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At least 19 recordsLinked to original sources
PubMed1977

Oestrogen content of semen and the effect of exogenous oestradiol-17beta on the oestrogen and androgen concentration in semen and blood plasma of bulls.

The concentration (mean +/- S.E.M.) of oestrogen in semen (0-89 +/- 0-04 ng/ml) of bulls was 8-9-fold higher than in blood plasma (0-10 +/- 0-01 ng/ml) while the concentration of androgen in semen (1-15 +/- 0-26 ng/ml) was 2-7-fold lower than in blood plasma (3-21 +/- 0-47 ng/ml). This concentration of oestrogen in semen was not influenced by 0,1,3 or 5 false mounts or when ejaculations occurred at 2-min intervals. When 100 mg oestradiol-17beta were injected i.v. the oestrogen level in semen followed that in the plasma.

Androgens↗
PubMed1977

Plasma androgen concentrations in diabetic women.

Plasma androgen levels were determined in women assigned to the following groups: idiopathically hirsute, diabetic, both idiopathically hirsute and diabetic, and normal. The androgens examined were androstenedione (AD), dihydrotestosterone (DHT), testosterone (T), and dehydroepiandrosterone (DHEA). We find statistical differences between young (less than 38 years) and older (larger than or equal to 38 years) controls at confidence levels of p less than or equal to 0.01 for AD, DHT, and T and of p less than or equal to 0.05 for DHEA. The results indicate that peak circulating androgen levels occur prior to age 30-35 years for women. There are no significant differences between the young controls and young idiopathically hirsute subjects, but a statistical difference exists between older hirsute and older controls for all four androgens (p less than or equal to 0.05). When a comparison is made among the diabetic, hirsute diabetic, and older control groups (all groups larger than or equal to 38 years), the diabetic group is significantly higher than the control in plasma AD (p less than or equal to 0.01) and DHEA (p less than or equal to 0.05). These same two steroids are also higher in the diabetic group than in the hirsute diabetic group (p less than or equal to 0.05), while the latter differs from controls only in testosterone levels (p less than or equal to 0.05). DHT levels are similar for all three groups.

Adult↗
PubMed1978

Androgen concentration and partial characterization of 5alpha reductase in the epididymis of the rhesus monkey.

The 5alpha reductase activity ofthe monkey epididymis was studied. The enzyme was found in particulate subcellular fractions, its distribution closely resembling that of the microsomal marker enzyme NADPH: cytochrome c reductase, suggesting an association of 5alpha reductase with membranes of the endoplasmic reticulum. Maximal enzyme activity was found at pH 5.4 and at 32--37 C. The crude nuclear preparation had a Km: 0.315 x 10(-6)M and Vmax: 168 pmoles/mg protein/h. The microsomal enzyme had a Km: 0.243 x 10(-6)M and Vmax: 828 pmoles/mg protein/h. Neither enzyme preparation was affected by addition to the incubation media of dihydrotestosterone (DHT) or 5alpha-androstane-3alpha,17beta-diol. The endogenous androgen concentration in the epididymides of 2 different monkeys, in ng/g wet weight was: DHT 20.81 +/- 1.98; T: 9.0L +/- 2.83; diol: 3.03 +/- 0.41.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1977

Sexual behavior and plasma androgen concentrations in the male eider duck (Somateria mollissima).

Eider ducks showed clear tidal and seasonal cycles of display when involved in pair-formation behaviour. Plasma androgen (testosterone and dihydrotestosterone) concentrations did not follow similar tidal cycles but there was a 4-fold increase of androgen in spring when rates of display increased 2-fold. There was no difference in androgen levels in blood samples taken from paired birds before and after coitus. Androgens therefore appear to be essential for the expression of sexual behaviour, but there is no apparent quantitative correlation between overt sexual activity and androgen concentrations.

Androgens↗
PubMed1992

Androgen concentrations in expressed prostatic secretions: no correlation with tissue levels.

