Blood Testosterone Concentrations Research Articles

Decrease in testosterone blood concentrations after testicular sperm extraction for intracytoplasmic sperm injection in azoospermic men

The introduction of intracytoplasmic sperm injection (ICSI) in 1992,1 has allowed azoospermic men to father their own children2 through testicular sperm extraction (TESE) by surgery to retrieve the spermatozoa followed by ICSI. Cryopreservation of testicular tissue is also possible. The surgical procedure for the retrieval of spermatozoa, especially in patients with non-obstructive azoospermia, is frequently linked to multiple and extensive testicular biopsies in highly spermatogenically deficient testicles.

Regulation of melatonin receptors in the pars tuberalis of Syrian hamsters transferred from long to short photoperiod: implication of melatonin and testosterone.

The exposure of long day seasonal breeders to a short photoperiod (SP) induces both sexual quiescence and a decrease in pars tuberalis (PT) melatonin receptor density. Therefore, we studied the respective roles of melatonin and testosterone on the regulation of PT melatonin receptors in Syrian hamsters transferred from long photoperiod (LP) to SP. Compared with intact sexually active animals in LP, the density of melatonin receptors was not affected by the absence of melatonin after removal of the pineal gland from animals kept in either SP or LP. In contrast, the presence of a long melatonin peak in the blood which induces gonadal atrophy induced a significant decrease in binding capacity. The SP-induced decrease in PT melatonin receptor density was also observed in castrated animals showing that it was directly regulated by melatonin, independently of circulating testosterone concentrations. However, the absence of testosterone induced an increased binding in LP, while increasing blood testosterone concentration after implantation of one testosterone-filled silastic tube resulted in a decrease in binding both in LP-and in SP-animals. These results indicate that testosterone induces a photoperiod-independent decrease in PT melatonin receptor density. In summary, these results show that both melatonin and testosterone have negative regulatory effects on the density of PT melatonin receptors.

Exercise-induced hormone responses in girls at different stages of sexual maturation.

The dependence of exercise-induced hormone responses on sexual maturation was tested in a 3-year longitudinal experiment on 34 girls (aged 11-12 years at the beginning). Sexual maturation was evaluated by Tanners five-stage scale. Children cycled for 20-min at 60% maximal oxygen uptake once a year. Cortisol, insulin, growth hormone, beta-oestradiol, progesterone and testosterone concentrations in venous blood were determined by radioimmunoassay procedures. Basal concentrations of growth hormone increased and of cortisol decreased when breast stage III was reached. Reaching breast stage IV was associated with an increase in basal concentrations of beta-oestradiol, progesterone and testosterone. The exercise induced significant increases in concentrations of cortisol, growth hormone and beta-oestradiol and a decrease in insulin concentration. At breast stage III the increase in cortisol concentration was to a lower level [467 (SEM 42) vs 567 (SEM 46)nmol x l(-1)] and growth hormone concentration to a higher level [29.4 (SEM 0.5) vs 12.8 (SEM 0.4)ng x ml(-1)], while the fall in insulin concentration was less pronounced [postexercise level 10.6 (SEM 0.9) vs 7.8 (SEM 0.8)mU x l(-1)] than in stage II. The magnitude of the cortisol response was reduced in the last stage of breast development (+42.1% vs +55.5% at stage II, +66.2% at stage III, and +50.0% at stage IV). The magnitude of beta-oestradiol response was the lowest in breast stage IV (+15.8%) and the highest at stage V (+41.1%). The progesterone response became significant at stage IV and testosterone response at stage V. In conclusion, we found that reaching breast stage III was associated with altered responses of cortisol, insulin and growth hormone concentrations while the responses of the sex hormone concentrations became pronounced in the last stages of sexual maturation.

A renin secreting ovarian steroid cell tumour associated with secondary polycythaemia.

A 67-year-old woman presented with dry skin, facial hair, hoarse voice, and weight gain. She was hypertensive (168/ 96 mm Hg), her haemoglobin concentration was 19 g/l, and haematocrit was...

Specific linkages among luteinizing hormone, follicle-stimulating hormone, and testosterone release in the peripheral blood and human spermatic vein: evidence for both positive (feed-forward) and negative (feedback) within-axis regulation.

