HORMONAL REGULATION OF FOLLICLE-STIMULATING HORMONE RECEPTORS IN THE TESTES OF JAPANESE QUAIL

1980 ◽  
Vol 85 (3) ◽  
pp. 511-518 ◽  
Author(s):  
KAZUYOSHI TSUTSUI ◽  
SUSUMU ISHII
Keyword(s):  
Sertoli Cell ◽  
Japanese Quail ◽  
Binding Sites ◽  
Hormonal Regulation ◽  
Hormone Receptors ◽  
Fold Increase ◽  
Hormone Treatment ◽  
Testicular Development ◽  
Plot Analysis ◽  
Testicular Weight

The effects of gonadotrophins and testosterone on the binding of 125I-labelled rat FSH to a testicular homogenate of hypophysectomized Japanese quail have been studied. Hypophysectomy resulted in rapid decrease in the binding of FSH per testis but did not change the binding per unit testicular weight, suggesting a decrease in FSH binding per Sertoli cell. Injections of NIH-FSH-S12 to hypophysectomized birds (100 pg/day) for 5 days induced hypertrophy of Sertoli cells and 2·2-fold increase in the binding of FSH per Sertoli cell. Injections of testosterone to hypophysectomized birds (5·0 mg/day) for 5 days also increased the binding of FSH per Sertoli cell 2·3-fold, but did not change the cell size. Combined administration of FSH and testosterone induced 4·4-fold increase in the binding of FSH per Sertoli cell and also marked hypertrophy. The Scatchard plot analysis of the binding of FSH to the testicular preparation of hypophysectomized birds treated simultaneously with FSH and testosterone showed that the number of the binding sites, but not the affinity of the binding, was increased by the hormone treatment. Synergistic action of FSH and testosterone was observed in the increase of not only the number of the FSH binding sites but also in testicular weight and the number of spermatogonia and spermatocytes. These results indicated that FSH receptors in the testes of Japanese quail are regulated by FSH and testosterone. It is suggested that FSH acting synergistically with testosterone increases the sensitivity of the testis to FSH itself by increasing FSH receptors. This self-potentiation mechanism may enable rapid testicular development in photostimulated birds and mammals at puberty.

scholarly journals Fate of Internalized Thyrotropin-Releasing Hormone Receptors Monitored with a Timer Fusion Protein

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3095-3100 ◽  
Author(s):  
Laurie B. Cook ◽  
Patricia M. Hinkle
Keyword(s):  
Plasma Membrane ◽  
Binding Sites ◽  
Hormone Receptors ◽  
Inositol Phosphate ◽  
Fold Increase ◽  
Receptor Internalization ◽  
Free Calcium ◽  
Surface Binding ◽  
Cytoplasmic Vesicles ◽  
Trh Receptors

Abstract Trafficking of TRH receptors was studied in a stable HEK293 cell line expressing receptor fused to a Timer protein (TRHR-Timer) that spontaneously changes from green to red over 10 h. Cells expressing TRHR-Timer responded to TRH with an 11-fold increase in inositol phosphate formation, increased intracellular free calcium, and internalization of 75% of bound [3H][N3-methyl-His2]TRH within 10 min. After a 20-min exposure to TRH at 37 C, 75–80% of surface binding sites disappeared as receptors internalized. When TRH was removed and cells incubated in hormone-free medium, approximately 75% of [3H][N3-methyl-His2]TRH binding sites reappeared at the surface over the next 2 h with or without cycloheximide. Trafficking of TRHR-Timer was monitored microscopically after addition and withdrawal of TRH. In untreated cells, both new (green) and old (red) receptors were seen at the plasma membrane, and TRH caused rapid movement of young and old receptors into cytoplasmic vesicles. When TRH was withdrawn, some TRHR-Timer reappeared at the plasma membrane after several hours, but much of the internalized receptor remained intracellular in vesicles that condensed to larger structures in perinuclear regions deeper within the cell. Strikingly, receptors that moved to the plasma membrane were generally younger (more green) than those that underwent endocytosis. There was no change in the red to green ratio over the course of the experiment in cells exposed to vehicle. The results indicate that, after agonist-driven receptor internalization, the plasma membrane is replenished with younger receptors, arising either from an intracellular pool or preferential recycling of younger receptors.

