Plasma Testosterone Levels In Men Research Articles

Plasma testosterone levels in Alzheimer and Parkinson diseases

Testosterone deficiency, a treatable condition commonly seen in aging men, has been linked to Parkinson disease (PD) and Alzheimer disease (AD). In normal subjects, low testosterone levels are associated with cognitive and neuropsychiatric symptoms, yet the relationship between testosterone levels and cognitive function in PD and AD remains unclear. To examine the relationship of testosterone levels to age and cognitive function in PD and AD. Plasma testosterone levels were determined in men enrolled in a clinical registry of subjects with PD and AD, and neuropsychological testing was performed on subjects who consented. Testosterone levels in men with PD were compared with those in men with AD. In both groups, the relationship between testosterone levels and neuropsychological test scores was analyzed, adjusting for age and education. Linear regression analysis revealed that testosterone levels decreased with age in male PD patients (p < 0.03) and male AD patients (p < 0.07). The rate of decline was similar for the two groups. In PD patients, lower testosterone levels were associated with poorer performance on Trails B Seconds (p < 0.02). There is a similar age-related decline in plasma testosterone levels in men with either PD or AD. Previously described associations between low testosterone levels and frontal lobe dysfunction in normal aged men, together with these results, suggest that the hormonal deficiency may act as a "second hit" to impair cognitive function in neurodegenerative disease.

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

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 less than 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 less than 0.05). It should be noted that the percentage of peripheral CD16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of the Transient Adverse Effects of a Gonadotropin-Releasing Hormone Analogue (Buserelin) in Metastatic Prostatic Carcinoma by Administration of an Antiandrogen (Nilutamide)

Gonadotropin-releasing hormone (GnRH) analogues administered for the treatment of advanced prostatic cancer induce a transient increase in plasma testosterone levels during the first week of treatment, often with a secondary rise in plasma levels of prostatic acid phosphatase and a flareup of disease. To determine whether the antiandrogen nilutamide (Anandron) blocks these effects, we carried out a multicenter, placebo-controlled study of nilutamide in men with prostatic cancer treated with the GnRH analogue buserelin. Thirty-six men with disseminated prostatic cancer and elevated plasma levels of prostatic acid phosphatase were randomly assigned to two groups. Group 1 included 17 men who received buserelin (500 micrograms daily subcutaneously) and nilutamide (300 mg daily by mouth); group 2 included 19 men treated with buserelin and placebo. Symptoms were assessed, and plasma was collected before treatment, daily for 14 days, and on days 18, 22, and 29 after the initiation of treatment. Bone pain appeared or worsened in 5 of the 17 men in group 1 and in 12 of the 19 men in group 2 (P less than 0.05). Acute urinary obstruction occurred in one man in group 2. Despite similar changes in the plasma testosterone levels in both groups, the median concentration of plasma prostatic acid phosphatase decreased almost immediately in group 1, but increased transiently, then decreased on day 14 in group 2. Median levels of prostate-specific antigen decreased immediately in group 1 and decreased on day 8 in group 2. We conclude that nilutamide can prevent the adverse consequences of the buserelin-induced transient rise in plasma testosterone levels in men with advanced prostate cancer treated with a GnRH analogue.

