5β-Reductase activity in the brain and cloacal gland of male and female embryos in the Japanese quail (Coturnix coturnix japonica)

1984 ◽  
Vol 102 (1) ◽  
pp. 77-81 ◽  
Author(s):  
J. Balthazart ◽  
M. A. Ottinger
Keyword(s):  
Reductase Activity ◽  
Young Male ◽  
Testosterone Metabolism ◽  
Male And Female ◽  
Coturnix Coturnix ◽  
Female Quail ◽  
In Vitro Technique ◽  
The Brain ◽  
Cloacal Gland

ABSTRACT Testosterone metabolism was studied by an in-vitro technique in the brain and cloacal gland of young male and female quail at different ages ranging from 7 days of incubation to 2 days after hatching. Very active metabolism, leading almost exclusively to the production of 5β-reduced compounds, was observed. 5β-Reductase activity remained high throughout the incubation period in the hypothalamus, decreased around the time of hatching in the cerebellum and decreased progressively between days 7 and 15 of incubation in the cloacal gland. These changes could be involved in the control of sexual differentiation: the high 5β-reductase in the brain possibly protects males from being behaviourally demasculinized by their endogenous testosterone while the decreasing 5β-reductase in the cloacal gland would progressively permit the masculinization of that structure. J. Endocr. (1984) 102, 77–81

Changes in testosterone metabolism by the brain and cloacal gland during sexual maturation in the Japanese quail (Coturnix coturnix japonica)

1984 ◽  
Vol 100 (1) ◽  
pp. 13-18 ◽  
Author(s):  
J. Balthazart ◽  
M. Schumacher
Keyword(s):  
Japanese Quail ◽  
Sexual Maturation ◽  
Reductase Activity ◽  
Coturnix Japonica ◽  
Testosterone Metabolism ◽  
Coturnix Coturnix ◽  
The Brain ◽  
Very High ◽  
Cloacal Gland

ABSTRACT Testosterone metabolism in the brain and pituitary and cloacal glands of male and female Japanese quail was studied in vitro during sexual maturation (from 1 day to 5 weeks after hatching). The production of 5α-dihydrotestosterone in the hyperstriatum and cloacal gland and that of androstenedione in the cloacal gland of males was highest at 1 day after hatching, which could be related to the peak of plasma androgens previously demonstrated in neonatal quail. 5β-Reductase activity was very high in the brain, but not the pituitary or cloacal glands of young chicks and decreased markedly, especially in the hypothalamus, during sexual maturation. As 5β-reduced metabolites of testosterone are inactive androgens, it is suggested that the decrease of 5β-reductase activity with age corresponds to a potentiation of the effects of testosterone at the level of the brain. J. Endocr. (1984) 100, 13–18

Relative potencies of testosterone and 5α-dihydrotestosterone on crowing and cloacal gland growth in the Japanese quail (Coturnix coturnix japonica)

1984 ◽  
Vol 100 (1) ◽  
pp. 19-23 ◽  
Author(s):  
J. Balthazart ◽  
M. Schumacher ◽  
G. Malacarne
Keyword(s):  
Coturnix Japonica ◽  
Coturnix Coturnix Japonica ◽  
Coturnix Coturnix ◽  
Behavioural Activity ◽  
Age Related ◽  
Female Quail ◽  
The Brain ◽  
Relative Potencies ◽  
Cloacal Gland ◽  
Age Related Changes

ABSTRACT It has been suggested that testosterone is less effective at inducing crowing behaviour in young birds than in adults because of the presence of higher levels of steroid 5β-reductase in the young brain, which converts testosterone to inactive 5β-reduced metabolites. This hypothesis was tested indirectly by comparing the relative potencies of 5α-dihydrotestosterone (5α-DHT), which cannot be converted to 5β-metabolities, and testosterone at inducing crowing in young gonadectomized male and female quail. The promotion of cloacal gland growth by these treatments was also assessed since there are no age-related changes in 5β-reductase in this organ. Silicone elastomer implants (2·5, 5 and 10 mm) containing 5α-DHT were more effective at stimulating crowing than similar implants of testosterone whilst there was little difference in their potency at inducing cloacal gland growth. These results are consistent with the hypothesis that brain steroid 5β-reductase regulates the behavioural activity of testosterone in the brain of young birds. J. Endocr. (1984) 100, 19–23

