-endorphin immunoreactivity 2.5-fold (P < 0.01). Gel filtration of plasma revealed two peaks of β-endorphin immunoreactivity corresponding to β-endorphin and β-lipotropin. The two fractions increased almost equally in histamine-stimulated animals, whereas most of the circulating β-endorphin immunoreactivity in control animals corresponded to β-endorphin. Central infusion of the H1-receptor agonist 2-thiazolylethylamine and of the H2-receptor agonists dimaprit or 4-methylhistamine increased the plasma ACTH and β-endorphin immunoreactivity concentrations 2- and 3-fold, respectively (P < 0.01). Infused intracerebroventricularly, the H2-receptor antagonists cimetidine or ranitidine prevented the histamine-induced increase in plasma ACTH and β-endorphin immunoreactivity (P < 0.01), whereas the H1-receptor antagonist mepyramine inhibited the peptide responses by 70% (P < 0.01). Infused intra-arterially cimetidine or ranitidine inhibited the histamine-induced increase in plasma ACTH by 80% (P < 0.01) and plasma β-endorphin immunoreactivity by 45% (P < 0.05), whereas mepyramine or the other H1-receptor antagonist SKF-93944 inhibited the ACTH response by 50% (P < 0.05), but had no effect on the β-endorphin immunoreactivity. The results indicate that histamine increases the release of the pro-opiomelanocortin derived peptides ACTH, β-lipotropin and β-endorphin from the anterior pituitary lobe, whereas an effect of histamine on the release of β-endorphin from the neurointermediate lobe is possible. The effect of histamine seems primarily mediated by H2-receptors, whereas H 1-receptors appear to play a minor role.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

2019 ◽  
Vol 12 (4) ◽  
pp. 311-323 ◽  
Author(s):  
Salvatore Benvenga ◽  
Antonio Micali ◽  
Giovanni Pallio ◽  
Roberto Vita ◽  
Consuelo Malta ◽  
...  
Keyword(s):  
Structural Changes ◽  
Natural Antioxidants ◽  
Minor Role ◽  
Positive Role ◽  
Testosterone Levels ◽  
Tnf Α ◽  
Testicular Lesions ◽  
A Minor ◽  
Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

scholarly journals Tcf4 Is Involved in Subset Specification of Mesodiencephalic Dopaminergic Neurons

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 317
Author(s):  
Simone Mesman ◽  
Iris Wever ◽  
Marten P. Smidt
Keyword(s):  
Neuronal Differentiation ◽  
Dopaminergic Neurons ◽  
Neuronal Development ◽  
Neuronal Population ◽  
Minor Role ◽  
Initial Increase ◽  
E Box ◽  
A Minor ◽  
Bhlh Factor

During development, mesodiencephalic dopaminergic (mdDA) neurons form into different molecular subsets. Knowledge of which factors contribute to the specification of these subsets is currently insufficient. In this study, we examined the role of Tcf4, a member of the E-box protein family, in mdDA neuronal development and subset specification. We show that Tcf4 is expressed throughout development, but is no longer detected in adult midbrain. Deletion of Tcf4 results in an initial increase in TH-expressing neurons at E11.5, but this normalizes at later embryonic stages. However, the caudal subset marker Nxph3 and rostral subset marker Ahd2 are affected at E14.5, indicating that Tcf4 is involved in correct differentiation of mdDA neuronal subsets. At P0, expression of these markers partially recovers, whereas expression of Th transcript and TH protein appears to be affected in lateral parts of the mdDA neuronal population. The initial increase in TH-expressing cells and delay in subset specification could be due to the increase in expression of the bHLH factor Ascl1, known for its role in mdDA neuronal differentiation, upon loss of Tcf4. Taken together, our data identified a minor role for Tcf4 in mdDA neuronal development and subset specification.

The role of heredity in cancer.

1989 ◽  
Vol 7 (4) ◽  
pp. 527-540 ◽  
Author(s):  
E G Levine ◽  
R A King ◽  
C D Bloomfield
Keyword(s):  
Molecular Mechanisms ◽  
Familial Cancer ◽  
Tumor Development ◽  
Future Research ◽  
Minor Role ◽  
Research Activity ◽  
Environmental Interactions ◽  
Future Research Directions ◽  
A Minor

Heredity is generally felt to play a minor role in the development of cancer. This review critically examines this assumption. Topics discussed include evidence for heritable predisposition in animals and humans; the potential importance of genetic-environmental interactions; approaches that are being used to successfully locate genes responsible for heritable predisposition; comparability of genetic findings among heritable and corresponding sporadic malignancies; and future research directions. Breast, colon, and lung cancer are used to exemplify clinical and research activity in familial cancer; clinical phenotypes, segregation and linkage analyses, models for environmental interactions with inherited traits, and molecular mechanisms of tumor development are discussed. We conclude that the contribution of heredity to the cancer burden is greater than generally accepted, and that study of heritable predisposition will continue to reveal carcinogenic mechanisms important to the development of all cancers.