Aromatase and 11β-hydroxysteroid dehydrogenase 2 localisation in the testes of pigs from birth to puberty linked to changes of hormone pattern and testicular morphology

2008 ◽  
Vol 20 (4) ◽  
pp. 505 ◽  
Author(s):  
A. Wagner ◽  
R. Claus
Keyword(s):  
Blood Plasma ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Leydig Cells ◽  
Hydroxysteroid Dehydrogenase ◽  
Blood Collection ◽  
Testicular Development ◽  
Post Mortem ◽  
Cell Numbers ◽  
Testicular Morphology

Oestrogens and glucocorticoids are important for spermatogenesis and are regulated via aromatase for oestradiol synthesis and 11β-hydroxysteroid dehydrogenase 2 (11β-HSD 2) as an inactivator of cortisol. In the present study postnatal changes of these two enzymes were monitored together with testicular development and hormone concentrations. Pigs were assigned to three periods: Weeks 0–5, Weeks 5–11 or Weeks 11–17. In Period 1, groups of four piglets were killed after each week. Blood plasma and testes were sampled immediately post mortem. For Periods 2 and 3, groups of six pigs were fitted with vein catheters for daily blood collection. Testes from all pigs were obtained after killing. Levels of testosterone, oestradiol, LH, FSH and cortisol were determined radioimmunologically. The 11β-HSD 2- and aromatase-expressing cells were stained immunocytochemically. All hormones were maximal 2 weeks after birth. A rise of LH, testosterone and oestradiol occurred again at Week 17. FSH and cortisol remained basal. Parallel to the first postnatal rise, the presence of aromatase and 11β-HSD 2 in Leydig cells increased, together with germ and Sertoli cell numbers. Expression was low from 3 to 5 weeks, was resumed after Week 5 and was maximal at Week 17. The amount of 11β-HSD 2 in germ cells was greatest at birth, decreased thereafter and was absent after Week 3.

scholarly journals Enhanced Sexual Behaviors and Androgen Receptor Immunoreactivity in the Male Progesterone Receptor Knockout Mouse

Endocrinology ◽  
2005 ◽  
Vol 146 (10) ◽  
pp. 4340-4348 ◽  
Author(s):  
Johanna S. Schneider ◽  
Carly Burgess ◽  
Nicole C. Sleiter ◽  
Lydia L. DonCarlos ◽  
John P. Lydon ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Androgen Receptor ◽  
Progesterone Receptor ◽  
Sexual Behaviors ◽  
Gene Deletion ◽  
Biological Significance ◽  
Receptor Expression ◽  
Androgen Receptor Expression ◽  
Testicular Development ◽  
Testicular Weight

Reproductive and behavioral functions of progesterone receptors (PRs) in males were assessed by examining consequences of PR gene deletion. Basal hormone levels were measured in male progesterone receptor knockout (PRKO) mice and compared to wild-type (WT) counterparts. RIA of serum LH, testosterone, and progesterone levels revealed no significant differences. Levels of FSH were moderately but significantly lower and inhibin levels were higher in PRKOs; these differences were not accompanied by gross differences in testicular weight or morphology. PRKOs exhibited significant alterations in sexual behavior. In initial tests PRKOs exhibited reduced latency to mount, compared with WT. In second sessions, PRKOs again showed a significantly reduced latency to mount and increased likelihood of achieving ejaculation. RU486 treatment in WT produced increased mount and intromission frequency and decreased latency to intromission. In anxiety-related behavior tests, PRKO mice exhibited intermediate anxiety levels, compared with WT, suggesting that enhanced sexual behavior in PRKOs is not secondary to reduced anxiety. Immunohistochemical analysis revealed significantly enhanced androgen receptor expression in the medial preoptic nucleus and bed nucleus of the stria terminalis of PRKO. We conclude that testicular development and function and homeostatic regulation of the hypothalamic-pituitary testicular axis are altered to a lesser extent by PR gene deletion. In contrast, PR appears to play a substantial role in inhibiting the anticipatory/motivational components of male sexual behavior in the mouse. The biological significance of this inhibitory mechanism and the extent to which it is mediated by reduced androgen receptor expression remain to be clarified.

