EFFECT OF NEONATAL ADMINISTRATION OF THYROXINE ON THE RATE OF SEBUM PRODUCTION IN RATS

1979 ◽  
Vol 83 (2) ◽  
pp. 199-203 ◽  
Author(s):  
YEE CHU TOH
Keyword(s):  
Normal Activity ◽  
Skin Surface ◽  
Postnatal Period ◽  
Female Rats ◽  
Sprague Dawley ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Sebum Production ◽  
Skin Surface Lipids ◽  
Neonatal Administration

Newborn Sprague–Dawley rats of both sexes were treated with 28 μg thyroxine (T4) daily for the first week of life. At the age of 80 days, the secretion rate of sebum was measured from the amount of skin-surface lipids extractable by acetone and which had been produced during 2 days. Treatment with such excess amounts of T4 during the early postnatal period significantly reduced the production of sebum in both male and female rats when compared with control rats and with rats deprived of food early in life. The thyroid, the pituitary gland, the testes and the seminal vesicles were significantly smaller but the weights of the ovaries and uteri remained relatively unaffected. There was a similar ratio of sex difference in the rate of sebum secretion irrespective of treatment. It is suggested that a reduction of sebaceous response in rats made thyrotoxic with large doses of T4 early in life was probably due to a decreased secretion of thyroid hormone which is required to maintain normal activity of the sebaceous glands.

ROLE OF THE GONADS IN THE REGULATION OF SEBACEOUS GLANDS IN RATS: COMPARISON OF THE EFFECTS OF CASTRATION AT AND AFTER BIRTH

1980 ◽  
Vol 85 (2) ◽  
pp. 261-265 ◽  
Author(s):  
YEE CHU TOH
Keyword(s):  
Skin Surface ◽  
Female Rats ◽  
Sprague Dawley ◽  
Sebaceous Glands ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Sequential Event ◽  
Sebum Production ◽  
Skin Surface Lipids

Sprague–Dawley rats were castrated either within 24 h of birth or at 4 weeks of age. Control animals were sham operated. Intact female rats were also included for comparison. Sebum production was assessed at 80 days of age by measuring the amount of skin-surface lipids that could be extracted with acetone and which had been produced during 2 days. The removal of the testes at birth reduced the activity of the sebaceous glands to a level more nearly approaching that seen in the female rats whereas castration at 4 weeks of age only partially decreased the rate of sebum secretion so that it was intermediate between the male and female rats. The weights of the pituitary gland, thyroid and adrenal glands increased after castration but there were no differences between rats castrated at birth and those castrated at 4 weeks of age except in the weight of the thyroid gland. It would appear that the role of the testes in the control of the activity of the sebaceous glands is a sequential event which has already started at birth.

scholarly journals A Safety Evaluation of a Nature-Identical l-Ergothioneine in Sprague Dawley Rats

2016 ◽  
Vol 35 (5) ◽  
pp. 568-583 ◽  
Author(s):  
Palma Ann Marone ◽  
Jan Trampota ◽  
Steven Weisman
Keyword(s):  
Body Weight ◽  
Body Weight Gain ◽  
Antioxidant Properties ◽  
Metabolic Activation ◽  
Female Rats ◽  
Systemic Absorption ◽  
Test Substance ◽  
Sprague Dawley ◽  
Male And Female Rats ◽  
Sprague Dawley Rats

l-(+) Ergothioneine is a naturally occurring thiol amino acid with antioxidant properties and potential benefits as a dietary supplement. Despite its century-old identification and wide distribution in human food, little is known of its mechanism of action and safety. The nature-identical biomimetic of l-(+) ergothioneine, produced by Mironova Labs and supplied as Mironova (EGT+), has been investigated in the present studies for its mutagenic and toxicologic potential. In a plate incorporation and preincubation assay with Salmonella typhimurium strains TA98, 100, 1,535, and 1,537 and Escherichia coli WP2uvrA strain, at dose concentrations of 1.58, 5, 15.8, 50, 158, 500, 1,580, and 5,000 μg/plate with and without metabolic activation, no cytotoxicity or mutagenicity was observed. Following a preliminary 28-day study, a repeated dose 90-day gavage study at dose levels of 0, 400, 800, and 1,600 mg/kg body weight (bw)/d in Sprague Dawley rats, in which dose-proportional systemic absorption was confirmed by plasma analysis, no adverse clinical, body weight/gain, food consumption and efficiency, clinical pathology, or histopathological changes associated with the administration of the nature-identical ergothioneine were observed. In conclusion, EGT+ administered over 90 days was well tolerated with a no adverse effect level at 1,600 mg/kg bw/d, the highest dose tested for male and female rats. In addition, the nature-identical test substance, EGT+ was not mutagenic in a bacterial reverse mutation assay at plate concentrations of up to 5,000 μg/mL in the presence or absence of metabolic activation.