We have investigated possible (negative) feedback and (positive) feed-forward activity within the human male gonadotropic axis by measuring serum concentrations of LH, FSH, and testosterone in blood sampled frequently and for a prolonged interval (every 20 min for 19 h) simultaneously from the peripheral circulation and the left spermatic vein. Cross-correlation analysis with time lag was used to evaluate relationships among serial serum LH, FSH, and/or testosterone concentrations over time (i.e. consistency or dissociation of trends in concentrations). Separately, Cluster analysis was applied to identify discrete LH, FSH, and testosterone pulses, which were cataloged for possible peak coincidence. The hypergeometric probability distribution was then used to test the null hypothesis that LH, FSH, and testosterone pulses are randomly associated. Cross-correlation analysis revealed: 1) peripheral blood LH and testosterone concentrations correlate positively at lags of 40-120 min with LH increases preceding testosterone increases, viz., feed-forward (P < 0.001); 2) LH and FSH concentrations in peripheral blood are positively correlated in simultaneous blood samples, as well as when FSH lags LH by 20 min (P < 0.01); 3) unexpectedly, LH and FSH concentrations in peripheral blood are inversely related at a lag of 80-100 min (P = 0.002) and 0.004, respectively) where LH lags FSH; 4) LH and testosterone concentrations in the spermatic vein show strongly positive correlations at lags of 80, 100, and 120 min (P = 0.002, 0.004, and 0.021, respectively); 5) spermatic vein testosterone concentrations correlate negatively with peripheral blood LH concentrations 20 or 40 min later (P = 0.012 and 0.05, respectively), which indicates autonegative feedback; and 6) in contrast, testosterone levels in the spermatic vein correlate negatively with FSH values in the periphery 100 and 120 min later (P < 0.01), indicating more delayed negative feedback of testosterone on serum FSH concentrations. Discrete pulse coincidence analysis disclosed: 1) a total of 30 testosterone pulses in the spermatic vein and 25 testosterone pulses in peripheral blood, with 28 LH and 29 FSH pulses in the periphery; 2) individual LH and FSH peak concordance was significantly nonrandom for FSH pulse maxima lagging LH pulse maxima by 20 min (P < 0.05 vs. randomness), with 6 observed coincidences vs. 2.9 +/- 1.5 (SD) expected; 3) peripheral LH pulses and spermatic vein testosterone pulses were strongly nonrandomly coupled at an 80-min lag, with 8 events observed vs. 3.0 +/- 1.5 events expected (P = 0.004); and 4) LH peaks in peripheral blood followed testosterone peaks in the spermatic vein by 40 min in a nonrandom manner, specifically, n = 11 observed vs. 3.0 +/- 1.5 expected (P < 0.001), indicating possible LH escape from testosterone's negative feedback. In summary, physiological regulation of the human male LH, FSH, and testosterone axis comprises multidirectional interactions, consisting of both (positive) feed-forward and (negative) feedback coupling. Based on a concept of network integration, we propose that age and other pathophysiological factors might modulate and/or disrupt these dynamic within-axis multihormonal linkages.

Testosterone and cortisol in relationship to dietary nutrients and resistance exercise.

Manipulation of resistance exercise variables (i.e., intensity, volume, and rest periods) affects the endocrine response to exercise; however, the influence of dietary nutrients on basal and exercise-induced concentrations of hormones is less understood. The present study examined the relationship between dietary nutrients and resting and exercise-induced blood concentrations of testosterone (T) and cortisol (C). Twelve men performed a bench press exercise protocol (5 sets to failure using a 10-repetitions maximum load) and a jump squat protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) with 2 min of rest between all sets. A blood sample was obtained at preexercise and 5 min postexercise for determination of serum T and C. Subjects also completed detailed dietary food records for a total of 17 days. There was a significant (P < or = 0.05) increase in postexercise T compared with preexercise values for both the bench press (7.4%) and jump squat (15.1%) protocols; however, C was not significantly different from preexercise concentrations. Significant correlations were observed between preexercise T and percent energy protein (r = -0.71), percent energy fat (r = 0.72), saturated fatty acids (g.1,000 kcal-1.day-1; r = 0.77), monounsaturated fatty acids (g.1,000 kcal-1.day-1; r = 0.79, the polyunsaturated fat-to-saturated fat ratio (r = -0.63), and the protein-to-carbohydrate ratio (r = -0.59). There were no significant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise. These data confirm that high-intensity resistance exercise results in elevated postexercise T concentrations. A more impressive finding was that dietary nutrients may be capable of modulating resting concentrations of T.

