Differential effects of the administration of human chorionic gonadotropin to postnatal rats

1994 ◽  
Vol 142 (3) ◽  
pp. 527-534 ◽  
Author(s):  
F Gaytan ◽  
L Pinilla ◽  
J L Romero ◽  
E Aguilar
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Leydig Cells ◽  
Reproductive Function ◽  
Male Rats ◽  
Testicular Development ◽  
Long Term Effects ◽  
Adult Type ◽  
Short And Long Term

Abstract Neonatal and prepubertal male rats were treated with human chorionic gonadotropin (hCG, 5 IU/g body weight per day) on days 2–4 or 20–22. Depending on the date of treatment, different groups of rats were sacrificed at 5, 23, 30 and 100 days of age, in order to study the short-and long-term effects of the treatment with hCG on the development of the testes and sex accessory organs. Rats treated with hCG on days 2–4 showed increased number and size of foetal Leydig cells at 5 days of age. However, long-term effects include decreased numbers of adult-type Leydig cells, decreased weight of the testes and sex accessory organs, decreased basal and hCG-stimulated testosterone secretion, and delayed balano-preputial separation. In contrast, animals treated with hCG on days 20–22 showed similar short- and long-term effects, consisting of increased number of adult-type Leydig cells and macrophages, increased weight of the testes and sex accessory organs and advanced balano-preputial separation. In adulthood, both groups showed normal reproductive function. These results seem to indicate that the effects of hCG treatment in prepubertal rats are dependent on the type of Leydig cell stimulated, and suggest that foetal Leydig cells play a regulatory role in the early postnatal testicular development. Journal of Endocrinology (1994) 142, 527–534

Testicular oxytocin: effects of intratesticular oxytocin in the rat

1991 ◽  
Vol 130 (2) ◽  
pp. 231-NP ◽  
Author(s):  
H. D. Nicholson ◽  
S. E. F. Guldenaar ◽  
G. J. Boer ◽  
B. T. Pickering
Keyword(s):  
Leydig Cells ◽  
Light And Electron Microscopy ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Epididymal Sperm ◽  
Long Term Effects ◽  
Sperm Counts ◽  
Term Administration

ABSTRACT The long-term effects of oxytocin administration on the testis were studied using intratesticular implants. Adult male rats had an Accurel device containing 20 μg oxytocin (releasing approximately 200 ng/day) implanted into the parenchyma of each testis; control animals received empty devices. The animals were killed at weekly intervals for 4 weeks. Some animals were perfused and the testes processed for light and electron microscopy. Blood was collected from the remaining animals for the measurement of testosterone, dihydrotestosterone, LH, FSH and oxytocin; epididymal sperm counts were measured and the testes were extracted and radioimmunoassayed for testosterone, dihydrotestosterone and oxytocin. Long-term administration of oxytocin resulted in a significant reduction in testicular and plasma testosterone levels throughout the 4-week period examined and, after 14 days of treatment, lipid droplets were seen in the Leydig cells of treated but not control animals. Concentrations of dihydrotestosterone in the plasma and testes of the oxytocin-treated animals, however, were significantly elevated after 7 and 14 days and at no time fell below control values. Plasma FSH levels were also lower in the oxytocin-treated animals. Intratesticular oxytocin treatment did not affect LH or oxytocin concentrations in the plasma, epididymal sperm counts or the number of Leydig cells in the testis. Empty Accurel devices had no effect on testicular morphology. This study provides the first evidence that oxytocin in vivo can modify steroidogenesis in the testis. Journal of Endocrinology (1991) 130, 231–238

Assessment of long-term effects of smoke from wildfires on white rats

2020 ◽  
Vol 60 (11) ◽  
pp. 720-722
Author(s):  
Elizaveta S. Andreeva
Keyword(s):  
Cognitive Abilities ◽  
Memory Performance ◽  
Recovery Period ◽  
White Male ◽  
Reproductive Function ◽  
Male Rats ◽  
Long Term Effects ◽  
Wildfire Smoke ◽  
White Rats