Platelet-derived growth factor induces rapid and sustained tyrosine phosphorylation of phospholipase C-gamma in quiescent BALB/c 3T3 cells

1989 ◽  
Vol 9 (7) ◽  
pp. 2934-2943
Author(s):  
M I Wahl ◽  
N E Olashaw ◽  
S Nishibe ◽  
S G Rhee ◽  
W J Pledger ◽  
...  
Keyword(s):  
Growth Factor ◽  
Phospholipase C ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Hormonal Regulation ◽  
Growth Factor Receptor ◽  
Fold Increase ◽  
Platelet Derived Growth Factor ◽  
3T3 Cells ◽  
Pdgf Stimulation

Platelet-derived growth factor (PDGF) stimulates the proliferation of quiescent fibroblasts through a series of events initiated by activation of tyrosine kinase activity of the PDGF receptor at the cell surface. Physiologically significant substrates for this or other growth factor receptor or oncogene tyrosine kinases have been difficult to identify. Phospholipase C (PLC), a key enzyme of the phosphoinositide pathway, is believed to be an important site for hormonal regulation of the hydrolysis of phosphatidylinositol 4,5-bisphosphate, which produces the intracellular second-messenger molecules inositol 1,4,5-trisphosphate and 1,2-diacylglycerol. Treatment of BALB/c 3T3 cells with PDGF led to a rapid (within 1 min) and significant (greater than 50-fold) increase in PLC activity, as detected in eluates of proteins from a phosphotyrosine immunoaffinity matrix. This PDGF-stimulated increase in phosphotyrosine-immunopurified PLC activity occurred for up to 12 h after addition of growth factor to quiescent cells. Interestingly, the PDGF stimulation occurred at 3 as well as 37 degrees C and in the absence or presence of extracellular Ca2+. Immunoprecipitation of cellular proteins with monoclonal antibodies specific for three distinct cytosolic PLC isozymes demonstrated the presence of a 145-kilodalton isozyme, PLC-gamma (formerly PLC-II), in BALB/c 3T3 cells. Furthermore, these immunoprecipitation studies showed that PLC-gamma is rapidly phosphorylated on tyrosine residues after PDGF stimulation. The results suggest that mitogenic signaling by PDGF is coincident with tyrosine phosphorylation of PLC-gamma.

EFFECT OF SODIUM MOLYBDATE ON THE INTERACTION OF ANDROGENS AND PROGESTINS WITH BINDING PROTEINS IN HUMAN HYPERPLASTIC PROSTATIC TISSUE

1982 ◽  
Vol 92 (1) ◽  
pp. 95-102 ◽  
Author(s):  
D. A. N. SIRETT ◽  
J. K. GRANT
Keyword(s):  
Binding Sites ◽  
Hormone Receptors ◽  
Sodium Molybdate ◽  
Nuclear Extract ◽  
Steroid Hormone Receptors ◽  
Prostatic Tissue ◽  
Reliable Measurement ◽  
Nuclear Extracts ◽  
Steroid Binding ◽  
Androgen Binding

A reliable measurement of steroid hormone receptors is essential for attempts to correlate receptor levels with response to endocrine therapy in prostatic carcinoma. Evidence that receptors in many tissues are stabilized by sodium molybdate prompted the examination of the effects of this salt on the measurement of steroid-binding sites in human prostatic tissue. The presence of molybdate (10 mmol/l) during tissue homogenization, cytosol or nuclear extract preparation and binding-site assay led to a threefold increase in the amount of highaffinity androgen binding detected in cytosol, and a slight increase in the number of cytosol progestin-binding sites. The apparent binding affinity for steroids was increased in both cases. No effect of molybdate was observed on androgen-binding sites in nuclear extracts.