Testosterone secretion, musth behaviour and social dominance in captive male Asian elephants living near the equator.

Testosterone concentrations were measured in blood samples collected weekly over a 5 year period from six adult (19-40 year old) male Asian elephants (Elephas maximus maximus) living in captivity in Sri Lanka (7 degrees N), to investigate the relationship between androgen secretion and the occurrence of musth (temporal gland secretion, drip urination and aggressive behaviour). The testosterone profiles were very variable both within and between animals. Long-term phasic changes in blood concentrations of testosterone, associated with periods of musth, occurred in three of the six elephants, with the most pronounced cyclicity in the oldest animal. Musth occurred annually after periods of high androgen secretion and there was a positive correlation between the duration of musth and mean concentrations of testosterone during the previous 2 months. The time of musth, while consistent for an individual, was variable between animals. In four bulls living within one social group, there was a positive correlation between social rank and mean concentrations of testosterone over the 5 year study, and only the dominant animal showed periodic musth. Short-term changes in testosterone concentrations occurred in blood samples collected every 15 min for 7 h, and following the injection of 20 micrograms GnRH, consistent with regulation through the pulsatile secretion of LH. Overall, the results support the view that fully mature male Asian elephants living near the equator express an asynchronous, cyclical, circannual pattern of gonadal activity, with the cyclical pattern developing progressively from 20 to 40 years of age. The periodic increase in testosterone secretion during the gonadal cycle induces the development of musth; however, androgen withdrawal following a period of hypersecretion may be the cause of some aspects of musth behaviour (aggression, unpredictability, disobedience) which make bull elephants very difficult to manage in captivity.

The Effect of Esterification on the Release of Testosterone and Estradiol from Silicone Implants

Four experiments were conducted to determine the effect of esterification on the release of testosterone and estradiol from capsule-type silicone implants. In castrated male rats testosterone propionate and testosterone enanthate implants increased (P < .05) blood testosterone concentrations and seminal vesicle weights more than empty and testosterone implants. Testosterone propionate and testosterone enanthate implants released 4 times and 10 times, respectively, more equivalent testosterone per cm2 per day than testosterone implants. The increase in blood testosterone concentrations was proportional to the increase in implant release rate for testosterone propionate, but not for testosterone enanthate. Although estradiol- 17β implants increased (P < .05) uterine weights of ovariectomized rats, uterine weights in estradiol benzoate implanted ovariectomized rats were 1.3 times greater than in estradiol-17β implanted rats. Estradiol benzoate implants released less than 0.5 times the amount of equivalent estradiol per cm2 per day than estradiol- 17β implants.

Controlled Delivery of Testosterone Propionate Suppresses Fertility in Treated Females and Induces Prenatal Androgenization in Female Offspring Without Phenotypic Masculinization

Four experiments were conducted on the controlled delivery of testosterone propionate in cattle and sheep. Blood testosterone concentrations were more consistent across time when silicone implants were used for delivery than when compressed pellets were used for delivery. Heifers with high testosterone concentrations were infertile. Female offspring born to heifers exposed to a consistent delivery of testosterone propionate, beginning before and continuing throughout gestation, had normal female phenotype. Prenatally androgenized females were at least as fertile as untreated heifers. Combined, the four experiments demonstrate that 1) testosterone suppresses fertility of treated females, and 2) phenotypic masculinization and sterility of female offspring can be avoided when androgens are delivered prenatally by controlled release implants regardless of stage of gestation when treated.

Effects of testosterone on skeletal growth in lambs as assessed by labeling index of chondrocytes in the metacarpal bone growth plate.