Introduction. The study of the effects of wildfire smoke on the reproductive function is the most important scientific problem at the present stage. The aim of study is to study the behavior and cognitive abilities of sexually mature offspring obtained from white male rats exposed to the smoke of wildfires. Materials and methods. Experiments were carried out on 30 white male rats and 60 adult male of their offspring. The duration of exposure was 4 weeks, 4 hours/day. To obtain progeny exposed males were mated with intact females immediately after the exposure and in long-term period after exposure. Examination of adult progeny was performed using the "open field", Morris water maze, and histological examination of brain tissue. Results. Behavioral and cognitive alterations in offspring of male rats exposed to wildfire smoke were obtained: significant decrease in motor activity and research on higher level of negative emotional state, impaired spatial memory performance. Individuals from offspring obtained in a long-term period after exposure to smoke showed a normalization of the studied parameters to background values. Conclusions. The long-term consequences of exposure to the smoke of wildfires were revealed, manifested in the offspring of the first generation in the form of impaired behavior and cognitive abilities. The recovery period after prolonged smoke intoxication, which is 60 days and is comparable in duration with the duration of spermatogenesis in rats, is important for reducing the risk of developing CNS disorders in offspring.

Bone and mineral metabolism in aged male rats: short and long term effects of androgen deficiency.

Endocrinology ◽  
1992 ◽  
Vol 130 (5) ◽  
pp. 2906-2916 ◽  
Author(s):  
D Vanderschueren ◽  
E Van Herck ◽  
A M Suiker ◽  
W J Visser ◽  
L P Schot ◽  
...  
Keyword(s):  
Mineral Metabolism ◽  
Male Rats ◽  
Androgen Deficiency ◽  
Long Term Effects ◽  
Short And Long Term

INCREASE IN THE LEVEL OF RETINAL MELATONIN AND PERSISTENCE OF ITS DIURNAL RHYTHM IN RATS AFTER PINEALECTOMY

1981 ◽  
Vol 91 (3) ◽  
pp. 477-481 ◽  
Author(s):  
H. S. YU ◽  
S. F. PANG ◽  
P. L. TANG
Keyword(s):  
Diurnal Rhythm ◽  
Feedback System ◽  
Male Rats ◽  
Long Term Effects ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Short And Long Term ◽  
Short Term Experiment ◽  
Compensatory Effect

To study the short- and long-term effects of pinealectomy on the level of retinal melatonin, male rats adapted to a photoperiod of 12 h light: 12 h darkness (with lights on at 06.00 h) were pinealectomized. In the short-term experiment, the rats were decapitated 1 week after pinealectomy. In the long-term experiment, 1 month was allowed for recovery. Melatonin was extracted from retinae and quantified by radioimmunoassay. A diurnal rhythm of retinal melatonin was found to persist after pinealectomy in both experiments. An increase in retinal melatonin was demonstrated 1 month after pinealectomy, indicating a compensatory effect on melatonin in the retinae of pinealectomized rats. Thus, biosynthesis of melatonin in the retina may be modulated through a negative feedback system.

scholarly journals Short- and long-term effects of (−)-epicatechin on myocardial ischemia-reperfusion injury

2008 ◽  
Vol 295 (2) ◽  
pp. H761-H767 ◽  
Author(s):  
Katrina Go Yamazaki ◽  
Diego Romero-Perez ◽  
Maraliz Barraza-Hidalgo ◽  
Michelle Cruz ◽  
Maria Rivas ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ischemia Reperfusion Injury ◽  
Tissue Injury ◽  
Ischemia Reperfusion ◽  
Male Rats ◽  
Myeloperoxidase Activity ◽  
Protective Effects ◽  
Long Term Effects ◽  
Short And Long Term

