scholarly journals Fasting Enhances Pyroglutamyl Peptidase II Activity in Tanycytes of the Mediobasal Hypothalamus of Male Adult Rats

Endocrinology ◽  
2015 ◽  
Vol 156 (7) ◽  
pp. 2713-2723 ◽  
Author(s):  
Iván Lazcano ◽  
Agustina Cabral ◽  
Rosa María Uribe ◽  
Lorraine Jaimes-Hoy ◽  
Mario Perello ◽  
...  
Keyword(s):  
Male Rats ◽  
Mrna Levels ◽  
Mediobasal Hypothalamus ◽  
Adult Rats ◽  
Male Adult ◽  
In Situ Hybridization Histochemistry ◽  
Corticosterone Treatment ◽  
Hpt Axis ◽  
Partial Reversion

Fasting down-regulates the hypothalamus-pituitary-thyroid (HPT) axis activity through a reduction of TRH synthesis in neurons of the parvocellular paraventricular nucleus of the hypothalamus (PVN). These TRH neurons project to the median eminence (ME), where TRH terminals are close to the cytoplasmic extensions of β2 tanycytes. Tanycytes express pyroglutamyl peptidase II (PPII), the TRH-degrading ectoenzyme that controls the amount of TRH that reaches the anterior pituitary. We tested the hypothesis that regulation of ME PPII activity is another mechanism by which fasting affects the activity of the HPT axis. Semiquantitative in situ hybridization histochemistry data indicated that PPII and deiodinase 2 mRNA levels increased in tanycytes after 48 hours of fasting. This increase was transitory, followed by an increase of PPII activity in the ME, and a partial reversion of the reduction in PVN pro-TRH mRNA levels and the number of TRH neurons detected by immunohistochemistry. In fed animals, adrenalectomy and corticosterone treatment did not change ME PPII activity 72 hours later. Methimazole-induced hypothyroidism produced a profound drop in tanycytes PPII mRNA levels, which was reverted by 3 days of treatment with T4. The activity of thyroliberinase, the serum isoform of PPII, was increased at most fasting time points studied. We conclude that delayed increases in both the ME PPII as well as the thyroliberinase activities in fasted male rats may facilitate the maintenance of the deep down-regulation of the HPT axis function, despite a partial reactivation of TRH expression in the PVN.

Gene expression in the rat supraoptic nucleus induced by chronic hyperosmolality versus hyposmolality

2000 ◽  
Vol 279 (4) ◽  
pp. R1239-R1250 ◽  
Author(s):  
Eric Glasgow ◽  
Takashi Murase ◽  
Bingjun Zhang ◽  
Joseph G. Verbalis ◽  
Harold Gainer
Keyword(s):  
Gene Expression ◽  
Supraoptic Nucleus ◽  
Cdna Libraries ◽  
Global Changes ◽  
Cdna Clones ◽  
Mrna Levels ◽  
Magnocellular Neurons ◽  
In Situ Hybridization Histochemistry ◽  
Functional Classes

Magnocellular neurons of the hypothalamo-neurohypophysial system play a fundamental role in the maintenance of body homeostasis by secreting vasopressin and oxytocin in response to systemic osmotic perturbations. During chronic hyperosmolality, vasopressin and oxytocin mRNA levels increase twofold, whereas, during chronic hyposmolality, these mRNA levels decrease to 10–20% of that of normoosmolar control animals. To determine what other genes respond to these osmotic perturbations, we have analyzed gene expression during chronic hyper- versus hyponatremia. Thirty-seven cDNA clones were isolated by differentially screening cDNA libraries that were generated from supraoptic nucleus tissue punches from hyper- or hyponatremic rats. Further analysis of 12 of these cDNAs by in situ hybridization histochemistry confirmed that they are osmotically regulated. These cDNAs represent a variety of functional classes and include cytochrome oxidase, tubulin, Na+-K+-ATPase, spectrin, PEP-19, calmodulin, GTPase, DnaJ-like, clathrin-associated, synaptic glycoprotein, regulator of GTPase stimulation, and gene for oligodendrocyte lineage-myelin basic proteins. This analysis therefore suggests that adaptation to chronic osmotic stress results in global changes in gene expression in the magnocellular neurons of the supraoptic nucleus.

