THE RESPONSE OF INHIBIN TO HUMAN CHORIONIC GONADOTROPHIN IS DECREASED IN SENESCENT MEN COMPARED WITH YOUNG MEN

1989 ◽  
Vol 123 (2) ◽  
pp. R9-R11 ◽  
Author(s):  
U. Fingscheidt ◽  
E. Nieschlag
Keyword(s):  
Old Age ◽  
Sertoli Cells ◽  
Young Men ◽  
Serum Testosterone ◽  
Older Men ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Before And After ◽  
Old Men ◽  
Ejaculate Parameters

ABSTRACT Inhibin and testosterone were measured in the serum of young and old men with proven fertility before and after stimulation with human chorionic gonadotrophin (hCG) in order to characterize endocrinological changes in senescence further. While there was a significant increase of both hormones in all young men, there was a decreased response of serum testosterone and an insignificant increase in inhibin in the older men. Although basal hormone levels and ejaculate parameters were not different, hCG stimulation revealed that there were decreased secretory capacities of Leydig as well as of Sertoli cells in old age.

The aging Leydig cell: VI. Response of testosterone precursors to gonadotrophin in men

1982 ◽  
Vol 100 (3) ◽  
pp. 455-461 ◽  
Author(s):  
E. P. Murono ◽  
H. R. Nankin ◽  
T. Lin ◽  
J. Osterman
Keyword(s):  
Young Adults ◽  
Leydig Cell ◽  
Young Men ◽  
Significant Rise ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Aged Population ◽  
Small Peak ◽  
Early Peak ◽  
Old Men

Abstract. The effects of a single im injection of human chorionic gonadotrophin (hCG) on circulating testosterone precursor levels at 0, 1–6, 24, 48 and 72 h were examined in normal young adults (mean age 34 years) and normal aged men (mean age 74 years). Basal 08.30–09.00 h concentrations of androstenedione and dehydroepiandrosterone were lower in aged men while progesterone levels were not significantly different from young men. A significant biphasic increase of circulating progesterone was observed in young men, characterized by an early peak at 2 h (33% above basal) and a secondary peak at 24 h (49% above basal). In old men there were no increases in circulating progesterone levels following hCG treatment during the early (1–6 h) or late (24–72 h) periods. There were not discernable increases in circulating dehydroepiandrosterone levels following hCG administration in both groups of men. Androstenedione levels in young men did not change during the first 6 h following hCG but increased significantly at 48 and 72 h, while in old men there was a small peak at 4 h (which was not statistically significant) and a secondary significant rise at 48 and 72 h. However, early and late stimulated absolute levels for androstenedione were lower in the aged population. Thus, there are differences in precursor concentrations in the basal state and in response to hCG in aged men.

scholarly journals Testosterone Response of Cryptorchid and Hypophysectomized Rats to Human Chorionic Gonadotrophin (hCG) Stimulation

1985 ◽  
Vol 38 (4) ◽  
pp. 445 ◽  
Author(s):  
Y M Hodgson ◽  
DM de Kretser
Keyword(s):  
Single Injection ◽  
Serum Testosterone ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Testosterone Levels ◽  
Hypophysectomized Rats ◽  
Secondary Rise

The testosterone responses to a single injection of HCG (100 i.u.) in hypophysectomized (hypox.), cryptorchid or sham-operated rats were followed over a 5-day period. In sham-operated rats, hCG induced a biphasic rise in serum testosterone, peaks being observed at 2 and 72 h. Reduced testis weights, elevated FSH and LH levels and reduced serum testosterone levels were found after 4 weeks of cryptorchidism, but hCG stimulation resulted in a normal 2 h peak in serum testosterone. However, the secondary rise at 72 h in cryptorchid rats was significantly lower than sham-operated rats.

