A QUANTITATIVE STUDY ON FEEDBACK CONTROL OF LH BY TESTOSTERONE IN YOUNG ADULT AND OLD MALE RATS

1978 ◽  
Vol 89 (4) ◽  
pp. 789-795 ◽  
Author(s):  
Karl M. Pirke ◽  
Michael Geiss ◽  
Rainer Sintermann
Keyword(s):  
Young Adult ◽  
Feedback Control ◽  
Quantitative Study ◽  
Wistar Rats ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Male Wistar Rats ◽  
Old Rats ◽  
Lh Secretion

ABSTRACT The hypothalamic-pituitary gonadal axis was studied in young adult (3 month old) and old (24 to 27 month old) male Wistar rats. Plasma testosterone decreased significantly in old animals (x̄: 262 ng/100 ml (n = 35); versus x̄: 110 ng/100 ml (n = 30)). The fall in LH was less pronounced but still significant (54.5 ng LH-RP-1/ml in young versus 39.5 ng/ml in old rats). Groups of 6 to 8 animals of both ages were castrated and implanted with silastic capsules continuously releasing testosterone. The length of the capsules was directly proportional to the plasma testosterone levels achieved (range between 63 and 350 ng/100 ml). After one week young castrated rats not substituted with testosterone showed LH values three times higher (x̄: 351 ng/ml) than old rats treated in the same way (x̄ = 126 ng/ml). LH values in the animals substituted with testosterone indicate that the sensitivity of the negative testosterone-LH feedback is greatly increased in old rats. Testosterone can be depressed to 60 ng/100 ml before an increase in LH occurs. In young rats no increase in LH was observed when testosterone values were higher than 170 ng/100 ml. In the range between 170 and 100 ng/100 ml about half of the young animals reacted with increased LH secretion, while an increase was observed in all young animals when testosterone dropped below 100 ng/100 ml.

scholarly journals ANTIFERTILITY ACTIVITY OF DECASCHISTIA CROTONIFOLIA LEAF EXTRACT ON MALE RATS

2019 ◽  
pp. 190-192
Author(s):  
AFSAR SHAIK ◽  
PRASANNA RAJU YALAVARTHI ◽  
CHANDRASEKHAR KOTHAPALLI BONNOTH
Keyword(s):  
Plant Extract ◽  
Normal Saline ◽  
Wistar Rats ◽  
Leaf Extract ◽  
Sperm Count ◽  
Male Rats ◽  
Testosterone Levels ◽  
Group I ◽  
Male Wistar Rats ◽  
Dose Dependent

Objective: The objective was to investigate the male antifertility effect of Decaschistia crotonifolia leaf extract on male Wistar rats. Methods: The animals were divided into three groups of five animals each. The first group (I) served as control and received normal saline, and remaining Groups II and III were treated with plant extract at a dose of 200 and 400 mg/kg p.o., respectively, for 21 days. Results: Dose-dependent significant decrease in the weight of testes and epididymis was observed. Furthermore, a dose-related reduction in sperm count and motility was observed. A significant decrease in testosterone levels leading to infertility was also observed. Conclusion: The 70% methanolic leaf extract of D. crotonifolia has produced dose-dependent antifertility effect on male rats.

Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat

1981 ◽  
Vol 96 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Mridula Chowdhury ◽  
Robert Tcholakian ◽  
Emil Steinberger
Keyword(s):  
Treated Group ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Control Group ◽  
Intact Male ◽  
Intact Control ◽  
Testosterone Levels ◽  
Oestradiol Benzoate ◽  
Direct Inhibitory Effect

Abstract. It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 μg of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.

scholarly journals Upregulation of Kiss-1 and Gpr54 Genes Expression in Pituitary of Male Rats Following the Central Administration of Neuropeptide Y

2019 ◽  
Vol 4 (4) ◽  
pp. 137-142
Author(s):  
Vahid Azizi ◽  
Shahrbanoo Oryan ◽  
Homayuon Khazali ◽  
Abdolkarim Hosseini
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Neuropeptide Y ◽  
Wistar Rats ◽  
Third Ventricle ◽  
Male Rats ◽  
Control Group ◽  
Central Administration ◽  
Reproductive Axis ◽  
Male Wistar Rats