Expression of acetylcholine receptor mRNAs in atrophying and nonatrophying skeletal muscles of old rats

1998 ◽  
Vol 85 (5) ◽  
pp. 1903-1908 ◽  
Author(s):  
Ronald R. Gomes ◽  
Frank W. Booth
Keyword(s):  
Skeletal Muscle ◽  
Acetylcholine Receptor ◽  
Biceps Brachii ◽  
Male Rats ◽  
Brown Norway ◽  
Mrna Levels ◽  
Adult Rats ◽  
Γ Subunit ◽  
Age Related ◽  
Old Rats

We examined the age-related association in skeletal muscle between atrophy and expression of mRNAs encoding both the γ-subunit of the nicotinic acetylcholine receptor (AChR), and myogenin, a transcription factor that upregulates expression of the γ-subunit promoter. Gastrocnemius and biceps brachii muscles were collected from young (2-mo-old), adult (18-mo-old), and old (31-mo-old) Fischer 344/Brown Norway F1 generation cross male rats. In the gastrocnemius muscles of old vs. young and adult rats, lower muscle mass was accompanied by significantly elevated AChR γ-subunit and myogenin mRNA levels. In contrast, the biceps brachii muscle exhibited neither atrophy nor as drastic a change in AChR γ-subunit and myogenin mRNA levels with age. Expression of the AChR ε-subunit mRNA did not change with age in either gastrocnemius or biceps brachii muscles. Thus changes in skeletal muscle AChR γ-subunit and myogenin mRNA levels may be more related to atrophy than to chronological age in old rats.

scholarly journals Suppressor of cytokine signaling 3 knockdown in the mediobasal hypothalamus: counterintuitive effects on energy balance

2010 ◽  
Vol 45 (5) ◽  
pp. 341-353 ◽  
Author(s):  
M W A de Backer ◽  
M A D Brans ◽  
A J van Rozen ◽  
E M van der Zwaal ◽  
M C M Luijendijk ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Energy Balance ◽  
Viral Vectors ◽  
Body Weight Gain ◽  
Cytokine Signaling ◽  
Dark Phase ◽  
Mrna Levels ◽  
Mediobasal Hypothalamus ◽  
Suppressor Of Cytokine Signaling ◽  
Adult Rats

An increase in brain suppressor of cytokine signaling 3 (SOCS3) has been implicated in the development of both leptin and insulin resistance. Socs3 mRNA is localized throughout the brain, and it remains unclear which brain areas are involved in the effect of SOCS3 levels on energy balance. We investigated the role of SOCS3 expressed in the mediobasal hypothalamus (MBH) in the development of diet-induced obesity in adult rats. Socs3 mRNA was down-regulated by local injection of adeno-associated viral vectors expressing a short hairpin directed against Socs3, after which we determined the response to high-fat high-sucrose choice diet. In contrast to neuronal Socs3 knockout mice, rats with SOCS3 knockdown limited to the MBH showed increased body weight gain, larger amounts of white adipose tissue, and higher leptin concentrations at the end of the experiment. These effects were partly due to the decrease in locomotor activity, as 24 h food intake was comparable with controls. In addition, rats with Socs3 knockdown in the MBH showed alterations in their meal patterns: average meal size in the light period was increased and was accompanied by a compensatory decrease in meal frequency in the dark phase. In addition, neuropeptide Y (Npy) mRNA levels were significantly increased in the arcuate nucleus of Socs3 knockdown rats. Since leptin is known to stimulate Npy transcription in the absence of Socs3, these data suggest that knockdown of Socs3 mRNA limited to the MBH increases Npy mRNA levels, which subsequently decreases locomotor activity and alters feeding patterns.

