Search results for "testosterone"

Food supplementation reveals constraints and adaptability of egg quality in the magpie Pica pica

2015

Differences in the deposition of limited maternal resources to eggs can reflect the optimal allocation to manipulate offspring phenotype, or constraints caused by maternal condition. We examined multiple maternal substances transferred to eggs in the magpie Pica pica to test the hypothesis that certain substances represent constraint and some optimal allocation. We did this by supplementary feeding magpies prior to egg-laying and then comparing the effect of food on maternal substances in conjunction with laying order relative to a control group. Certain substances such as carotenoids, immunoglobulins and avidin responded positively to food supplementation, whereas others, such as testoste…

Concurrent endurance and strength training : neuromuscular, cardiorespiratory and hormonal effects of the exercise order in previously untrained and …

2015

The aim of the present thesis was two-fold. First, to investigate physiological adaptations to concurrent endurance and strength training performed in the same session with different exercise orders (i.e. commencing training with endurance or strength, respectively; E+S vs. S+E) in previously untrained men (n=42) (study 1). Second, to examine physiological adaptations when strength training was always performed immediately after endurance running in the same session (E+S) compared to endurance training alone (E) in recreational endurance runners (n=30) (study 2). In study 1, training consisted of 2 - 3 weekly combined endurance cycling and mixed hypertrophic and maximal strength training se…

Effects of testosterone and β-glucan on immune functions in tench

2005

A hormone manipulation was performed to examine the effects of testosterone on basal and β-glucan-induced immune functions in wild-caught male and female tench Tinca tinca. Testosterone administration elevated testosterone concentration in plasma, but did not suppress lytic activity of plasma or the chemiluminescence response of blood or head kidney phagocytes in any of the three successive samples or in any of the treatment groups. Both testosterone and β-glucan administrations had a negative effect on the relative mass of the spleen, and testosterone-treated fish lost more mass than control fish. Males had a relatively larger spleen than females, but there were no gender differences in im…

The testosterone/cortisol ratio moderates the proneness to anger expression in antisocial and borderline intimate partner violence perpetrators

2015

AbstractSeveral studies have provided evidence that antisocial, borderline and narcissistic personality traits of intimate partner violence (IPV) perpetrators significantly increase proneness to violence. In addition, an imbalance between testosterone (T) and cortisol (C) levels has been observed in this population, making individuals prone to violence. We aimed to establish whether IPV perpetrators differ in personality traits, T/C ratio and anger expression from controls, and also to examine the moderating role of the T/C ratio in the relationship between personality traits and anger expression. The sample consisted of 16 IPV perpetrators and 20 controls. T/C ratio was obtained as the quo…

2018

Purpose: Few large-scale population-based studies have adequately examined the relationships between steroid hormones, health status and physical fitness. The purpose of the study was to describe the relationship of serum basal endogenous steroid hormones (testosterone, TES; empirical free testosterone, EFT; cortisol, COR) and sex hormone-binding globulin (SHBG) to body composition, cardiovascular risk factors, and physical fitness in young healthy men. Methods: Male reservists (25±4 yrs, N=846) participated in the study. Basal TES, EFT, COR and SHBG were measured in morning fasted blood. Stepwise regression analyses were used to examine associations between individual hormones to four sepa…

The Effects of Microelectrophoretically Applied Melatonin, Putative Transmitters, Thyroxine and Sex Hormones on the Electrical Activity of Pineal Cel…

1981

ABSTRACT The effects of microelectrophoretic application of melatonin, noradrenaline, acetylcholine, thyroxine, testosterone and oestrone on pineal cell electrical activity were evaluated. With the exception of acetylcholine and oestrone pineal cells showed a circadian rhythm in sensitivity to the application of the substances. It is apparent from these studies, that (1) transmitters and hormones can bring about direct changes in the firing frequency of pineal cells, (2) all pineal cells do not respond to these substances in the same way and (3) that melatonin either produced in the pineal organ or reaching the gland via the general circulation may be capable of directly influencing the cel…

In vitro effects of estradiol, testosterone, and progesterone on 5-methoxyindole content, cyclic adenosine 3',5'-monophosphate synthesis, and norepin…

1986

To examine the effects of estradiol, testosterone, or progesterone on cyclic adenosine 3',5'-monophosphate (AMP) accumulation, 5-methoxyindole levels, and norepinephrine (NE) release by the female guinea pig pineal complex, samples of the deep, intermediate, or superficial portions of the complex were incubated in vitro with varied concentrations of either hormone. Exposure for 10 minutes to physiological amounts of estradiol (10 nM) or to 100 microM NE increased significantly cyclic AMP levels to the same extent in the three pineal regions. A maximal effect on cyclic AMP accumulation was observed at 100-nM concentrations of estradiol, with a tendency to return to basal levels at 1-10 micro…

The non-aromatizable androgen dihydrotestosterone (DHT) facilitates sexual behavior in ovariectomized female rats primed with estradiol

2020

Abstract It is still unclear whether Testosterone (T) increases sexual desire through a stimulation of the androgen receptor in relevant brain regions or through its conversion to estrogens. The aim of this study was to clarify the mechanisms of T facilitation of female sexual desire by assessing the effect of a non-aromatizable androgen (Dihydrotestosterone, DHT) in a validated animal model. Ovariectomized (OVX) Long-Evans rats were treated with oil (O) + O, 10 mcg Estradiol Benzoate (EB) + O, 10 mcg EB + 500 mcg Progesterone (P), O + 500 mcg DHT or 10 mcg EB + 500 mcg DHT (n = 12 per group). EB was administered 48 h, while P and DHT 4 h, prior to 4 sexual behavioral testing sessions in bi…

Ovarian size and blood flow in women with polycystic ovary syndrome (PCOS) and their correlations with some endocrine parameters

2005

Objective: To determine how common polycystic ovarian morphology may be in women given the clinical diagnosis of polycystic ovary syndrome (PCOS) based on chronic anovulation and hyperandrogenism and whether certain hormonal factors correlate with ovarian morphology and blood flow. Design: Prospective study. Setting: Two academic endocrinology centers in Italy. Patient(s): Three hundred twenty-six women with PCOS and 50 age-matched and weight-matched ovulatory women. Intervention(s): Ultrasound assessment of ovarian morphology in patients and controls and ovarian blood flow and fasting hormone levels in a subset of 50 patients and matched controls. Main Outcome Measure(s): Ovarian morpholog…

Screening for Low Energy Availability in Male Athletes: Attempted Validation of LEAM-Q

2022

A questionnaire-based screening tool for male athletes at risk of low energy availability (LEA) could facilitate both research and clinical practice. The present options rely on proxies for LEA such screening tools for disordered eating, exercise dependence, or those validated in female athlete populations. in which the female-specific sections are excluded. To overcome these limitations and support progress in understanding LEA in males, centres in Australia, Norway, Denmark, and Sweden collaborated to develop a screening tool (LEAM-Q) based on clinical investigations of elite and sub-elite male athletes from multiple countries and ethnicities, and a variety of endurance and weight-sensiti…