Search results for " testosterone"
showing 9 items of 39 documents
Cardiac autonomic function reveals adaptation to military training
2011
Abstract The last 4 weeks of basic military training are very stressful. We tested the hypothesis that changes in cardiac autonomic function during this period are associated with changes in maximal oxygen uptake and/or serum hormonal concentrations in male conscripts (n=22). Cardiac vagal autonomic function was assessed by measuring the high-frequency (0.15–0.4 Hz) spectral power of R–R intervals. Maximal oxygen uptake ([Vdot]O2max) and basal serum testosterone concentration were measured at the beginning and end of the period. Individual changes in vagally mediated high-frequency power (range −15% to +25%) correlated (r=0.73, P=0.001) with changes in [Vdot]O2max (range −9% to +6%) and cha…
Different hormonal response to continuous and intermittent exercise in middle-distance and marathon runners
2008
In order to study the effects of different athletic backgrounds on exercise-induced hormonal responses, serum testosterone, luteinizing hormone, follicle-stimulating hormone and cortisol concentrations were measured before and after intensive continuous and intermittent running in well-trained middle-distance runners (MID) and marathon runners (MAR). They performed two 40-min exercises on a treadmill: a continuous run at an intensity of 80% [tempo run (TR)] and an intermittent run (IR) at an intensity of 100% of the velocity associated with VO(2max). The testosterone response to IR and the cortisol response to TR was higher (P<0.05) in MID compared with MAR. The testosterone response to IR …
Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks
2005
Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick.To test the effect of maternal yolk androgens on the chick's immune function, we experimentally manipulated, in a field study, yolk androgen levels within the physiological range by in ovo injection of either a…
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…
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…
Decreased prevalence of left-handedness among females with male co-twins: Evidence suggesting prenatal testosterone transfer in humans?
2010
Studies of singletons suggest that right-handed individuals may have higher levels of testosterone than do left-handed individuals. Prenatal testosterone levels are hypothesised to be especially related to handedness formation. In humans, female members from opposite-sex twin pairs may experience elevated level of prenatal exposure to testosterone in their intrauterine environment shared with a male. We tested for differences in rates of left-handedness/right-handedness in female twins from same-sex and opposite-sex twin pairs. Our sample consisted of 4736 subjects, about 70% of all Finnish twins born in 1983–1987, with information on measured pregnancy and birth related factors. Circulatin…
SEXUALHORMONE-BINDING GLOBULINE (SHBG) AND FREE TESTOSTERONE (FTE) IN PATIENTS WITH ULLRICH TURNLR SYNDROME(UTS) RECEIVING OXANDROLONE
1993
Our investigation showed that the concentration of SHBG decreased in healthy girls and boys at increased FIE concentrations. It was therefore the aim of the present study to examine the effects of anabolic steroid oxandrolone in SHBG and FTE concentrations in patients with Turner's syndrome. The normal dose to promote growth in patients wilh UTS is 0,1 mg/kg/BW. Our patients received a very low dose of 1,25 mg oxandrolone/doy. We analysed 21 sera of UTS patients. The determination of SHBG concentrations was performed with the IRMA (Famos diagnostics, Oulunsala, Finnland), the concentration of FTE was determined with the RIA (Immunchem.Corporation, Carson, USA). In 7 untreated UIS patients w…
The Interplay between Magnesium and Testosterone in Modulating Physical Function in Men
2014
The role of nutritional status as determinant of successful aging is very well recognized. There is recent evidence that nutrition may exert its beneficial effects through the modulation of the hormonal anabolic milieu. Under-nutrition and anabolic hormonal deficiency frequently coexist in older individuals determining an increased risk of mobility impairment and adverse outcomes. Mineral dietary assessment has received attention as key component of the nutritional modulation of anabolic status and physical performance. There is evidence that several minerals, including magnesium, exert a positive influence on Insulin-like Growth Factor-1 (IGF-1) secretion in both sexes, and Testosterone (T…
Post-encoding stress does not enhance memory consolidation: The role of cortisol and testosterone reactivity
2020
In contrast to the large body of research on the effects of stress-induced cortisol on memory consolidation in young people, far less attention has been devoted to understanding the effects of stress-induced testosterone on this memory phase. This study examined the psychobiological (i.e., anxiety, cortisol, and testosterone) response to the Maastricht Acute Stress Test and its impact on free recall and recognition for emotional and neutral material. Thirty-seven healthy young men and women were exposed to a stress (MAST) or control task post-encoding, and 24 h later, they had to recall the material previously learned. Results indicated that the MAST increased anxiety and cortisol levels, b…