The Victim – a Great Actor in a Minor Role? – A Comparative Perspective

2021 ◽  
Vol 11 (1) ◽  
pp. 112-128
Author(s):  
Łukasz Duśko ◽  
Mateusz Szurman
Keyword(s):  
Social Order ◽  
American English ◽  
Active Role ◽  
Criminal Court ◽  
Minor Role ◽  
Criminal Proceedings ◽  
The One ◽  
A Minor ◽  
To Receive

Recently, the role of the victim in criminal proceedings became more significant. An observation was made that the legal interests of the victim are much more severely affected by the crime than the collective legal interests in the form of public or social order. However, the differences in the rights the victim is vested with differ substantively between particular countries. The authors present the position of the victim in American, English and French law. The solutions provided for in these systems are confronted with legal regulations adopted in Poland, i.e. the home country of the authors. It shows, surprisingly, that the role of the victim in criminal proceedings has evolved somehow independently of the implementation of the concept of restitution. On the one hand, there are legal systems in which the criminal court may order the offender to pay compensation for the damage caused, but the role of the victim still remains marginal. On the other hand, there are systems in which the victim is not only entitled to receive restitution, but he or she also has significant powers which enable him or her to play an active role in the criminal proceedings.

scholarly journals Teacher Discrimination Reduces School Performance of African American Youth: Role of Gender

2018 ◽  
Vol 8 (10) ◽  
pp. 183 ◽  
Author(s):  
Shervin Assari ◽  
Cleopatra Howard Caldwell
Keyword(s):  
African American ◽  
School Performance ◽  
African American Youth ◽  
National Sample ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Grade Point ◽  
Significant Difference ◽  
Males And Females

Background: Gender may alter African Americans’ vulnerability to discrimination. The type of outcomes that follow exposure to discrimination may also be gender-specific. Although teacher discrimination is known to deteriorate school performance, it is yet unknown whether male and female African American youth differ in the effect of teacher discrimination on school performance. Objective: This cross-sectional study explored the moderating role of gender on the effect of teacher discrimination on school performance in a national sample of African American youth. Methods: The National Survey of American Life-Adolescent Supplement (NSAL-A) enrolled a nationally representative sample (n = 810) of 13–17-year-old African American youth. Demographic factors, socioeconomic status, teacher discrimination, and school performance (grade point average, GPA) were measured. Linear multivariable regression models were applied for data analysis. Results: Males and females reported similar levels of perceived teacher discrimination. In the pooled sample, higher teacher discrimination was associated with lower school performance among African American youth (b = −0.35; 95% confidence interval (CI) = −0.49 to −0.22). Gender interacted with perceived teacher discrimination (b = 12; 95% CI = 0.24–2.02), suggesting a significant difference between males and females in the magnitude of the association between perceived teacher discrimination and GPA. In stratified models, perceived teacher discrimination was associated with worse school performance of females (b = −12; 95% CI = −0.03 to −2.78) but not males (b = 0.01; 95% CI = −0.07 to 0.08). Conclusion: In line with previous studies, gender was found to alter the vulnerability of African American youth to perceived discrimination. African American boys and girls may differ in their sensitivity to the effects of teacher discrimination on school performance.

scholarly journals Aldehyde dehydrogenase is essential for both adult and larval ethanol resistance in Drosophila melanogaster

2006 ◽  
Vol 87 (2) ◽  
pp. 87-92 ◽  
Author(s):  
JAMES D. FRY ◽  
MOLLY SAWEIKIS
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Ethanol Metabolism ◽  
Minor Role ◽  
Ethanol Sensitivity ◽  
Fruit Breeding ◽  
Structural Locus ◽  
Ethanol Resistance ◽  
A Minor