EFFECT OF GLUCOCORTICOIDS ON PLASMA TESTOSTERONE IN MEN

1978 ◽  
Vol 89 (1) ◽  
pp. 126-131 ◽  
Author(s):  
G. Schaison ◽  
F. Durand ◽  
I. Mowszowicz
Keyword(s):  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Plasma Testosterone ◽  
Acth Stimulation ◽  
Testosterone Levels ◽  
Before And After ◽  
The Mean ◽  
Normal Men ◽  
Lh Secretion ◽  
Dexamethasone Suppression

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 < 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 < 0.01 and P < 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 < 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.

scholarly journals Differences in the Apparent Metabolic Clearance Rate of Testosterone in Young and Older Men with Gonadotropin Suppression Receiving Graded Doses of Testosterone

2006 ◽  
Vol 91 (11) ◽  
pp. 4669-4675 ◽  
Author(s):  
Andrea D. Coviello ◽  
Kishore Lakshman ◽  
Norman A. Mazer ◽  
Shalender Bhasin
Keyword(s):  
Lean Body Mass ◽  
Body Mass ◽  
Young Men ◽  
Serum Testosterone ◽  
Older Men ◽  
Total Testosterone ◽  
Metabolic Clearance ◽  
Clearance Rates ◽  
Testosterone Levels ◽  
Age Related

Abstract Background: Recently we found that testosterone levels are higher in older men than young men receiving exogenous testosterone. We hypothesized that older men have lower apparent testosterone metabolic clearance rates (aMCR-T) that contribute to higher testosterone levels. Objective: The objective of the study was to compare aMCR-T in older and young men and identify predictors of aMCR-T. Methods: Sixty-one younger (19–35 yr) and 60 older (59–75 yr) men were given a monthly GnRH agonist and weekly testosterone enanthate (TE) (25, 50, 125, 300, or 600 mg) for 5 months. Estimated aMCR-T was calculated from the amount of TE delivered weekly and trough serum testosterone concentrations, corrected for real-time absorption kinetics from the im testosterone depot. Results: Older men had lower total (316 ± 13 vs. 585 ± 26 ng/dl, P &lt; 0.00001) and free testosterone (4 ± 0.1 vs. 6 ± 0.3 ng/dl, P &lt; 0.00001) and higher SHBG (52 ± 3 vs. 33 ± 2 nmol/liter, P &lt; 0.00001) than younger men at baseline. Total and free testosterones increased with TE dose and were higher in older men than young men in the 125-, 300-, and 600-mg dose groups. aMCR-T was lower in older men than young men (1390 ± 69 vs. 1821 ± 102 liter/d, P = 0.006). aMCR-T correlated negatively with age (P = 0.0007), SHBG (P = 0.046), and total testosterone during treatment (P = 0.02) and percent body fat at baseline (P = 0.01) and during treatment (P = 0.004). aMCR-T correlated positively with lean body mass at baseline (P = 0.03) and during treatment (P = 0.01). In multiple regression models, significant predictors of aMCR-T included lean body mass (P = 0.008), percent fat mass (P = 0.009), and SHBG (P = 0.001). Conclusions: Higher testosterone levels in older men receiving TE were associated with an age-related decrease in apparent testosterone metabolic clearance rates. Body composition and SHBG were significant predictors of aMCR-T.

PLASMA DIHYDROTESTOSTERONE IN NORMAL ADULT MALES AND ITS RELATION TO TESTOSTERONE

1975 ◽  
Vol 79 (2) ◽  
pp. 357-365 ◽  
Author(s):  
Karl M. Pirke ◽  
Peter Doerr
Keyword(s):  
Normal Values ◽  
Control Level ◽  
Free Ligand ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Adult Males ◽  
Blood Samples ◽  
Old Men ◽  
Layer Chromatography ◽  
Close Parallelism