Epidemiological studies have shown a correlation between flavonoid-rich diets and improved cardiovascular prognosis. Cocoa contains large amounts of flavonoids, in particular flavanols (mostly catechins and epicatechins). Flavonoids possess pleiotropic properties that may confer protective effects to tissues during injury. We examined the ability of epicatechin to reduce short-and long-term ischemia-reperfusion (I/R) myocardial injury. Epicatechin (1 mg·kg−1·day−1) pretreatment (Tx) was administered daily via oral gavage to male rats for 2 or 10 days. Controls received water. Ischemia was induced via a 45-min coronary occlusion. Reperfusion was allowed until 48 h or 3 wk while Tx continued. We measured infarct (MI) size (%), hemodynamics, myeloperoxidase activity, tissue oxidative stress, and matrix metalloproteinase-9 (MMP-9) activity in 48-h groups. Cardiac morphometry was also evaluated in 3-wk groups. With 2 days of Tx, no reductions in MI size occurred. After 10 days, a significant ∼50% reduction in MI size occurred. Epicatechin rats demonstrated no significant changes in hemodynamics. Tissue oxidative stress was reduced significantly in the epicatechin group vs. controls. MMP-9 activity demonstrated limited increases in the infarct region with epicatechin. By 3 wk, a significant 32% reduction in infarct size was observed with Tx, accompanied with sustained hemodynamics and preserved chamber morphometry. In conclusion, epicatechin Tx confers cardioprotection in the setting of I/R injury. The effects are independent of changes in hemodynamics, are sustained over time, and are accompanied by reduced levels of indicators of tissue injury. Results warrant the evaluation of cocoa flavanols as possible therapeutic agents to limit ischemic injury.

Short- and long-term effects of testosterone on diaphragm in castrated and normal male rats

1997 ◽  
Vol 82 (1) ◽  
pp. 134-143 ◽  
Author(s):  
David J. Prezant ◽  
Manoj L. Karwa ◽  
Helen H. Kim ◽  
Diane Maggiore ◽  
Virginia Chung ◽  
...  
Keyword(s):  
Serum Testosterone ◽  
Male Rats ◽  
Normal Male ◽  
Type Ii ◽  
Long Term Effects ◽  
Testosterone Levels ◽  
Diaphragm Function ◽  
Short And Long Term ◽  
Normal Males

Prezant, David J., Manoj L. Karwa, Helen H. Kim, Diane Maggiore, Virginia Chung, and David E. Valentine. Short- and long-term effects of testosterone on diaphragm in castrated and normal male rats. J. Appl. Physiol. 82(1): 134–143, 1997.—The effects of short- and long-term testosterone absence or treatment on the diaphragm were studied in castrated and sexually normal male rats. Compared with control rats (untreated normal males), testosterone absence or treatment did not significantly affect costal weight. In untreated castrated males, there were significant decreases in specific forces, type II fiber cross-sectional area, and myosin heavy chain (MHC) isoform 2B after 2.5 wk. In castrated males that received testosterone, there were significant increases in specific forces, type II total fiber proportional area, and relative expression of all adult diaphragm fast MHC isoforms (MHC-2all) after 2.5 wk. In normal males that received testosterone, the only significant finding was an increase in MHC-2B after 2.5 wk. Across all groups, there was close correlation between increases in maximum tetanic forces and MHC-2all. Changes in diaphragm function and composition were closely related to changes in serum testosterone levels at 2.5 wk. The lack of significant change in diaphragm function at 10 wk occurred despite changes in serum testosterone levels and diaphragm composition similar to those at 2.5 wk. These findings support our hypothesis that the effects of testosterone are dependent on basal circulating androgen levels and study duration.

Saskatchewan Highways and Transportation Reduced Tire Pressure Initiative

1997 ◽  
Vol 1589 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Thomas L. Davies ◽  
Tami F. Wall ◽  
Allan Carpentier
Keyword(s):  
High Speed ◽  
Membrane Surface ◽  
Vehicle Stability ◽  
Road Maintenance ◽  
Long Term Effects ◽  
Tire Pressure ◽  
Reduced Pressure ◽  
Maintenance Costs ◽  
Short And Long Term

After examination of the research carried out by other agencies, Saskatchewan Highways and Transportation (SHT) embarked on an initiative to adapt low tire pressure technologies to the province's needs and environment. The focus of the initiative was to explore several technical questions from SHT's perspective: (a) Can low tire pressures be used to increase truck weights from secondary to primary without increasing road maintenance costs on thin membrane surface roads? (b) What are the short- and long-term effects of tire heating under high-speed/high-deflection constant reduced pressure (CRP) operations in a Saskatchewan environment? (c) What effects do lower tire pressures have on vehicle stability at highway speeds? To date, significant opportunities have been noted on local hauls (less than 30 min loaded at highway speeds) for CRP operation and long primary highway hauls that begin or end in relatively short secondary highway sections that limit vehicle weight allowed for the whole trip for central tire inflation technology. The background and environment for the initiative and the investigations and demonstrations envisioned and undertaken are briefly outlined.

Sign in / Sign up

Export Citation Format

Share Document