scholarly journals Expression of Vesicular Glutamate Transporter-2 in Gonadotrope and Thyrotrope Cells of the Rat Pituitary. Regulation by Estrogen and Thyroid Hormone Status

Endocrinology ◽  
2006 ◽  
Vol 147 (8) ◽  
pp. 3818-3825 ◽  
Author(s):  
Erik Hrabovszky ◽  
Imre Kalló ◽  
Gergely F. Turi ◽  
Katalin May ◽  
Gábor Wittmann ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Thyroid Hormone ◽  
Glutamate Transporter ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Mrna Levels ◽  
Vesicular Glutamate Transporter ◽  
Local Synthesis ◽  
Enhanced Secretion

Immunocytochemical studies of the rat adenohypophysis identified a cell population that exhibits immunoreactivity for type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype. The in situ hybridization detection of VGLUT2 mRNA expression in adenohypophysial cells verified that VGLUT2 immunoreactivity is due to local synthesis of authentic VGLUT2. Dual-immunofluorescent studies of the hypophyses from male rats showed the presence of VGLUT2 in high percentages of LH (93.3 ± 1.3%)-, FSH (44.7 ± 3.9%)-, and TSH (70.0 ± 5.6%)-immunoreactive cells and its much lower incidence in cells of the prolactin, GH, and ACTH phenotypes. Quantitative in situ hybridization studies have established that the administration of a single dose of 17-β-estradiol (20 μg/kg; sc) to ovariectomized rats significantly elevated VGLUT2 mRNA in the adenohypophysis 16 h postinjection. Thyroid hormone dependence of VGLUT2 expression was addressed by the comparison of hybridization signals in animal models of hypo- and hyperthyroidism to those in euthyroid controls. Although hyperthyroidism had no effect on VGLUT2 mRNA, hypothyroidism increased adenohypophysial VGLUT2 mRNA levels. This coincided with a decreased ratio of VGLUT2-immunoreactive TSH cells, regarded as a sign of enhanced secretion. The presence of the glutamate marker VGLUT2 in gonadotrope and thyrotrope cells, and its up-regulation by estrogen or hypothyroidism, address the possibility that endocrine cells of the adenohypophysis may cosecrete glutamate with peptide hormones in an estrogen- and thyroid status-regulated manner. The exact roles of endogenous glutamate observed primarily in gonadotropes and thyrotropes, including its putative involvement in autocrine/paracrine regulatory mechanisms, will require clarification.

Differential regulation of FSH and inhibin gene expression and synthesis by testosterone in immature and mature male rats

1993 ◽  
Vol 137 (1) ◽  
pp. 69-79 ◽  
Author(s):  
A. Perheentupa ◽  
M. Bergendahl ◽  
F. H. de Jong ◽  
I. Huhtaniemi
Keyword(s):  
Gene Expression ◽  
Combined Treatment ◽  
Male Rats ◽  
Mrna Levels ◽  
Partial Recovery ◽  
Β Subunit ◽  
Adult Rats ◽  
Testosterone Treatment ◽  
Subunit Mrna ◽  
Immature Rats