Inhibition of testosterone metabolism in the brain and cloacal gland of the quail by specific inhibitors and antihormones

1987 ◽  
Vol 112 (2) ◽  
pp. 189-195 ◽  
Author(s):  
C. Alexandre ◽  
J. Balthazart
Keyword(s):  
Reductase Inhibitor ◽  
Aromatase Activity ◽  
Testosterone Metabolism ◽  
In Vivo Experiments ◽  
High Doses ◽  
The Brain ◽  
Very High ◽  
Cloacal Gland

ABSTRACT The effects of antioestrogens, antiandrogens and of various inhibitors of testosterone metabolism on testosterone metabolism in the quail hypothalamus and cloacal gland were studied by an in-vitro radio-enzymatic assay. It was found that antioestrogens and antiandrogens generally had little or no effect on aromatase and 5α- and 5β-reductases of testosterone, except when used at very high doses. The 5α-reductase inhibitor, 17β-N,N-diethylcarbamoyl-4-methyl-4-aza-5α-androstan-3-one, inhibited both 5α- and 5β-dihydrotestosterone production without markedly affecting aromatase activity. Surprisingly, the aromatase inhibitor, 1,4,6-androstatriene-3,17-dione, inhibited not only the production of oestradiol but also that of 5β-dihydrotestosterone and, to a lesser extent, 5α-dihydrotestosterone. These unexpected properties should be taken into account when interpreting the results of in-vivo experiments using these compounds. J. Endocr. (1987) 112, 189–195

scholarly journals Acute Stress Differentially Affects Aromatase Activity in Specific Brain Nuclei of Adult Male and Female Quail

Endocrinology ◽  
2011 ◽  
Vol 152 (11) ◽  
pp. 4242-4251 ◽  
Author(s):  
Molly J. Dickens ◽  
Charlotte A. Cornil ◽  
Jacques Balthazart
Keyword(s):  
Reproductive Behavior ◽  
Acute Stress ◽  
Aromatase Activity ◽  
Brain Nuclei ◽  
Male And Female ◽  
Estrogen Production ◽  
Female Quail ◽  
Male Reproductive Behavior ◽  
The Individual ◽  
The Brain

The rapid and temporary suppression of reproductive behavior is often assumed to be an important feature of the adaptive acute stress response. However, how this suppression operates at the mechanistic level is poorly understood. The enzyme aromatase converts testosterone to estradiol in the brain to activate reproductive behavior in male Japanese quail (Coturnix japonica). The discovery of rapid and reversible modification of aromatase activity (AA) provides a potential mechanism for fast, stress-induced changes in behavior. We investigated the effects of acute stress on AA in both sexes by measuring enzyme activity in all aromatase-expressing brain nuclei before, during, and after 30 min of acute restraint stress. We show here that acute stress rapidly alters AA in the male and female brain and that these changes are specific to the brain nuclei and sex of the individual. Specifically, acute stress rapidly (5 min) increased AA in the male medial preoptic nucleus, a region controlling male reproductive behavior; in females, a similar increase was also observed, but it appeared delayed (15 min) and had smaller amplitude. In the ventromedial and tuberal hypothalamus, regions associated with female reproductive behavior, stress induced a quick and sustained decrease in AA in females, but in males, only a slight increase (ventromedial) or no change (tuberal) in AA was observed. Effects of acute stress on brain estrogen production, therefore, represent one potential way through which stress affects reproduction.

scholarly journals The Effect of Different Foam Concentrations on Sperm Motility in Japanese Quail

