This study was designed to determine the efficiency and rate of testosterone (T) retrograde transfer during the follicular and luteal phase of the estrous cycle in gilts (n=27). The efficiency and the rate of the retrograde transfer of T from the ovarian effluent into blood supplying the ovary were determined for the first time under in vivo conditions. Ovarian arterial blood concentration of T...

The effect of an angiotensin-converting enzyme inhibitor, lisinopril, on gonadal hormones was assessed in 20 patients with essential hypertension. A daily dose of 5 to 20 mg of lisinopril was administered for 6 mo. In male patients, the free testosterone (f-T) concentration decreased significantly (before, 13.8+/-2.4 pg/ml; after, 9.9+/-1.5 pg/ml: mean +/- SEM, p < 0.05), whereas the plasma tot...

On September 17, 2014, an advisory committee of the U.S. Food and Drug Administration (FDA) recommended changing the labeling of testosterone products to exclude use in men with age-related decreases in testosterone.1 The FDA usually follows the advice of its advisory committees. Aging adults have always been a profitable market. In recent years, testosterone patches, gels, and other topical an...

Recently, it has been concluded that measurement of the serum free testosterone level is crucial for evaluating male gonadal function. However, the extent of the decline of serum free testosterone levels with aging and the actual levels in male infertility have not yet been clearly defined. In this study, the clinical significance of serum free testosterone levels was evaluated in a total of 24...

Although sex steroids are known to modulate brain dopamine, it is still unclear how testosterone modifies locomotor behaviour controlled, at least in part, by striatal dopamine in adolescent males. Our previous work suggests that increasing testosterone during adolescence may bias midbrain neurons to synthesise more dopamine. We hypothesised that baseline and amphetamine-induced locomotion woul...

Abstract Sexual ornaments are often considered honest signals of quality because potential costs or constraints prevent their display by low-quality individuals. Testing for physiological is difficult, as this requires experimentally forcing individuals to produce and elaborate ornaments. We use approach test whether a sexually selected trait physiologically costly male superb fairy-wrens (Malu...

OBJECTIVE To determine whether testosterone levels differ in male suicide attempters versus healthy controls and to explore the associations between testosterone levels and time of blood collection, and between testosterone levels and characteristics of suicide attempts. METHOD A sample of 112 male suicide attempters was studied. Thirty-seven male blood donors were recruited as controls. RE...

OBJECTIVE To determine correlation of serum total testosterone with body mass index (BMI) and waist hip ratio (WHR) in healthy adult males. METHODS A cross sectional study was conducted on 200 nonsmoker healthy males (aged 30-50 years) university employees. They were selected by convenience sampling technique after a detailed medical history and clinical examination including BMI and Waist Hi...

Background Periodization describes an organized approach to training variation throughout a given year. For competitive athletes this typically includes and offseason, pre-season and inseason. The offseason is meant to build muscle, increase power, strength and endurance. However, the season brings on stress that can negatively impact body composition via decreasing lean body mass (LBM). One ge...

Males of many vertebrate species aggressively defend their reproductive interests by monopolizing females, and the 'challenge hypothesis' predicts that testosterone levels in reproductive contexts rise to facilitate males' competitive behaviours necessary for meeting social challenges. The hypothesis is successful in explaining patterns of testosterone secretion in many avian species, but remai...