ABSTRACT Direct effects of testosterone on gonadotrophins at the pituitary level were studied in intact and castrated immature (age 10 days) and mature (70 days) male rats. Gonadotrophin-releasing hormone action was blocked by treatment with a potent GnRH antagonist, Ac-d-pClPhe-d-pClPhe-d-Trp-Ser-Tyr-d-Arg-Leu-Arg-Pro-d-Ala-NH2CH3COOH (Ant; Organon 30276; 1·0 mg/kg body weight per day) injected subcutaneously. Silicone elastomer capsules were used for the testosterone treatment. Both treatments commenced on the day of orchiectomy and lasted for 7 days. In adult male rats Ant treatment suppressed serum testosterone from 9·5 ± 2·5 (s.e.m.) nmol/l to below the limit of detection (< 0·10 nmol/l; P < 0·01), and the testosterone implants reversed the decrease. Treatment with Ant decreased the pituitary content of FSH-β subunit mRNA in intact and orchiectomized rats to 14% of their respective controls (P < 0·01). These levels were increased to 80–81% of controls (not significant) in both groups by combined treatment with testosterone and Ant. Orchiectomy alone increased FSH-β subunit mRNA by 202% (P < 0·01). In intact immature rats Ant treatment decreased the level of pituitary FSH-β subunit mRNA to 21% (P<0·01), and a partial recovery (P < 0·01) to 42% of controls was observed with combined Ant + testosterone treatment. In contrast, in orchiectomized immature rats, where ANT decreased FSH-β subunit levels to 48% of controls (P < 0·01), testosterone was able to reverse these mRNA levels completely (114% of controls). No evidence for the direct pituitary effects of testosterone were found in the mRNA of the common α or LH-β subunits. In adult rats, the testicular inhibin α and βA subunit mRNA levels were increased (P < 0·01) by Ant + testosterone compared with Ant-treated animals, but there were no differences in serum immunoreactive inhibin between any of the uncastrated adult groups. In intact immature rats, Ant + testosterone treatment increased (P < 0·01) inhibin βA subunit mRNA levels compared with controls and Ant-treated animals. Ant decreased the level of peripheral inhibin immunoreactivity from 8·3 ± 2·0 U/ml to 2·1 ± 0·4 U/ml (P < 0·01) and testosterone reversed it to 5·8 ± 0·6 U/ml (not significant). In conclusion, our observations indicated that testosterone is able to stimulate FSH gene expression and secretion directly in immature and adult rats, but the testosterone response is enhanced at both ages by orchiectomy, even more so in the immature rat. This may be explained by age differences in the contribution of testicular inhibin to the regulation of FSH synthesis and secretion at the pituitary level. Journal of Endocrinology (1993) 137, 69–79

scholarly journals Myostatin and insulin-like growth factor-I and -II expression in the muscle of rats exposed to the microgravity environment of the NeuroLab space shuttle flight

2000 ◽  
Vol 167 (3) ◽  
pp. 417-428 ◽  
Author(s):  
R Lalani ◽  
S Bhasin ◽  
F Byhower ◽  
R Tarnuzzer ◽  
M Grant ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Recovery Period ◽  
Microgravity Environment ◽  
Mrna Levels ◽  
Adult Rats ◽  
Male Adult ◽  
Western Blots ◽  
Igf I

The mechanism of the loss of skeletal muscle mass that occurs during spaceflight is not well understood. Myostatin has been proposed as a negative modulator of muscle mass, and IGF-I and IGF-II are known positive regulators of muscle differentiation and growth. We investigated whether muscle loss associated with spaceflight is accompanied by increased levels of myostatin and a reduction in IGF-I and -II levels in the muscle, and whether these changes correlate with an increase in muscle proteolysis and apoptosis. Twelve male adult rats sent on the 17-day NASA STS-90 NeuroLab space flight were divided upon return to earth into two groups, and killed either 1 day later (R1) or after 13 days of acclimatization (R13). Ground-based control rats were maintained for the same periods in either vivarium (R3 and R15, respectively), or flight-simulated cages (R5 and R17, respectively). RNA and protein were isolated from the tibialis anterior, biceps femoris, quadriceps, and gastrocnemius muscles. Myostatin, IGF-I, IGF-II and proteasome 2c mRNA concentrations were determined by reverse transcription/PCR; myostatin and ubiquitin mRNA were also measured by Northern blot analysis; myostatin protein was estimated by immunohistochemistry; the apoptotic index and the release of 3-methylhistidine were determined respectively by the TUNEL assay and by HPLC. Muscle weights were 19-24% lower in the R1 rats compared with the control R3 and R5 rats, but were not significantly different after the recovery period. The myostatin/beta-actin mRNA ratios (means+/-s.e.m. ) were higher in the muscles of the R1 rats compared with the control R5 rats: 5.0-fold in tibialis (5.35 +/- 1.85 vs 1.07 +/- 0.26), 3.0-fold in biceps (2.46+/-0.70 vs 0.81 +/- 0.04), 1.9-fold in quadriceps (7.84 +/- 1.73 vs 4.08 +/- 0.52), and 2.2-fold in gastrocnemius (0.99 +/- 0.35 vs 0.44 +/- 0.17). These values also normalized upon acclimatization. Our antibody against a myostatin peptide was validated by detection of the recombinant human myostatin protein on Western blots, which also showed that myostatin immunostaining was increased in muscle sections from R1 rats, compared with control R3 rats, and normalized upon acclimatization. In contrast, IGF-II mRNA concentrations in the muscles from R1 rats were 64-89% lower than those in R3 animals. With the exception of the gastrocnemius, IGF-II was also decreased in R5 animals maintained in flight-simulated cages, and normalized upon acclimatization. The intramuscular IGF-I mRNA levels were not significantly different between the spaceflight rats and the controls. No increase was found in the proteolysis markers 3-methyl histidine, ubiquitin mRNA, and proteasome 2C mRNA. In conclusion, the loss of skeletal muscle mass that occurs during spaceflight is associated with increased myostatin mRNA and protein levels in the skeletal muscle, and a decrease in IGF-II mRNA levels. These alterations are normalized upon restoration of normal gravity and caging conditions. These data suggest that reciprocal changes in the expression of myostatin and IGF-II may contribute to the multifactorial pathophysiology of muscle atrophy that occurs during spaceflight.

