THE HEMICASTRATED RAT: DEFINITION OF A MODEL FOR THE STUDY OF THE REGULATION OF TESTICULAR STEROIDOGENESIS

1982 ◽  
Vol 92 (2) ◽  
pp. 213-223 ◽  
Author(s):  
A. I. FRANKEL ◽  
W. W. WRIGHT
Keyword(s):  
Group Analysis ◽  
Age Groups ◽  
Basic Mechanism ◽  
Compensatory Hypertrophy ◽  
Significant Rise ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Testicular Steroidogenesis ◽  
Definition Of ◽  
Single Testis

A comprehensive study has been made of the hemicastrated rat from 2 to 12 months of age in order to define what might represent an ideal model in which to study testicular regulation. Although there was no compensatory hypertrophy in the remaining testis of the mature hemicastrated rat, levels of plasma testosterone fell significantly within 4 h after surgery in all age groups older than 3 months, and were restored to normal levels almost immediately, usually within 8 h. There were no significant changes in LH and prolactin, and the significant rise in FSH was sufficiently delayed (2 days or more) to suggest that none of these three hormones was implicated in any obvious way in the compensatory restoration of plasma testosterone levels. Although a single testis was capable of maintaining normal plasma testosterone concentrations, its response to human chorionic gonadotrophin at 24 h after hemicastration was significantly less than that of intact animals, suggesting that the single testis was functioning at near-maximal capacity. The hormonal responses to repetitive blood sampling and to sham-surgery simulated the response to hemicastration remarkably. However, these responses were never statistically significant in within-group analysis, and therefore did not obscure the significant fall of plasma testosterone levels in response to hemicastration. The basic mechanism by which plasma testosterone is restored in the hemicastrated rat is still unknown, but the options have been narrowed.

Effect of intraventricular injection of 5,6-dihydroxytryptamine on spermatogenesis and plasma testosterone levels in the rat

1985 ◽  
Vol 106 (3) ◽  
pp. 395-NP ◽  
Author(s):  
T. K. Das ◽  
R. Mazumder ◽  
N. M. Biswas
Keyword(s):  
Quantitative Evaluation ◽  
Wistar Rats ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Seminiferous Epithelium ◽  
Intraventricular Injection ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Testicular Steroidogenesis

ABSTRACT Quantitative evaluation of spermatogenesis at stage VII of the cycle of the seminiferous epithelium and radioimmunoassay of plasma testosterone were performed in adult Wistar rats after intraventricular injection of 5,6-dihydroxytryptamine (5,6-DHT). The rats were killed 2, 10 and 21 days after injection. Brain 5-hydroxytryptamine (5-HT) and plasma testosterone levels were found to be significantly lower in all rats treated with 5,6-DHT. A significant reduction in step 7 spermatid count was also observed after 10 and 21 days. Supplementation with human chorionic gonadotrophin for 21 days in rats injected with 5,6-DHT partially prevented the step 7 spermatid degeneration and increased testosterone levels without producing any effect on brain concentrations of 5-HT. These results suggest that changes in testicular steroidogenesis and spermatogenesis are secondary to pituitary gonadotrophin release which, in turn, is under the influence of brain 5-HT neurones. J. Endocr. (1985) 106, 395–400

INFLUENCE OF METYRAPONE ON PLASMA CONCENTRATIONS OF TESTOSTERONE AND ANDROSTENEDIONE IN MAN

1971 ◽  
Vol 68 (3) ◽  
pp. 576-584 ◽  
Author(s):  
K. O. Nilsson ◽  
B. Hökfelt
Keyword(s):  
Body Weight ◽  
Male Patient ◽  
Gradual Increase ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Basal Plasma ◽  
Normal Males ◽  
A Minor ◽  
Secondary Hypogonadism