The effects of testosterone on the epiphyseal growth plate of metacarpal bones of growing sheep were evaluated in 20 rams, 20 wethers, and 20 wethers receiving subcutaneous testosterone replacement therapy. Two animals from each testosterone treatment group were slaughtered at 14-d intervals from 49 to 133 d, and then at 28-d intervals until 217 d, for a total of 10 slaughter ages. Immediately after slaughter, the cannon bones were dissected of extraneous tissue, weighed, and their lengths measured. Growth plates from the metacarpal bones were isolated and explants were cultured for 24 h in medium containing [3H]thymidine. After autoradiography, labeling index was calculated as the ratio of labeled to total nuclei in the resting and proliferative zones of the growth plate. Testosterone increased (P < .03) weight and length of the metacarpal bone. Increased bone length due to testosterone was associated, in part, with a higher (P < .05) labeling index in chondrocytes of the proliferative zone of the growth plate. Labeling indices in the resting zone chondrocytes of rams were higher near the time of puberty. Accelerated growth followed by cessation of growth occurs concurrently with puberty in males of several species and is accompanied by an increase in the blood concentration of testosterone. Testosterone may mediate this accelerated growth by first increasing bone growth and then depleting the source of stem cells in the cartilage growth plate, the site where growth in length of long bones occurs.

Behavioral and Hormonal Responses of Male Song Sparrows to Estradiol-Treated Females during the Non-breeding Season

Previous studies on several species have shown that behavior of female vertebrates given estradiol implants to maintain sexual receptivity resulted in elevated levels of testosterone in males and even delayed termination of breeding in their otherwise untreated mates. However, the efficacy of such treatment in the nonbreeding season was unclear. In this study, female song sparrows, Melospiza melodia morphna, given implants of estradiol in autumn showed elevated sexual behavior—especially "chitters," a loud, female-specific vocalization used mostly during the breeding season. Males in autumn appeared to ignore the sexual behavior of these females, showed no difference in response to simulated territorial intrusion, and bad basal circulating levels of testosterone when compared with males tested in an area of control females. However, by late winter (February) males in the area where females were treated with estradiol had elevated levels of testosterone compared to control males and those of both groups sampled in autumn. These data indicate that sexual behavior of females, experimentally induced by estradiol implants, failed to increase sexual and territorial behavior in males during the autumn. On the other hand, reproductive behavior of females did appear to accelerate the vernal increase in testosterone concentrations in blood of males.

Modification of testicular cytochrome P-450 after fenitrothion administration

1. 1. The effect of fenitrothion on testicular microsomal system was analyzed and compared to the modifications induced by the drug at the hepatic level. 2. 2. Acute (165 mg/kg, 1 day) and subacute (55 mg/kg, 3 days) administration of fenitrothion caused a significant decrease on testicular cytochrome P-450 content (51 and 50% respectively) but no modification on cytochrome b 5 and NADPH cytochrome c reductase. No changes were induced by fenitrothion in testicular microsomal system after chronic treatment (5.5 mg/ml, 30 days). 3. 3. Results obtained in the liver were very similar to those observed in testis even though the percentage of cytochrome P-450 inhibition obtained after acute and subacute drug administration (45 and 43%) was smaller. 4. 4. In addition, changes in testosterone blood concentrations were also analyzed. A significant reduction of hormone plasma levels were detected at 165 and 55 mg/kg doses of fenitrothion (98% in both cases). Fenitrothion was not able to modify the levels of testosterone in the blood after chronic administration.

Plasma testosterone concentration, body weight, social dominance and scent‐marking in male marsupial sugar gliders (Petaurus breviceps; Marsupialia: Petauridae)

Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live‐trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body weight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the heaviest. In captivity this male is observed to be socially the most dominant and undertakes almost all of the scent‐marking. At least three‐quarters of each breeding season's births occur during the first month of the three‐ to four‐month season (July‐September/October), a passage of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits of high social status being immense.

Clinical, biochemical and morphologic features of acne keloidalis in a black population.