Hormonal induction of transfected genes depends on DNA topology

1990 ◽  
Vol 10 (2) ◽  
pp. 625-633
Author(s):  
B Piña ◽  
R J Haché ◽  
J Arnemann ◽  
G Chalepakis ◽  
E P Slater ◽  
...  
Keyword(s):  
Cell Line ◽  
Mammary Tumor ◽  
Binding Sites ◽  
Glucocorticoid Receptors ◽  
Hormone Receptors ◽  
Regulatory Element ◽  
Tumor Cell Line ◽  
Dna Topology ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Cell Line

Plasmids containing the hormone regulatory element of mouse mammary tumor virus linked to the thymidine kinase promoter of herpes simplex virus and the reporter gene chloramphenicol acetyltransferase of Escherichia coli respond to glucocorticoids and progestins when transfected into appropriate cells. In the human mammary tumor cell line T47D, the response to progestins, but not to glucocorticoids, is highly dependent on the topology of the transfected DNA. Although negatively supercoiled plasmids respond optimally to the synthetic progestin R5020, their linearized counterparts exhibit markedly reduced progestin inducibility. This is not due to changes in the efficiency of DNA transfection, since the amount of DNA incorporated into the cell nucleus is not significantly dependent on the initial topology of the plasmids. In contrast, cotransfection experiments with glucocorticoid receptor cDNA in the same cell line show no significant influence of DNA topology on induction by dexamethasone. A similar result was obtained with fibroblasts that contain endogenous glucocorticoid receptors. When the distance between receptor-binding sites or between the binding sites and the promoter was increased, the dependence of progestin induction on DNA topology was more pronounced. In contrast to the original plasmid, these constructs also revealed a similar topological dependence for induction by glucocorticoids. The differential influence of DNA topology is not due to differences in the affinity of the two hormone receptors for DNA of various topologies, but probably reflects an influence of DNA topology on the interaction between different DNA-bound receptor molecules and between receptors and other transcription factors.

Hormonal regulation of iodothyronine 5'-deiodinase in rat brown adipose tissue

1986 ◽  
Vol 251 (6) ◽  
pp. E639-E643 ◽  
Author(s):  
J. E. Silva ◽  
P. R. Larsen
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Hormonal Regulation ◽  
Fold Increase ◽  
Growth Hormones ◽  
Mrna Synthesis ◽  
Brown Adipose ◽  
Streptozotocin Induced Diabetes ◽  
Complex Regulation ◽  
Intact Rats

Norepinephrine, isoproterenol, insulin, and glucagon increase the type II (low Km) iodothyronine 5'-deiodinase (5'-D) in the brown adipose tissue (BAT) of intact rats. Cycloheximide or actinomycin D blocks the increase after norepinephrine, suggesting new mRNA synthesis is required for this effect. The 3- to 10-fold increase in BAT 5'-D after insulin administration was also blocked by cycloheximide. The effects of all stimulators are blunted by fasting or streptozotocin-induced diabetes. While all these hormones have the potential for stimulating BAT 5'-D, the dose-response relationships suggest that norepinephrine and insulin are the most potent. These and our earlier studies showing additional effects of thyroid and growth hormones on BAT 5'-D point to the complex regulation of this enzyme, suggesting that the triiodothyronine produced from its action has an important role in the thermogenic response of this tissue.