ABSTRACT Metyrapone was administered either orally, 750 mg every four h, in a total of six doses, or intravenously 30 mg per kg body weight as a four h infusion. In three males with normal endocrine functions, metyrapone given orally or intravenously induced a fall in plasma testosterone and an elevation of androstenedione within 2–8 h. When metyrapone was administered to a patient given dexamethasone to suppress endogenous ACTH production, the androstenedione levels did not alter whereas the testosterone levels showed a slight, transient decrease. In two normal females metyrapone administration was followed by a marked increase in plasma androstenedione whereas testosterone showed only a minor, gradual increase. In one male patient with Addison's disease the basal plasma testosterone was normal whereas the level of androstenedione was low. Following metyrapone intravenously, there was a slight suppression of plasma testosterone but no change in the androstenedione concentration. In one patient with primary hypogonadism, two with secondary hypogonadism and two with Klinefelter's syndrome the plasma testosterone was low under basal conditions and did not change following metyrapone. Basal plasma androstenedione was within the range for normal males and increased markedly following metyrapone in all the cases.

Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat

1981 ◽  
Vol 96 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Mridula Chowdhury ◽  
Robert Tcholakian ◽  
Emil Steinberger
Keyword(s):  
Treated Group ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Control Group ◽  
Intact Male ◽  
Intact Control ◽  
Testosterone Levels ◽  
Oestradiol Benzoate ◽  
Direct Inhibitory Effect

Abstract. It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 μg of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.

scholarly journals Validity of the Gender Dysphoria diagnosis and incidence trends in Sweden: a nationwide register study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malin Indremo ◽  
Richard White ◽  
Thomas Frisell ◽  
Sven Cnattingius ◽  
Alkistis Skalkidou ◽  
...  
Keyword(s):  
Gender Dysphoria ◽  
Age Groups ◽  
Medical Intervention ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Incidence Trends ◽  
Interaction Terms ◽  
Definition Of ◽  
The Individual ◽  
Nationwide Register Study

AbstractThe aim of this study was to examine the validity of the Gender Dysphoria (GD) diagnoses in the Swedish National Patient Register (NPR), to discuss different register-based definitions of GD and to investigate incidence trends. We collected data on all individuals with registered GD diagnoses between 2001 and 2016 as well as data on the coverage in the NPR. We regarded gender confirming medical intervention (GCMI) as one proxy for a clinically valid diagnosis and calculated the positive predictive value (PPV) for receiving GCMI for increasing number of registered GD diagnoses. We assessed crude and coverage-adjusted time trends of GD during 2004–2015 with a Poisson regression, using assigned sex and age as interaction terms. The PPV for receiving GCMI was 68% for ≥ 1 and 79% for ≥ 4 GD-diagnoses. The incidence of GD was on average 35% higher with the definition of ≥ 1 compared to the definition of ≥ 4 diagnoses. The incidence of GD, defined as ≥ 4 diagnoses increased significantly during the study period and mostly in the age categories 10–17 and 18–30 years, even after adjusting for register coverage. We concluded that the validity of a single ICD code denoting clinical GD in the Swedish NPR can be questioned. For future research, we propose to carefully weight the advantages and disadvantages of different register-based definitions according to the individual study’s needs, the time periods involved and the age-groups under study.

scholarly journals Multilevel modelling and multiple group analysis of disparities in continuity of care and viral suppression among adolescents and youths living with HIV in Nigeria

2020 ◽  
Vol 5 (11) ◽  
pp. e003269
Author(s):  
Okikiolu Badejo ◽  
Christiana Noestlinger ◽  
Toyin Jolayemi ◽  
Juliette Adeola ◽  
Prosper Okonkwo ◽  
...  
Keyword(s):  
Young Adults ◽  
Viral Suppression ◽  
Group Analysis ◽  
Age Groups ◽  
Multilevel Modelling ◽  
Retention In Care ◽  
Healthcare Facilities ◽  
Individual Level ◽  
Multiple Group ◽  
Facility Level