Acne keloidalis (AK) is an important cause of morbidity in Nigeria and accounts for 1.3% of patients with skin conditions in a Nigerian dermatology clinic. Treatment is usually unsatisfactory because the etiopathogenesis is unclear. A prospective clinico-pathological study was carried out to identify predisposing factors, viable treatment modalities, and prognostic indicators. The study suggested that AK is associated with the male gender seborrheic constitution, early reproductive years, and increased fasting blood testosterone concentration. Features that may predispose to the vastly predominant occipital location of the lesions include increased mast cell density and dilatation of dermal capillaries. The main aims are diagnosis of early papules and avoidance of physical and chemical traumatizing agents. Retinoic acid analogs and antiandrogens may be helpful. The widespread use of irritating physical and chemical traditional treatment remedies and delay in seeking medical attention--AK is typically asymptomatic--contribute to the relatively advanced nature of the disease at the time of presentation to the specialist.

Effects of continuous administration of gonadotropin-releasing hormone (GnRH) or a potent GnRH analogue on blood luteinizing hormone and testosterone concentrations in prepubertal bulls

The objective was to determine if continuous administration of gonadotropin-releasing hormone (GnRH) or a potent analogue (GnRH-A) for 28 or 56 d would decrease blood concentrations of luteinizing hormone (LH) and testosterone (T) in 5-month old bull calves. Treatments (5 calves/treatment), using a completely randomized design, were: control (vehicle), 3.3, 10 and 30 μg GnRH, and 3.3 and 10 μg GnRH-A (Leuprolide) per kg bodyweight/d for 28 d, administered via subcutaneously implanted mini-osmotic pumps. A second pump was implanted on day 28 in controls and bulls receiving 10 μg GnRH-A until day 56. Blood samples were taken every second day for plasma LH and T concentrations, and every 15 min for 6 hr on days 1, 14 and 27 (and days 40 and 55 where applicable) for plasma LH concentrations. There was an increase ( P<0.05) in basal plasma LH in response to GnRH and GnRH-A on day 1 (1.6, 2.1, 2.1, 2.5, 2.1 and 1.9 ng/ml for control, 3.3, 10 and 30 μg GnRH, and 3.3 and 10 μg GnRH-A, respectively; pooled s.e.d. = 0.2), but not on days 14 or 27. The number of LH pulses/6 hr was similar on day 1 for GnRH-treated and control calves, but there was a linear decrease ( P<0.05) in pulse frequency in response to GnRH doses on days 14 (1.8, 1.2, 0.6 and 0.0 for control, 3.3, 10 and 30 μg GnRH; s.e.d. = 0.5) and 27 (1.8, 1.0, 0.0 and 0.0; s.e.d. = 0.3). On days 1, 14 and 27, both GnRH-A doses suppressed ( P<0.05) LH pulsatility. GnRH (days 1–14) and GnRH-A (days 1–27) increased ( P<0.05) plasma T in a dose-dependent manner. Mean T was greater ( P<0.05) in 10 μg GnRH-A-treated than in control calves during days 29–41 (4.6 and 1.8 ng/ml; s.e.d. = 0.6) and days 43–55 (4.1 and 1.8 ng/ml; s.e.d. = 0.4). In conclusion, continuous administration of GnRH or GnRH-A to 5-month old bulls for 28 or 56 d chronically decreased LH pulse frequency, had no effect on basal LH, but increased testosterone concentrations.

Three full sister mares with a stallion-like behavior and a high blood testosterone concentration

Summary The testosterone concentration was very high in a 6-year-old maiden mare. The mare showed a typical male behavior. She appeared to have two full sisters with the same abnormal behavior. The mare's external genitalia were normal, whereas the intemai genitalia were abnormal: no cervix and no uterus, the gonads resembled a testis. The resting plasma testosterone concentration was 0.76 ng/ml. The results of the HCG stim- ulation test are shown in Table 1. The response to HCG administration was poor. Karyotyping ofS0 metaphase plates showed a normal female karyotype of 2N = 64 XX.

The hypophyseogonadal system of male rats with diabetes: an experimental study

The hypophyseogonadal system of male rats with streptozotocin-induced diabetes was studied. The hypophyseal sensitivity to LH releasing hormone was analyzed in vitro and concentrations of sex hormone nuclear receptors in the adenohypophysis, participating in gonadotropin secretion regulation according to a negative feedback mechanism, measured. Streptozotocin injection reduced blood testosterone concentration and levels of androgen nuclear receptors in the rat hypophysis. Blood LH and FSH levels in the rats with diabetes were virtually the same as in intact animals. In vitro experiments have demonstrated that diabetes development in rats did not influence the level of LH basal secretion by the hypophysis. The maximal response to LH releasing hormone was recorded in the control males in 3h incubation, whereas the rate of LH secretion in the experimental animals did not differ from the normal one. The authors suggest that changed mechanism of the hypothalamo-hypophyseo-gonadal system regulation in experimental diabetes is related to the hypophyseal disorders, involving reduction of the LH-RH-stimulated gonadotropin release and of the testosterone receptor levels, this resulting in poor reproductive function control according to the negative feedback principle.