scholarly journals Effects of the Aqueous Extract ofEremomastax speciosa(Acanthaceae) on Sexual Behavior in Normal Male Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
B. Nchegang ◽  
C. Mezui ◽  
F. Longo ◽  
Z. E. Nkwengoua ◽  
A. P. Amang ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Aqueous Extract ◽  
Male Rats ◽  
Normal Male ◽  
Adult Rats ◽  
Male Adult ◽  
Positive Effects ◽  
Posttreatment Period ◽  
And Performance ◽  
Behavior Of Rats

Objective. We studied prosexual effects ofEremomastax speciosaaqueous extract in male adult rats.Materials and Methods. 100 and 500 mg/kg of extract were administered orally (days 0, 1, 4, 7, 14, and 28 (posttreatment)). The sexual behavior of rats receiving a single dose (500 mg/kg) was also evaluated after pretreatment with Lω-NAME (10 mg/kg), haloperidol (1 mg/kg), or atropine (5 mg/kg). Controls received distilled water or testosterone enanthate (20 mg/kg/day/3 days(s.c.)before the test).Results. The extract (days 1–14) had no significant effect on mount, intromission, and ejaculation frequencies but on day 28 (14 days after treatment), it increased frequency of mounts and intromissions at 500 mg/kg. Mount, intromission, and ejaculation latencies reduced and postejaculatory intervals decreased but the effect did not persist 2 weeks after treatment. Extract prosex effects were greatly reduced by atropine and completely abolished by haloperidol, while Lω-NAME increased mount latency and potentiated extract effect on intromission and ejaculation latencies.Conclusion. In summary,E. speciosaextract can have positive effects on male sexual motivation and performance when administered for two weeks at the dose of 500 mg/kg. The effects (dopaminergic and/or cholinergic dependent) tend to appear during the posttreatment period.

scholarly journals Progestin increases the expression of gonadotropins in pituitaries of male zebrafish

2016 ◽  
Vol 230 (1) ◽  
pp. 143-156 ◽  
Author(s):  
Cuili Wang ◽  
Dongteng Liu ◽  
Weiting Chen ◽  
Wei Ge ◽  
Wanshu Hong ◽  
...  
Keyword(s):  
Time Course ◽  
Ex Vivo ◽  
Mrna Levels ◽  
Adult Zebrafish ◽  
Male Adult ◽  
Positive Effects ◽  
Time Course Experiment ◽  
Nuclear Progesterone Receptor