Introduction: The neuropeptide Y (NPY) in the neural circuits of the hypothalamus has a stimulating effect on reproductive activities in mammals. Kisspeptin (KiSS1) is a quintessential neurotransmitter in the reproductive axis which directly stimulates gonadotropin-releasing hormone neurons in the hypothalamus. The distribution of KiSS1 expressing cells in the pituitary was described previously. Despite earlier reports showing the KiSS1 receptor, G-protein coupled receptor 54 (GPR54) expression in the pituitary, the potential physiological roles of kisspeptin at this gland have remained obscure. Accordingly, this study investigated the role of NPY on the relative expression of Kiss1 and Gpr54 genes in the pituitary gland in male Wistar rats. Methods: In general, 20 male Wistar rats weighing 200-250 g in 4 groups (5 in each group) received saline, NPY (2.3 nM), BIBP3226 (NPY receptor antagonist, 7.8 nM), and NPY+ BIBP3226. Then, they received the simultaneous injection of these molecules through the third ventricle of the brain. Finally, the relative mean expressions of Kiss1 and Gpr54 genes in the anterior pituitary were quantitatively analyzed by the real-time polymerase chain reaction. Results: The central injection of NPY increased the relative mean expressions of Kiss1 and Gpr54 genes in the pituitary gland compared to the control group although the injection of BIBP3226 eradicated these effects. However, the gene expression of Gpr54 in the rats receiving NPY coupled with BIBP3226 in hypophysis in comparison to the group receiving only NPY demonstrated a significant reduction (P<0.05). Conclusion: Overall, the central injection of NPY stimulated the gene expression of Kiss1 and Gpr54 in the pituitary gland.

SHORT-TERM EFFECTS OF COPULATION, HUMAN CHORIONIC GONADOTROPHIN INJECTION AND NON-TACTILE ASSOCIATION WITH A FEMALE ON TESTOSTERONE LEVELS IN THE MALE RAT

1974 ◽  
Vol 60 (3) ◽  
pp. 429-439 ◽  
Author(s):  
K. PURVIS ◽  
N. B. HAYNES
Keyword(s):  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Physical Contact ◽  
Male Rats ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Short Term ◽  
Testosterone Levels ◽  
Peripheral Plasma ◽  
First Contact

SUMMARY Peripheral plasma testosterone levels in the male rat were increased above control levels 5 min after the first intromission with an oestrous female, or 8–10 min after first contact with the female. The levels remained raised for at least 30 min if copulation was allowed to continue. Intravenous injection of human chorionic gonadotrophin resulted in an increased peripheral concentration of plasma testosterone after 10–15 min and an increase of testosterone content of the testis 5–10 min after injection, indicating that the rat testis has a potential to respond rapidly to gonadotrophin. The results suggested that if the testosterone surge during copulation was gonadotrophin-dependent, it was initiated before the first intromission. Indeed, plasma testosterone levels were raised in male rats 5 min after being placed in the proximity of oestrous females but not allowed physical contact.

Fluctuations in Plasma Testosterone Levels in Adult Male Rats and Mice

Endocrinology ◽  
1973 ◽  
Vol 92 (4) ◽  
pp. 1223-1228 ◽  
Author(s):  
A. BARTKE ◽  
R.E. STEELE ◽  
N. MUSTO ◽  
B.V. CALDWELL
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Rats And Mice

Hypothalamic paraventricular nucleus lesions do not prevent anorectic effect of exercise in male rats

1990 ◽  
Vol 259 (3) ◽  
pp. R579-R584 ◽  
Author(s):  
S. Rivest ◽  
D. Richard
Keyword(s):  
Body Weight ◽  
Energy Balance ◽  
Paraventricular Nucleus ◽  
Wistar Rats ◽  
Energy Gain ◽  
Hypothalamic Paraventricular Nucleus ◽  
Male Rats ◽  
Hypothalamic Nucleus ◽  
Serum Corticosterone ◽  
Male Wistar Rats