IntroductionSubstantial disparities in care outcomes exist between different subgroups of adolescents and youths living with HIV (AYLHIV). Understanding variation in individual and health facility characteristics could be key to identifying targets for interventions to reduce these disparities. We modelled variation in AYLHIV retention in care and viral suppression, and quantified the extent to which individual and facility characteristics account for observed variations.MethodsWe included 1170 young adolescents (10–14 years), 3206 older adolescents (15–19 years) and 9151 young adults (20–24 years) who were initiated on antiretroviral therapy (ART) between January 2015 and December 2017 across 124 healthcare facilities in Nigeria. For each age group, we used multilevel modelling to partition observed variation of main outcomes (retention in care and viral suppression at 12 months after ART initiation) by individual (level one) and health facility (level two) characteristics. We used multiple group analysis to compare the effects of individual and facility characteristics across age groups.ResultsFacility characteristics explained most of the observed variance in retention in care in all the age groups, with smaller contributions from individual-level characteristics (14%–22.22% vs 0%–3.84%). For viral suppression, facility characteristics accounted for a higher proportion of variance in young adolescents (15.79%), but not in older adolescents (0%) and young adults (3.45%). Males were more likely to not be retained in care (adjusted OR (aOR)=1.28; p<0.001 young adults) and less likely to achieve viral suppression (aOR=0.69; p<0.05 older adolescent). Increasing facility-level viral load testing reduced the likelihood of non-retention in care, while baseline regimen TDF/3TC/EFV or NVP increased the likelihood of viral suppression.ConclusionsDifferences in characteristics of healthcare facilities accounted for observed disparities in retention in care and, to a lesser extent, disparities in viral suppression. An optimal combination of individual and health services approaches is, therefore, necessary to reduce disparities in the health and well-being of AYLHIV.

scholarly journals Review of Studies on Older Drivers’ Behavior and Stress—Methods, Results, and Outlook

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3503
Author(s):  
Yanning Zhao ◽  
Toshiyuki Yamamoto
Keyword(s):  
Age Groups ◽  
Older Drivers ◽  
Driving Simulators ◽  
Driving Experience ◽  
Older Driver ◽  
Vehicle Data ◽  
Vehicle Systems ◽  
Questionnaire Surveys ◽  
Definition Of ◽  
Short Time

This paper presents a review on relevant studies and reports related to older drivers’ behavior and stress. Questionnaires, simulators, and on-road/in-vehicle systems are used to collect driving data in most studies. In addition, research either directly compares older drivers and the other drivers or considers participants according to various age groups. Nevertheless, the definition of ‘older driver’ varies not only across studies but also across different government reports. Although questionnaire surveys are widely used to affordably obtain massive data in a short time, they lack objectivity. In contrast, biomedical information can increase the reliability of a driving stress assessment when collected in environments such as driving simulators and on-road experiments. Various studies determined that driving behavior and stress remain stable regardless of age, whereas others reported degradation of driving abilities and increased driving stress among older drivers. Instead of age, many researchers recommended considering other influencing factors, such as gender, living area, and driving experience. To mitigate bias in findings, this literature review suggests a hybrid method by applying surveys and collecting on-road/in-vehicle data.

Food intake, physical activity and quality of life among children and youth

Work ◽  
2021 ◽  
pp. 1-10
Author(s):  
Emília Martins ◽  
Rosina Fernandes ◽  
Francisco Mendes ◽  
Cátia Magalhães ◽  
Patrícia Araújo
Keyword(s):  
Quality Of Life ◽  
Physical Activity ◽  
Healthy Lifestyle ◽  
Eating Habits ◽  
Age Groups ◽  
Related Quality ◽  
Health Related ◽  
Life Habits ◽  
Definition Of