Our previous study showed that the in vivo positive effects of 17α,20β-dihydroxy-4-pregnen-3-one (DHP), the major progestin in zebrafish, on early spermatogenesis was much stronger than the ex vivo ones, which may suggest an effect of DHP on the expression of gonadotropins. In our present study, we first observed that fshb and lhb mRNA levels in the pituitary of male adult zebrafish were greatly inhibited by 3 weeks exposure to 10nM estradiol (E2). However, an additional 24h 100nM DHP exposure not only reversed the E2-induced inhibition, but also significantly increased the expression of fshb and lhb mRNA. These stimulatory effects were also observed in male adult fish without E2 pretreatment, and a time course experiment showed that it took 24h for fshb and 12h for lhb to respond significantly. Because these stimulatory activities were partially antagonized by a nuclear progesterone receptor (Pgr) antagonist mifepristone, we generated a Pgr-knockout (pgr–/–) model using the TALEN technique. With and without DHP in vivo treatment, fshb and lhb mRNA levels of pgr–/– were significantly lower than those of pgr+/+. Furthermore, ex vivo treatment of pituitary fragments of pgr–/– with DHP stimulated lhb, but not fshb mRNA expression. Results from double-colored fluorescent in situ hybridization showed that pgr mRNA was expressed only in fshb-expressing cells. Taken together, our results indicated that DHP participated in the regulation of neuroendocrine control of reproduction in male zebrafish, and exerted a Pgr-mediated direct stimulatory effect on fshb mRNA at pituitary level.

Reproductive toxicity and tissue concentrations of 3,3',4,4'-tetrachlorobiphenyl (PCB 77) in male adult rats

1998 ◽  
Vol 17 (3) ◽  
pp. 151-156 ◽  
Author(s):  
A S Faqi ◽  
P R Dalsenter ◽  
W Mathar ◽  
B Heinrich-Hirsch ◽  
I Chahoud
Keyword(s):  
Adult Male ◽  
Weight Control ◽  
Reproductive Toxicity ◽  
Serum Testosterone ◽  
Male Rats ◽  
Testis Weight ◽  
Adult Rats ◽  
Male Adult ◽  
Reproductive Effects ◽  
Investigation Period

1 The aim of this study was to ascertain the reproductive effects of PCB 77 on adult male rats and to determine its concentration in the liver and testis. Adult male rats (n=15/group) were treated subcutaneously with a singledoseof18 mg/kgbw(PC18)orwith60 mg/kg bw (PC60). The substance was dissolved in a 10 ml volume of peanut oil/kg. Control rats received the same volume of the vehicle. The reproductive effects as well as the concentration of PCB 77 in the liver and testis were investigated 1, 4 and 8 weeks after treatment. 2 In both groups, the daily sperm production (DSP; 6106) remained permanently reduced in the PC18 as well as in the PC60 groups throughout the entire investigation period (DSP week 8: control: 31+7; PC18: 22+5; PC60: 20+7). The sperm number (6106) per cauda epididymis was affected only at the 1st and 4th week after treatment (control week 1: 211+67; PC18 week 1: 135+62; PC60 week 1: 142+49). Moreover, a significant increase in the percentage of abnormal sperm was observed 4 weeks following treatment in the PC18 and PC60 groups and 8 weeks after treatment in the PC60 group. Abnormal tails were the most frequent changes observed. 3 The relative testicular and prostata weights (g) were slightly increased in the PC60 group at the 1st and 4th week following treatment (testis weight: control/I: 0.46+0.02; PC60/I: 0.51+0.03). 4 The serum testosterone concentrations and effects on testis morphology were not reported. 5 The maximum concentration of PCB 77 was detected in the liver and testis 1 week after treatment. The concentration declined 4 weeks after treatment in both organs, but still a significant amount of PCB 77 was detectable in the liver as well as in the testis 8 weeks after treatment. 6 The results demonstrate that PCB 77 affects sperm variables when applied to adult rats and that the elimination of PCB 77 in the testis parallels that of the liver.

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