The effects of a hypothalamic paraventricular nucleus (PVN) lesion on energy balance were investigated in exercise-trained rats. Male Wistar rats weighing initially 250 g were divided into four groups. Two groups of rats underwent a bilateral PVN lesion, whereas the two remaining groups were sham operated. The PVN lesions were done electrolytically. One group from each surgical treatment was exercised, while the other group was kept in sedentary conditions. Rats were exercised on a rodent motor-driven treadmill at moderate intensity, 1 h/day for 21 consecutive days. Food intake and body weight were measured each day during the study. At the end of the treatment period, rats were killed, and carcasses were analyzed for their energy content. Serum corticosterone was measured by a competitive protein-binding assay. Energy gain and energy intake were lower in exercised rats than in sedentary controls, regardless of whether they were sham or PVN lesioned. Concurrently, there was no difference in the energy gain between PVN-lesioned and sham-operated rats, despite the fact that PVN-lesioned rats ended the experiment with a larger body weight than the sham-lesioned animals. Serum corticosterone levels were lower in PVN-lesioned rats than in sham-lesioned rats. In conclusion, the present results indicate that the PVN, the hypothalamic nucleus predominantly controlling the pituitary-adrenal axis activity, is not a prominent structure in the regulation of energy balance in exercised male Wistar rats.

scholarly journals Cell-Free DNA Plasma Levels Differ in Age-Specific Pattern in Healthy Rats and Castrates with Testosterone-Induced Benign Prostatic Hyperplasia

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
I. N. Vasilyeva ◽  
V. G. Bespalov ◽  
J. D. Von ◽  
A. L. Semenov ◽  
G. V. Tochilnikov ◽  
...  
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Wistar Rats ◽  
Specific Pattern ◽  
Prostatic Hyperplasia ◽  
The Body ◽  
Cell Free Dna ◽  
Young Rats ◽  
Free Dna ◽  
Male Wistar Rats ◽  
Old Rats

The purpose of this work was to study changes in the level of cell-free DNA (cfDNA) in the blood of young and old rats in the normal state and with induced benign prostatic hyperplasia (BPH). Male Wistar rats were divided into 4 groups—young (3 months), old (20 months), intact, or with testosterone-induced BPH. Groups with BPH were subjected to surgical castration and administration of testosterone esters at a dose of 25 mg/kg for a total of 7 injections for 20 days. In intact animals, the level of cfDNA in old rats (2.00±0.14 ng/μl) was significantly higher than that in the young (1.02±0.30 ng/μl). The body and the prostate weights of old rats were 1.6 and 1.4 times larger than those of the young, without an increase in the prostate index (PI). The testosterone level in the blood of young rats was 1.6 times higher than that of old (6.20±0.93 nmol/l vs. 3.77±0.55 nmol/l; NS). In animals with BPH, the level of cfDNA in old rats (3.14±0.76 ng/μl) was significantly higher than that in young rats (0.80±0.14 ng/μl). The body and the prostate weights in old rats were 1.8 and 2.3 times larger, than those in young rats, with an increase in the PI. The level of testosterone in the blood of young (15.76±0.51 nmol/l) and old (16.99±1.1 nmol/l) rats was not significantly different. Morphological signs of BPH were observed in the prostate of both young and old rats. During the induction of BPH in the experiment, according to the level of cfDNA, cell death processes have not changed significantly in young rats but significantly increased in old rats. A similar trend was observed in the group of intact animals. The obtained data indicate that apoptosis processes are enhanced during the development of BPH despite the growth of tissues in the prostate itself.

scholarly journals Commercial Formulation of Chlorpyrifos Alters Neurological Behaviors and Fertility

Biology ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Enoka P. Kudavidanage ◽  
D. M. I. Dissanayake ◽  
W. L. Rangi Keerthirathna ◽  
N. Lasni Wathima Nishshanke ◽  
L. Dinithi C. Peiris
Keyword(s):  
Wistar Rats ◽  
Serum Testosterone ◽  
Female Rats ◽  
Male Rats ◽  
Risk Minimization ◽  
Commercial Formulation ◽  
Male Wistar Rats ◽  
Neurological Alterations ◽  
Implantation Sites ◽  
Androgen Levels

Pesticides are known to result in toxic insult. We aimed to evaluate Judo 40, the commercial formulation of chlorpyrifos on the neurological activities, fertility, and hormone levels of male rats. Male Wistar rats were treated orally with 1 mL of 20 or 50 mg/kg Judo 40. The doses were administered four times, twice a day. Sexual and exploratory behavior indices, fertility indices, serum androgen levels, blood acetylcholinesterase (BChE) levels, and neurological and muscular effects were evaluated. Serum testosterone and luteinizing hormone were significantly reduced in the rats receiving 50 mg/kg Judo 40. A reduction in viable implantation sites and live pups born were evident in the female rats mated with the male rats treated with the highest dose. Similarly, in the rats treated with the highest dose of Judo 40, a significant reduction in plasma BChE enzyme was observed. According to the results, prolonged Judo 40 exposure can cause impairment of the neurological alterations and sex hormones leading to impaired fertility. Therefore, chemical handlers should be educated on protection and risk minimization.