Hormonal interactions with the proximal Na(+)-H+ exchanger

1990 ◽  
Vol 258 (3) ◽  
pp. F514-F521 ◽  
Author(s):  
F. A. Gesek ◽  
A. C. Schoolwerth
Keyword(s):  
Binding Sites ◽  
Time Course ◽  
Hormone Receptors ◽  
Control Level ◽  
Peptide Hormone ◽  
Ang Ii ◽  
Maximum Increase ◽  
Alpha Adrenergic Receptors ◽  
22Na Uptake ◽  
Exchange Activity

Various types of catecholamine and peptide hormone receptors have been localized to the renal cortex, with the majority of these binding sites located on the proximal tubule. Both subtypes of alpha-adrenergic receptors, angiotensin II (ANG II), parathyroid hormone (PTH), and dopamine (DA) DA-1 receptors have all demonstrated binding sites on this nephron segment. One- to two-thirds of Na+ transport in the proximal nephron is proposed to be mediated by a Na(+)-H+ exchanger. Each of these hormones has been shown to alter Na(+)-H+ exchange activity. The purpose of this study was to examine the interactions of these various hormones on proximal nephron Na(+)-H+ exchange at both physiological and pharmacological concentrations. Na(+)-H+ exchange activity was determined in isolated rat proximal segments by assessing the uptake of 22Na+ that was suppressible by the Na(+)-H+ exchange inhibitor, ethylisopropylamiloride (EIPA). Time course studies indicated that a 1-min preincubation with the hormones followed by a 1-min exposure to 22Na+ was necessary to achieve a steady-state EIPA-suppressible 22Na+ uptake. Selective alpha-adrenergic agonists produced a maximum stimulation of 22Na+ uptake at approximately 10(-6) M final concentration (less than or equal to 192% above the control level of uptake); ANG II produced a maximum increase at 10(-12) M (an 82% increase above the control level). In contrast, PTH and DA inhibited 22Na+ uptake most effectively at 10(-8) M and 10(-6) M, respectively. When submaximal (10(-9) M) concentrations of alpha-agonists were incubated in combination with ANG II, a synergistic effect was observed only with selective alpha 2-agonists.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Bovine fetal testicular development in the Nellore breed

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2551
Author(s):  
Juliana Stephany de Souza ◽  
Maria Carolina Villani Miguel ◽  
Marcos Antônio Maioli ◽  
Arthur Nelson Trali Neto ◽  
David Giraldo Arana ◽  
...  
Keyword(s):  
Germ Cells ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Principal Component ◽  
Gonadal Development ◽  
Cell Number ◽  
Testicular Development ◽  
Testosterone Concentration ◽  
Testicular Weight ◽  
Bovine Fetuses

The study of gonadal development improves the understanding of factors that can influence the reproductive development process. This study aims to characterize bovine fetal testicular development and the testosterone level in the Nellore breed. For the study, 162 bovine fetuses aged between 3 and 8 months were collected from Nellore cows at a local abattoir. The fetal age was estimated by DP=8.4+0.087L+5.46?L, where DP is the estimated pregnancy day and L represents fetal length. The fetal gonadal weight (g), width (cm), and thickness (cm) were measured. Thereafter, the gonads were submitted to classic histology processes in 3-µm-thick slices cut at 210 µm intervals. The Sertoli cells, Leydig cells, and germ cells were counted. Blood samples were collected from umbilical cords for testosterone levels. The data were analyzed using the Spearman correlation test followed by Principal Component Analysis and one-way ANOVA to compare the averages between months. The testicular weight and volume were found to have a positive correlation with the numbers of Sertoli cells (r = 0.84; p < 0.0001 and r = 0.92; p < 0.0001, respectively), Leydig cells (r = 0.80; p < 0.0001 and r = 0.90; p < 0.0001, respectively), and germ cells (r = 0.84; p < 0.0001 and r = 0.93; p < 0.0001, respectively) and to be negatively correlated with testosterone plasmatic concentration (r = -0.31; p = 0.0001 and r = -0.22; p = 0.006, respectively) during pregnancy. After the fifth month, the numbers of Sertoli cells, Leydig cells and germ cells differed (p < 0.0001) from the following gestational months. The highest testosterone concentration (p = 0.007) was observed in the fifth month of gestation and was followed by a concentration decrease in the seventh and eighth months. The increase in cell quantity was responsible for the increase in testicular weight and volume during fetal development. On the other hand, the testosterone concentration followed the increase in testicular weight and volume until the 7th month of gestation and regressed during the 8th and 9th months, in addition to the increase in cell number.

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