ABSTRACT A radioimmunoassay for dihydrotestosterone (DHT) in plasma was developed using an antiserum raised against testosterone-3-oxime-bovine-serum-albumin. After extraction of 1 ml male plasma with diethylether, DHT was separated from testosterone (T) by thin-layer chromatography. A dextran-charcoal-suspension was used for the separation of bound and free ligand. The inter-assay variability was 10.4 % (C. V.) and the detection limit 1.77 ng/100 ml. The accuracy of the method as determined by mass recoveries and the specificity were shown to be satisfactory. Normal values were obtained in 45 young to middle-aged (22–61 years) and 37 old (68–93 years) men. The median and the 95 percentiles were 20.5–51.9–76.3 (ng/100 ml) and 19.5–50.9–101.5 (ng/100 ml) respectively. While DHT did not change in old age T fell by 20.6%. DHT and T showed a significant correlation: rS = 0.426, P < 0.01 (young men), rS = 0.752, P < 0.001 (old men). After 3 daily im injections of 5000 IU human chorionic gonadotrophin (HCG), DHT increased 1.50 times (range: 1.15–2.09, n = 12), T 1.86 times (range: 1.20–2.91, n = 12). After 4 daily administrations of 40 mg fluoxymesterone DHT fell to 29.6% of the control level (range: 16.0–48.2%, n = 12). Blood samples were obtained from a 24 year old man every 15 min for 24 h. A close parallelism was observed between the concentrations of DHT and T in the plasma.

TESTICULAR FEMINIZATION

1959 ◽  
Vol XXXII (II) ◽  
pp. 222-232 ◽  
Author(s):  
D. Ikkos ◽  
K.-G. Tillinger ◽  
A. Westman
Keyword(s):  
Gonadal Dysgenesis ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Typical Case ◽  
Testicular Feminization ◽  
Intermediate Case ◽  
Histological Picture ◽  
Before And After

ABSTRACT Two cases of »testicular feminization« are described the first a typical case and the second an intermediate case between testicular feminization and gonadal dysgenesis. This second case had an unusual histological picture. A hormonal study including the estimation of urinary oestrone, 17β-oestradiol, oestriol, 17-ketosteroids and 17-hydroxy-corticosteroids before, during and after administration of human chorionic gonadotrophin was carried out in both cases, before and after bilateral gonadectomy. The results obtained indicate that in the first patient the abdominal testicles were the main source of the oestrogens found in the urine.

Miscarriage Prevention Tea Affects Plasma β-Endorphin Concentrations in Women with Early Threatened Abortions

1999 ◽  
Vol 27 (02) ◽  
pp. 277-282 ◽  
Author(s):  
Fei Sun ◽  
Dun Qing Yan ◽  
Gong Li Zhang ◽  
Jin Yu ◽  
En Nian Xiao
Keyword(s):  
Successful Treatment ◽  
Plasma Concentrations ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Psychological Consultation ◽  
Normal Ranges ◽  
Before And After ◽  
History Of ◽  
Recurrent Abortions ◽  
Gonadotrophin Releasing Hormone

Twenty threatened abortive patients in the 7-8th week of gestation were treated with a classical miscarriage prevention tea (Shou-Tai-Tang) combined with psychological consultation. All of the patients had a history of unexplained recurrent abortions. This treatment succeeded in sixteen out of 20 patients. The plasma concentrations of ß-endorphin (ß-EP), gonadotrophin releasing hormone (GnRH), human chorionic gonadotrophin (hCG), and progesterone (P4) were measured by radioimmunoassay before and after treatment. Comparied to control subjects, ß-EP levels were significantly higher, while GnRH, hCG, and P4 were lower than before treatment. Concentrations of these peptides/hormones returned to normal ranges after successful treatment.