EFFECT OF GLUCOCORTICOIDS ON PLASMA TESTOSTERONE IN MEN

ABSTRACT ACTH decreases plasma testosterone levels in men. The aim of this study was to assess the part played by the glucocorticoids in this effect, and the mechanism of their action. Plasma androstenedione, testosterone, cortisol and LH were measured in 8 normal men, before and after the following tests: ACTH stimulation (2 mg im), metyrapone administration (500 mg/every 4 h/6 times) and dexamethasone suppression (8 mg/day/3 days). In addition, androstenedione and testosterone were evaluated under human chorionic gonadotrophin (5000 IU HCG/day/3 days) before and after dexamethasone suppression (8 mg/day/6 days). In all patients, ACTH decreased plasma testosterone from 5.87 ± 1.59 (sd) ng/ml to 3.06 ± 0.8 (sd) ng/ml (P &lt; 0.001). In contrast, after metyrapone, the mean plasma testosterone was increased to 6.98 ± 1.75 (sd) ng/ml. This increase, though not statistically significant, was observed in all patients but one. Both tests resulted in a significant increase of plasma androstenedione (P &lt; 0.01 and P &lt; 0.001, respectively). Dexamethasone suppressed both testosterone and androstenedione levels. None of the three tests had a significant effect on the LH concentration. HCG injection increased the mean plasma testosterone to 11.46 ± 2.80 ng/ml. Dexamethasone significantly depressed (P &lt; 0.01) the testosterone response to HCG. These data are consistent with the following conclusions: 1) The decrease of plasma testosterone levels, observed in men after ACTH administration, is not observed after metyrapone induced ACTH increase. This confirms that it is related to cortisol levels rather than to ACTH itself. 2) Glucocorticoids act directly on testicular biosynthesis since they do not induce any change in LH secretion and since dexamethasone reduces testosterone response to HCG.

Plasma testosterone levels in vasectomized rats.

Department of Biological Sciences, State University of New York at Binghamton, Binghamton, New York 13901, U.S.A. (Received 25th January 1975) Conflicting reports based upon the indirect effects of vasectomy on plasma testosterone levels of the rat have recently been published. Sackler et al. (1973) reported decreased urinary ketosteroids and testicular weight after vasectomy of immature rats. Thakur et al. (1972) studied the fructose levels in the coagulating gland and maltase activity in the dorsolateral prostate gland in the mature rat after vasectomy and concluded that testosterone secretion increased. McGlynn & Erpino (1974) found no change in sexual behaviour after vasectomy and concluded that there was no change in androgen production, as did Smith (1962) who reported a normal spermatogenic cycle in the vasectomized rat and Flickinger (1972) who found that vasectomy did not alter the ultrastructure of the rat testis. Direct measurements of plasma testosterone levels in men 3 months

Depression of plasma testosterone levels in men with norethindrone

This preliminary study demonstrates the ability of norethindrone (NET) to depress plasma levels of testosterone (T) in men. A single oral dose of 25 mg of NET had no effect on the T levels despite peak plasma levels of NET of about 80 ng/ml. A daily dose of 25 mg of NET given orally for three weeks resulted in plasma levels of NET of 10–20 ng/ml when measured about 12 hours after the intake of the tablet. After four to five days of this treatment the plasma levels of T had decreased to 1–2 ng/ml, but were not further depressed below this level. After discontinuing the NET treatment, normal plasma levels of T were reached within four to five days. The daily treatment with 25 mg of NET for three weeks followed by 25 mg once a week decreased the total sperm count and increased the percentage of abnormal spermatozoa. The treatment had no effect on libido or potency.

Subcellular distribution and circadian rhythm of some glycolytic enzymes in rat testis.

The circadian variations in plasma testosterone levels in men (Saxena, Leyendercker, Chen, Gandy & Peterson, 1969) and the suggested circadian-based production of fsh and lh in birds (Murton, Bagshawe & Lofts, 1969), rats (World Health Organization, 1969) and men (Saxena et al., 1969) led us to study the circadian behaviour of two testis enzymes, hexokinase and pyruvate kinase. These enzymes, in addition to the primary rôle played in the sequence of glycolytic reactions, possess specific isoenzymes with electrophoretic and kinetic characteristics (Sosa, Altamirano, Mercado, Hernández, Reyes & Rosado, in preparation) that can be studied as part of the circadian behaviour of testis metabolism. Male albino Wistar rats, weighing 150 to 170 g, were maintained for 20 days in a

Effect of Halothane Anesthesia and of Surgery on Plasma Testosterone Levels in Men

Effect of Halothane Anesthesia and of Surgery on Plasma Testosterone Levels in Men