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Avishek Biswas ◽  
O. S. Ranganatha ◽  
Jag Mohan
Keyword(s):  
Sperm Motility ◽  
Japanese Quail ◽  
Normal Saline ◽  
Coturnix Japonica ◽  
Coturnix Coturnix Japonica ◽  
Coturnix Coturnix ◽  
Sperm Survival ◽  
Foam Production ◽  
Cloacal Gland

A study was conducted to determine the effect of foam extract on sperm motility in the male Japanese quail (Coturnix coturnix japonica). Adult male quails (12 weeks) of heavy body weight strain were housed in individual cages and divided into 5 groups according to the size of their cloacal glands. The data indicated that the size of the cloacal gland was positively correlated with the frequency of foam secretion and total foam production. One gram of freshly collected clean foam was mixed with 1.0 mL of normal saline and homogenized for 10 minutes. After centrifugation at 35 000 rpm, the supernatant was used as 100% foam extract. The extract was diluted to 1:40, 1:20, 1:10, and 1:4 with normal saline to produce 2.5, 5.0, 10, and 25% foam extracts, respectively. 5% foam extract enhanced sperm survival at room temperature (30°–35°C) for 2 to 3 hrs, whereas higher concentrations (10% and above) suppressed sperm motility. From this study, it may be concluded that foam secretion and quantity of foam are directly proportional to the size of the cloacal gland and that the foam enhances and prolongs sperm motility, in vitro at an optimum concentration of 5%.

Androgen 5α-reductase and 3α-hydroxysteroid dehydrogenase activities in ventral prostate epithelial and stromal cells from immature and mature rats

1983 ◽  
Vol 99 (1) ◽  
pp. 131-139 ◽  
Author(s):  
J. Orlowski ◽  
C. E. Bird ◽  
A. F. Clark
Keyword(s):  
Epithelial Cells ◽  
Stromal Cells ◽  
Reductase Activity ◽  
Age Groups ◽  
Cell Types ◽  
Hydroxysteroid Dehydrogenase ◽  
Ventral Prostate ◽  
Testosterone Metabolism ◽  
Immature Rats

To study androgen-mediated differentiation in the rat ventral prostate, we separated the two principal cell types (epithelial and stromal) derived from prostates of immature and mature rats on two continuous Percoll gradients. Cells were immediately placed in culture medium. Testosterone metabolism by the two prostatic cell types was evaluated using [3H]testosterone and quantifying the formation of 5α-[3H]dihydrotestosterone (5α-DHT) and 5α-[3H]androstane-(3α or 3β), 17β-diols. In epithelial cells from both immature and mature rat prostates the major testosterone metabolites were 5α-DHT and 5α-androstane-3α, 17β-diol. Stromal cells metabolized less testosterone than did the epithelial cells. Differences in the relative levels of the various metabolites were observed for the two age groups. To examine in more detail the changes in testosterone metabolism observed in vitro both types of cells and unfractionated cells from immature and mature rat prostates were assayed for testosterone 5α-reductase (using testosterone as substrate) and 3α-hydroxysteroid dehydrogenase (using 5α-DHT as substrate) activities (expressed as pmol substrate reduced/min per 106 cells). In immature rats both 5α-reductase and 3α-hydroxysteroid dehydrogenase activities were localized in the epithelial cell fraction (17 and 52 respectively); stromal cells showed lower 5α-reductase and 3α-hydroxysteroid dehydrogenase activity (4 and 4). Relative to epithelial cells from immature rats epithelial cells from mature rats showed a decrease in 5α-reductase (7) and an increase in 3α-hydroxysteroid dehydrogenase (160) activity while stromal 5α-reductase showed little change (3) and 3α-hydroxysteroid dehydrogenase increased to 22. Because there are more epithelial than stromal cells in the rat prostate, the former can be considered important sites for 5α-reductase and 3α-hydroxysteroid dehydrogenase activities. This contrasts with the human prostate where there is more 5α-reductase activity in the stroma than in the epithelium.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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