In an attempt to determine whether the androgen profiles of the prostate fluid (EPS) mirror the concentrations in the prostate tissue, we have measured testosterone and dihydrotestosterone (DHT) in EPS and correlated their levels to the concentrations found in hyperplastic prostate tissue (BPH) obtained from the same 19 patients. Although androgen concentrations in EPS were very high (testosterone = 106.7 +/- 81.9 ng/g dry weight; DHT = 54.2 +/- 11.2 ng/g dry weight), they did not reflect the concentrations measured in BPH tissue (testosterone = 7.56 +/- 1.54 ng/g dry weight; DHT = 10.54 +/- 0.63 ng/g dry weight). Additionally the accumulation of tissular DHT usually associated with BPH was not mirrored in the EPS specimens which demonstrated a relatively higher concentration of testosterone when compared to DHT. In EPS, there was also a very strong correlation between testosterone and DHT concentrations (r = 0.89; P less than 0.01). We have also measured zinc concentrations in EPS and BPH tissue but were unable to detect any relationship between the two parameters. Significantly, however, EPS zinc concentrations showed a close correlation with EPS testosterone (r = 0.73; P less than 0.01) and DHT (r = 0.69; P less than 0.01) concentrations.

Body Fluids↗
PubMed1977

Androgen concentrations in prostate and serum of the male and female Praomys (Mastomys) natalensis.

The levels of androgens in the male prostate, seminal vesicles, and serum, as well as in the female prostate and serum, were measured in the rodent Praomys (Mastomys) natalensis. Measurements were made in different age groups of both males and females using a sensitive radioimmunoassay. The results showed that the values for serum testosterone were 10 times greater in the male than the female. The concentration of serum dihydrotestosterone in the male was approximately one-tenth of the concentration of testosterone. The recovery of dihydrotestosterone from the prostate in the female and seminal vesicle in the male was low and these values were not considered. The concentrations of testosterone and dihydrotestosterone in the male prostate were 8.3 +/- 0.5 and 20.0 +/- 2.4 ng per g of wet tissue, respectively. The concentration of testosterone in the female prostate, 7.1 +/- 0.5 ng per g of wet tissue, was similar to that in the male. These studies have shown that the female Mastomys has a prostate which exists in a low androgen environment; it is suggested that this could be used as an experimental model for studying hormonal effects on the prostate.

Androgens↗
PubMed1977

Androgen concentration in motor neurons of cranial nerves and spinal cord.

After injection of [3H]dihydrotestosterone, a major testosterone metabolite, radioactivity is concentrated in nuclei of certain cells in the midbrain, pons, medulla oblongata, cerebellum, and spinal cord. While there is some overlap between androgen and estrogen target neuron distribution, certain motor neurons appear to be selectively labeled by androgen; in contrast, estrogen localization prevails in sensory neurons. These results may help to explain why male sexual behavior in some rodents is not fully activated with dihydrotestosterone alone but in addition requires estradiol, a testosterone metabolite.

Adrenalectomy↗
PubMed1976

[Endocrine and sperminogenic testicular function. 7. Relationship between testicular and plasma androgen concentrations in boars of different ages].

Testicular tissue and blood samples (V. spermatica interna) were taken from 32 boars during castration. The animals were of different age groups. Against this background, comparative studies were conducted into the relationships between testicular and plasma testosterone. A very close correlation was found to exist between the androgen values in testicular tissue and those in the blood plasma of V. spermatica interna (r = 0.9795), wich appeared to support the conclusion that by determination of blood plasma the androgen content in the testes can be established with high probability.

Age Factors↗
PubMed1975

Plasma estrogen and androgen concentrations in children during adolescence.