Effect of administration of human chorionic gonadotrophin on criteria used to assess testosterone administration in athletes

1991 ◽  
Vol 131 (1) ◽  
pp. 147-154 ◽  
Author(s):  
D. A. Cowan ◽  
A. T. Kicman ◽  
C. J. Walker ◽  
M. J. Wheeler
Keyword(s):  
Serum Testosterone ◽  
International Olympic Committee ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Gas Chromatography Mass Spectrometry ◽  
Adult Males ◽  
Male Athletes ◽  
Drug Test ◽  
Testosterone Administration ◽  
Sole Criterion

ABSTRACT Abnormal ratios of testosterone to epitestosterone (T/E) and testosterone to LH (T/LH) in the urine of male athletes are indicative of testosterone administration. The T/E ratio has been adopted by the International Olympic Committee as the sole criterion used in the detection of testosterone administration. An athlete is usually considered to have failed a drug test if the urinary T/E ratio is greater than 6. Human chorionic gonadotrophin (hCG) has been used by some male athletes to stimulate testicular secretion of testosterone. The purpose of this investigation was to examine whether the urinary T/E ratio can remain unaffected by administration of hCG to normal adult males. Administration of hCG resulted in large increases in serum testosterone concentrations and urinary T/LH ratios but small changes in urinary T/E ratios of two subjects (maximum T/E values observed were 0·8 and 1·2 respectively). These observations suggest that the urinary T/LH ratio is a valuable indicator of hCG as well as of testosterone administration. This study is the first to measure urinary T/LH ratios using the technique of gas chromatography–mass spectrometry for quantification of testosterone, and highly specific monoclonal antibodies for the measurement of LH. An ultrafiltration method is proposed as part of a confirmatory procedure to be adopted in the measurement of urinary gonadotrophins for drug control in sport. Journal of Endocrinology (1991) 131, 147–154

An age-related shift in the force-frequency relationship affects quadriceps fatigability in old adults

2004 ◽  
Vol 96 (3) ◽  
pp. 1026-1032 ◽  
Author(s):  
Brian L. Allman ◽  
Charles L. Rice
Keyword(s):  
Electrical Stimulation ◽  
Relaxation Rate ◽  
Old Age ◽  
Maximum Voluntary Contraction ◽  
Young Men ◽  
Force Frequency ◽  
Leftward Shift ◽  
Age Related ◽  
Frequency Relationship ◽  
Old Men

We examined the effect of an age-related leftward shift in the force-frequency relationship on the comparative quadriceps fatigability of nine young (27 ± 1 yr old) and nine old men (78 ± 1 yr old) during low-frequency electrical stimulation. Two different protocols of intermittent trains (6 pulses on, 650 ms off) of electrical stimulation at 25% maximum voluntary contraction were performed by both groups: 1) 180 trains at 14.3 Hz [constant frequency (CF) protocol], and 2) 180 trains at the frequency corresponding to 60% of each subject's force-frequency curve [normalized frequency (NF) protocol; young 14.9 ± 0.4 vs. old 12.7 ± 0.5 Hz; P < 0.05]. The quadriceps of the old men were weaker (∼31%) and relaxation was slower compared with the young men, as assessed by the maximal relaxation rate constant of the 50-Hz tetanus (young 12.1 ± 0.2 vs. old 9.2 ± 0.5 s-1; P < 0.05) and a leftward shift in the force-frequency relationship. The NF protocol revealed a decreased fatigability in the quadriceps with old age (percentage of 1st contraction force remaining at 180th: old 63.4 ± 1.5 vs. young 58.2 ± 1.7%; P < 0.05) that was masked during the CF protocol (old 60.7 ± 1.6 vs. young 58.6 ± 2.3%; P > 0.05). Irrespective of the protocol, the maximal relaxation rate was reduced to ∼73 and ∼57% of the prefatigue value in the young and old men, respectively. The age-related leftward shift in the force-frequency relationship of the quadriceps contributed to an underestimation of the fatigue resistance with old age during the CF protocol. However, when the stimulation frequency used in the NF protocol was adjusted to account for the age-related shift in the force-frequency relationship, the quadriceps muscles of the old men were less fatigable than those of the young men. Thus we suggest that whole muscle fatigability is better examined by electrical stimulation protocols that are adjusted for inter- and intragroup differences in the force-frequency relationship.

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