BACKGROUND: The health-related quality of life construct (QoL) implies a relationship with eating habits (EA) and physical activity (PA). Sociodemographic and anthropometric variables (gender, age and Body Mass Index - BMI) are highlighted in the definition of healthy lifestyle habits promotion strategies. OBJECTIVE: We aim to characterize and relate PA, EA and QoL in children/youth and explore gender, age and BMI influences. METHODS: It is a non-experimental study, with 337 children/youth, ages between 8 and 17 years (12.61±2.96), mostly from the rural inland of Portugal. In data collection we used a sociodemographic and anthropometric questionnaire, a weekly register table of EA and Kid-Kindl (QoL). Statistical analysis (p <  0.05) were performed in SPSS-IBM 25. RESULTS: Lower BMI was associated with better EA (p <  0.001), PA (p <  0.05) and self-esteem (p <  0.01) and worse scores on family subscale of QoL. Female showed higher fruit intake (p <  0.05). The older has shown better results. PA is positively correlated with QoL (p <  0.01) and EA (p <  0.05). CONCLUSIONS: It is important to explore other relevant social and family dimensions, to promote intervention programs with parents, school and community, as well as healthy practices policies. The intervention in these age groups is critical for a longer-term impact in improving healthy life habits.

Association Between Androgen Receptor Gene CAG Repeat Polymorphism and Plasma Testosterone Levels in Postmenopausal Women

2005 ◽  
Vol 12 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Ilma Simoni Brum ◽  
Poli Mara Spritzer ◽  
Franyoise Paris ◽  
Maria Augusta Maturana ◽  
Franyoise Audran ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Postmenopausal Women ◽  
Receptor Gene ◽  
Androgen Receptor Gene ◽  
Cag Repeat ◽  
Plasma Testosterone ◽  
Repeat Polymorphism ◽  
Testosterone Levels

Lymphocyte subset distribution and natural killer cell activity in men with idiopathic hypogonadotropic hypogonadism

1991 ◽  
Vol 124 (4) ◽  
pp. 399-404 ◽  
Author(s):  
Wieland Kiess ◽  
Linda L. Liu ◽  
Nicholas R. Hall
Keyword(s):  
Natural Killer Cell ◽  
Natural Killer ◽  
Natural Killer Cell Activity ◽  
Hypogonadotropic Hypogonadism ◽  
Killer Cell ◽  
Cell Activity ◽  
Hormonal Treatment ◽  
Plasma Testosterone ◽  
Idiopathic Hypogonadotropic Hypogonadism ◽  
Testosterone Levels

Abstract. Sex-related differences in immune responsiveness are mediated at least in part by sex steroid hormones. Lymphocyte subset distribution in peripheral blood and natural killer cell function both have been reported to be under hormonal control. In order to gain more insight into sex steroid hormone action on the immune system, we have measured the lymphocyte subset distribution and natural killer cell activity in 18 men with idiopathic hypogonadotropic hypogonadism before treatment, and after hormonal treatment had normalized plasma testosterone levels. In untreated patients, the mean plasma testosterone concentrations were significantly lower than those in the treated men (3.0 ± 0.5 nmol/l vs 16 ± 1.7 nmol/l, p < 0.001). The percentage of peripheral CD3+ lymphocytes, CD8+ cells, the CD4+/CD8+ ratio, and the natural killer cell activity of peripheral mononuclear cells measured in a 51Cr release assay against target K 562 cells did not differ between patients with idiopathic hypogonadotropic hypogonadism and healthy adults, and most importantly, did not change during hormonal treatment which normalized plasma testosterone levels in the patients. In contrast, the percentage of peripheral CD4+ cells was significantly higher in untreated patients compared with normal adult subjects or patients with idiopathic hypogonadotropic hypogonadism after hormonal treatment that resulted in normal plasma testosterone levels (53 ± 2 vs 47 ± 2, p < 0.05). It should be noted that the percentage of peripheral CD 16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls. The percentage of CD16+ cells in peripheral venous blood rose significantly after hormonal treatment restored plasma testosterone levels to normal (6 ± 1 vs 11 ± 1, p < 0.001). In addition, the percentage of peripheral CD16+ cells correlated significantly with the plasma testosterone levels measured in men with idiopathic hypogonadotropic hypogonadism (r = 0.534, p < 0.001). In conclusion, both the percentage of peripheral CD4+ cells (T-helper lymphocytes) and peripheral CD16+ cells (non-T-non-B cells) are related to the plasma testosterone levels in men with idiopathic hypogonadotropic hypogonadism. These data suggest that in vivo human immune cells are under the regulatory influence of endogenous sex steroids.

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