Using Sephadex LH-20 chromatography and a radioimmunological technique, the simultaneous measurement of estrone, estradiol, testosterone and dihydrotestosterone was performed in a single extract of peripheral plasma in children. In 44 boys and 43 girls, the mean plasma concentration of estrone rose steadily in both sexes, though more pronounced in the girls. For estradiol, this increment was noted only for the girls. For testosterone, the boys showed a spurt after pubertal stage 3, whereas the girls did not show any rise throughout the developmental phases. The girls, however, showed increment in dihydrotestosterone, concentration from pubertal stage 1 to 3, and plateaued thereafter. The boys showed marked increment in the concentration of this steroid throughout development, although less pronounced as that seen for testosterone. Plasma estrogens correlated better with the clinical evaluation of sexual maturation than with chronological ages in the girls. Similarly, the boys showed better relationship between the androgens and maturational stages than with chronological age. The girls also demonstrated a steep increment in the SDs for the estrogen values with sexual maturation (at stages 3 and 4, the SDs for estrone and estradiol were 0.26 and 0.80 respectively, at stage 5 they were 0.82 and 1.49 respectively) reflecting perhaps the onset of cyclic activity. When the estrogen values were related to the androgen values, the boys demonstrated a high association (r equals 0.78). This correlation was absent in the girls.

Adolescent↗
PubMed1978

Autoradiographic localization of androgen-concentrating cells in the brain of the male domestic fowl.

Cells in the male fowl brain which accumulate radioactivity following 3H testosterone (T) administration were identified by autoradiography. Labelled cells were found principally in hypothalamic, limbic and midbrain structures. Marked uptake was observed in the preoptic area (POA) and in the anterior and posterior hypothalamus. There was also a significant amount of labelling in the archistriatum (ARCH), particularly in the nucleus taeniae (Tn), and in the lateral septum. In the midbrain, substantial uptake of labelled hormone was found in the nucleus intercollicularis (ICo). The pattern of accumulation of T in the male fowl was comparable to that for sex hormone uptake in vertebrates in general. Furthermore, accumulation was generally found in areas known to be concerned with sex hormone-dependent functions.

Animals↗
PubMed1975

Studies on the regulation of the concentration of androgens and androgen receptors in nuclei of prostatic cells.

Experiments were performed to assess the effect of intracellular androgen metabolism and the availability of cytoplasmic receptors on the concentration of androgens and androgen receptors in nuclei of prostatic cells. It was found that androgens are incorporated into the nucleus by a regulated, selective process which appears to limit the type and amount of androgen transported across the nuclear membrane. The metabolic conversion of testosterone to dihydrotestosterone which takes place in cytoplasm does not reduce transport and, very likely, affects only the ratio of testosterone and dihydrotestosterone transferred into the nucleus. In vivo, when the intranuclear concentration of androgens approaches 250 nM (8 pmol per mg DNA), an apparent concentration ceiling is reached even in the presence of a downward concentration gradient that would be expected to promote further transport across the nuclear membrane. This finding strongly suggests that in vivo the nuclear membrane acts as a barrier to the passage of androgens and, therefore, mitigates against the possibility that passive diffusion is an important mechanism of afferent transport of androgens into the nucleus. The ability of the nucleus to concentrate testosterone and dihydrotestosterone was clearly demonstrated in vivo when cytoplasmic concentrations of androgens of approximately 20 nM were accompanied by intranuclear concentrations in the vicinity of 250 nM. Since the measured concentration of testosterone and dihydrotestosterone in prostate of several species fall within the 5-20 nM range, it is evident that androgen concentrations in the nucleus as high as 250 nM may be typical of the physiological steady state. At the latter concentration the nucleus contains 60 000 androgen molecules: in approximate terms one third of this total is bound to a large molecular weight component of the nucleus, one third is bound to a 3.3 S receptor and one third is free or loosely bound. Since 60 000 androgen molecules and 20 000 receptor molecules appear in the nucleus before transport stops, it seems that the quantity of 4.4 S cytoplasmic receptor estimated at 174 plus or minus 24 pmol per mg protein (equivalent to about 8000 molecules per cell) is insufficient to account for the total influx of androgens and androgen receptors into the nucleus. Thus, although these results support the view that cytoplasmic receptors and the capacity to transport androgens are closely linked phenotypic markers of intracellular steroid hormone action, they suggest that the control of androgen concentration in the nucleus is achieved in a more intricate fashion than simply through a dependence on the presumed translocation of 4.4 S androgen-receptor complex into the nucleus.

Animals↗