EFFECTS OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE ON PLASMA TESTOSTERONE LEVELS IN HYPOPHYSECTOMIZED AND IN INTACT IMMATURE AND ADULT MALE RATS

1974 ◽  
Vol 61 (2) ◽  
pp. 193-198 ◽  
Author(s):  
S. EL SAFOURY ◽  
A. BARTKE
Keyword(s):  
Luteinizing Hormone ◽  
Adult Male ◽  
Follicle Stimulating Hormone ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Adult Rats ◽  
Testosterone Levels ◽  
Hypophysectomized Rats ◽  
Stimulating Hormone

SUMMARY The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on plasma testosterone levels were examined in hypophysectomized and in intact immature and adult male rats. The animals were injected with saline, LH, FSH, or both gonadotrophins twice daily for 3·5 days and were killed 3 h after the last injection. Plasma testosterone levels were measured by radioimmunoassay. In immature hypophysectomized rats, plasma testosterone levels were not changed by treatment with LH, FSH or LH plus FSH. The weight of the testes and of the seminal vesicles was increased only in animals injected with both LH and FSH. In adult hypophysectomized rats, LH caused the expected increase in plasma testosterone levels, while FSH injected alone had no effect. Plasma testosterone levels in rats treated with 5 μg LH and 20 μg FSH were significantly greater than those in animals given 5 μg LH alone. However, the same dose of FSH did not potentiate the action of 25 μg LH on plasma testosterone levels. In adult hypophysectomized rats the weight of testes was not affected by any of the treatments. The weight of the seminal vesicles was increased by the higher dose of LH and addition of FSH caused no further increase. In intact immature and adult rats plasma testosterone levels and the weight of testes were not changed by any of the treatments. Seminal vesicle weight was increased only in adult rats treated with the higher dose of LH together with FSH. The results demonstrate that FSH potentiates the action of low doses of LH on plasma testosterone levels in adult hypophysectomized rats and suggest that FSH may be involved in the regulation of androgen secretion by the rat testis.

scholarly journals Sudden decrease in physical activity evokes adipocyte hyperplasia in 70- to 77-day-old rats but not 49- to 56-day-old rats

2013 ◽  
Vol 305 (12) ◽  
pp. R1465-R1478 ◽  
Author(s):  
Joseph M. Company ◽  
Michael D. Roberts ◽  
Ryan G. Toedebusch ◽  
Clayton L. Cruthirds ◽  
Frank W. Booth
Keyword(s):  
Physical Activity ◽  
Adipose Tissue ◽  
Wistar Rats ◽  
Percent Body Fat ◽  
Voluntary Running ◽  
Male Wistar Rats ◽  
Old Rats ◽  
Sudden Decrease ◽  
Tissue Characteristics ◽  
Adipocyte Hyperplasia

The cessation of physical activity in rodents and humans initiates obesogenic mechanisms. The overall purpose of the current study was to determine how the cessation of daily physical activity in rats at 49–56 days of age and at 70–77 days of age via wheel lock (WL) affects adipose tissue characteristics. Male Wistar rats began voluntary running at 28 days old and were either killed at 49–56 days old or at 70–77 days old. Two cohorts of rats always had wheel access (RUN), a second two cohorts of rats had wheel access restricted during the last 7 days (7d-WL), and a third two cohorts of rats did not have access to a voluntary running wheel after the first 6 days of (SED). We observed more robust changes with WL in the 70- to 77-day-old rats. Compared with RUN rats, 7d-WL rats exhibited greater rates of gain in fat mass and percent body fat, increased adipocyte number, higher percentage of small adipocytes, and greater cyclin A1 mRNA in epididymal and perirenal adipose tissue. In contrast, 49- to 56-day-old rats had no change in most of the same characteristics. There was no increase in inflammatory mRNA expression in either cohort with WL. These findings suggest that adipose tissue in 70- to 77-day-old rats is more protected from WL than 49- to 56-day-old rats and responds by expansion via hyperplasia.

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