FUNDAMENTAL AND CLINICAL STUDIES ON A NEW NONSTEROIDAL 5α-REDUCTASE INHIBITOR AND A NEW STEROIDAL ANDROGEN-RECEPTOR COMPLEX FORMATION INHIBITOR

In the case of benign prostatic hypertrophy (BPH), operative treatment presents many problems and drug therapy is still important. We have examined the effects of a new steroidal antiandrogen (TZP4238, 17α-acetoxy-6-chloro-2-oxapregna-4, 6-diene-3, 20-dione) and a nonsteroidal 5α-reductase inhibitor (ONO3805, sodium- (-) -4- [2- {2, 3-dimethyl-4- [1- (4-isobutylphenyl) ethoxy] benzoylamino} phenoxy] butyrate), which are effective in reducing prostate weight, using Wistar rats. We also examined the clinical effects of these compounds in patients with BPH. Under endogenous androgen conditions, we assessed the effects of some antiandrogens on reduced accessory sex organ weight. As a result, it was suggested that progestin drugs (TZP4238 etc.) produced this effect at low doses and that the effect lasted for more than six weeks. Under exogenous androgen conditions, that is, without central nervous system action on the prostate, the effect of ONO3805 was almost equal to that of chlormadinone acetate (CMA). Furthermore, we examined TZP4238 and other drugs in terms of on the action of androgen-receptor complex formation in the cytosol and nuclear extracts. TZP4238 showed a competitive inhibitory action, in contrast to ONO3805. On the other hand, only ONO3805 had a 5α-reductase inhibitory action. Among tested compounds neither TZP4238 nor ONO3805 significantly changed blood testosterone concentrations in the rat. Clinical results are as follows : progestin drugs (TZP4238 and CMA) were more effective than others tested in reducing prostate volume and improving voiding disturbance and residual urine volume but produced frequent loss of libido. On the other hand, the 5α-reductase inhibitor was associated with no loss of libido. To maintain the patient's quality of life, it is hoped that a drug based on 5α-reductase inhibition, which has few side effects, will be developed.

Effect of chromosomal anomalies on the plasminogen activator activity, plasminogen activator inhibition and plasmin inhibition in spermatozoa and seminal plasma 1. Chromosomal chimaerism XX/XY in the ram

In normal Friesland rams, plasminogen activator activity (PAA) and plasminogen activator inhibition (PAI) in spermatozoa and seminal plasma, plasmin inhibition (PI) in seminal plasma and testosterone concentration in blood all showed seasonal variation. In a Friesland ram with chromosomal chimaerism XX/XY, however, although PAA, PAI and PI in seminal plasma and testosterone in the blood exhibited the same seasonal variation as in normal rams, in spermatozoa the PAA and PAI showed no seasonal variation. This is the first case in which a chromosomal anomaly has been linked with abnormal patterns in PAA and PAI.

Increase in ubiquitin-immunoreactive nuclei in rat pituitary luteinizing hormone cells after castration

Immunocytochemical detection of ubiquitin in the nucleus of rat LH cells and the effects of castration and testosterone replacement on the occurrence of immunoreactive ubiquitin in the nucleus were investigated. Immunoreactive ubiquitin occurred in certain nuclei, mostly belonging to identified LH cells. The concentration of testosterone in blood was altered by castration and implantation of testosterone into castrated rats, and the occurrence of ubiquitin was examined weekly for the following 4 weeks. In castrated rats, the proportion of LH cells with ubiquitin-immunoreactive nuclei was high throughout the experiment. In castrated rats implanted with testosterone, on the contrary, the proportion remained significantly lower. Ubiquitin may be involved in the cellular activity of LH cells in the rat pituitary.