The enzyme aldehyde dehydrogenase (ALDH) is essential for ethanol metabolism in mammals, converting the highly toxic intermediate acetaldehyde to acetate. The role of ALDH in Drosophila has been debated, with some authors arguing that, at least in larvae, acetaldehyde detoxification is carried out mainly by alcohol dehydrogenase (ADH), the enzyme responsible for converting ethanol to acetaldehyde. Here, we report the creation and characterization of four null mutants of Aldh, the putative structural locus for ALDH. Aldh null larvae and adults are poisoned by ethanol concentrations easily tolerated by wild-types; their ethanol sensitivity is in fact comparable to that of Adh nulls. The results refute the view that ALDH plays only a minor role in ethanol detoxification in larvae, and suggest that Aldh and Adh may be equally important players in the evolution of ethanol resistance in fruit-breeding Drosophila.

scholarly journals Effects of microbial proteinase inhibitors on the degradation of endogenous and internalized proteins by rat yolk sacs

1981 ◽  
Vol 196 (1) ◽  
pp. 41-48 ◽  
Author(s):  
S E Knowles ◽  
F J Ballard ◽  
G Livesey ◽  
K E Williams
Keyword(s):  
Bovine Serum Albumin ◽  
Cathepsin B ◽  
Proteinase Inhibitors ◽  
Cathepsin L ◽  
Minor Role ◽  
Protein Breakdown ◽  
Inhibitory Effects ◽  
Endogenous Protein ◽  
A Minor

1. The effects of leupeptin and other microbial proteinase inhibitors were measured in rat yolk sacs on the uptake and degradation of formaldehyde-denatured 125I-labelled bovine serum albumin as well as on the degradation of 3H-labelled endogenous protein. 2. Leupeptin, at concentrations between 1 and 100 micrograms/ml, inhibits the degradation of added albumin without affecting pinocytic uptake. Accordingly large amounts of undegraded albumin accumulate within the tissue. 3. Removal of leupeptin produces a rapid recovery of the capacity to degrade albumin. 4. Endogenous protein degradation is rapidly inhibited by leupeptin, but to a far lesser extent than the breakdown of albumin. However, the inhibition is only slightly reversed on removal of leupeptin. 5. Degradation of both albumin and endogenous protein in intact yolk sacs is inhibited by the microbial proteinase inhibitors in the order: leupeptin greater than antipain greater than chymostatin; elastatinal, pepstatin and bestatin are ineffective. 6. Similar results are found when albumin is incubated in yolk-sac homogenates at pH 4 with the inhibitors. 7. The marked inhibitory effects of leupeptin, antipain and chymostatin suggest that cathepsin B and possibly cathepsin L participate in the degradation of 125I-labelled albumin in yolk sacs. By comparison, the smaller inhibitory effects of the proteinase inhibitors on endogenous protein breakdown imply a minor role of lysosomal cathepsins in this process.

scholarly journals Occurrence of L1014F and L1014S mutations in insecticide resistant Culex quinquefasciatus from filariasis endemic districts of West Bengal, India

2022 ◽  
Vol 16 (1) ◽  
pp. e0010000
Author(s):  
Priyanka Rai ◽  
Dhiraj Saha
Keyword(s):  
Culex Quinquefasciatus ◽  
West Bengal ◽  
Economic Status ◽  
Minor Role ◽  
Resistance Development ◽  
Vector Population ◽  
A Minor ◽  
First Time

Introduction Lymphatic filariasis causes long term morbidity and hampers the socio-economic status. Apart from the available treatments and medication, control of vector population Culex quinquefasciatus Say through the use of chemical insecticides is a widely applied strategy. However, the unrestrained application of these insecticides over many decades has led to resistance development in the vectors. Methods In order to determine the insecticide susceptibility/resistance status of Cx. quinquefasciatus from two filariasis endemic districts of West Bengal, India, wild mosquito populations were collected and assayed against six different insecticides and presence of L1014F; L1014S kdr mutations in the voltage-gated sodium channel gene was also screened along with the use of synergists to evaluate the role of major detoxifying enzymes in resistance development. Results The collected mosquito populations showed severe resistance to insecticides and the two synergists used–PBO (piperonyl butoxide) and TPP (triphenyl phosphate), were unable to restore the susceptibility status of the vector thereupon pointing towards a minor role of metabolic enzymes. kdr mutations were present in the studied populations in varying percent with higher L1014F frequency indicating its association with the observed resistance to pyrethroids and DDT. This study reports L1014S mutation in Cx. quinquefasciatus for the first time.

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