scholarly journals Absorption, Distribution, Excretion, and Pharmacokinetics ofC-Pyronaridine Tetraphosphate in Male and Female Sprague-Dawley Rats

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Sang Hyun Park ◽  
Kannampalli Pradeep
Keyword(s):  
Clinical Trials ◽  
Small Intestine ◽  
Oral Administration ◽  
Female Rats ◽  
Sprague Dawley ◽  
Male And Female ◽  
Phase Ii Clinical Trials ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Peak Value

The main objective of this investigation was to determine the absorption, distribution, excretion, and pharmacokinetics of the antimalarial drug pyronaridine tetraphosphate (PNDP) in Sprague-Dawley rats. Following oral administration of a single dose (10 mg/Kg) ofC-PNDP, it was observed that the drug was readily absorbed from the small intestine within 1 hour following oral administration and was widely distributed in most of the tissues investigated as determined from the observed radioactivity in the tissues. The peak value of the drug in the blood was reached at around 8 hours postadministration, and radioactivity was detected in most of the tissues from 4 hours onwards.C-PNDP showed a poor permeability across the blood-brain barrier, and the absorption, distribution, and excretion ofC-PNDP were found to be gender-independent as both male and female rats showed a similar pattern of radioactivity. Excretion of the drug was predominantly through the urine with a peak excretion post 24 hours of administration. A small amount of the drug was also excreted in the feces and also in the breath. It was found that theCmax, AUC (0-inf), andTmaxvalues were similar to those observed in the Phase II clinical trials of pyronaridine/artesunate (Pyramax) conducted in Uganda.

scholarly journals Intraperitoneal Alfaxalone and Alfaxalone–Dexmedetomidine Anesthesia in Sprague–Dawley Rats (Rattus norvegicus)

2020 ◽  
Vol 59 (5) ◽  
pp. 531-538
Author(s):  
Sylvia E West ◽  
Jonathan C Lee ◽  
Tinika N Johns ◽  
Elizabeth A Nunamaker
Keyword(s):  
Rattus Norvegicus ◽  
Female Rats ◽  
Male Rats ◽  
Sprague Dawley ◽  
Male And Female ◽  
Withdrawal Reflex ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Laboratory Rodent ◽  
Physiologic Parameters

Due to their unpredictability and variable effects, injectable anesthetic regimens in laboratory rodent species warrant refinement. In our study we sought to evaluate alfaxalone, which has gained recent popularity in veterinary medicine, alone and in combination with dexmedetomidine to evaluate their anesthetic ability in Sprague–Dawley rats when administered intraperitoneally. Three doses of alfaxalone only and 4 dose combinations of alfaxalone-dexmedetomidine were tested in males and female rats. The time to induction, anesthetic duration, pulse rate, respiratory rate, temperature, and time to recovery were recorded by a blind observer. The level of anesthesia induced by the various anesthetic protocols was assessed by using pedal withdrawal reflex to a noxious stimulus and scored according to the response. Dependent on the treatment group, atipamezole or saline was administered intraperitoneally once animals reached 60 min of anesthesia. Regardless of the dose, alfaxalone alone achieved only a sedative level of anesthesia, whereas all alfaxalone-dexmedetomidine combinations led to a surgical level of anesthesia in all animals. Anesthesia regimens using alfaxalone alone and in combination with dexmedetomidine demonstrated sex-associated differences, with female rats maintaining longer durations of sedation or anesthesia than their male counterparts. Both male and female rats displayed decreases in physiologic parameters consistent with the effects of dexmedetomidine. Given the results described herein, we recommend 20 mg/kg alfaxalone for sedation and 30 mg/kg alfaxalone combined with 0.05 mg/kg dexmedetomidine for surgical anesthesia in female rats. Appropriate doses of alfaxalone only and alfaxalone-dexmedetomidine for male rats were not determined in this study and need further evaluation.

Abstract 386: Compound 21 Induces Natriuresis via Renal AT2 Receptor Activation in Male and Female Rats

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Brandon A Kemp ◽  
Nancy L Howell ◽  
Robert M Carey
Keyword(s):  
Receptor Activation ◽  
Female Rats ◽  
Male Rats ◽  
Sprague Dawley ◽  
Male And Female ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Angiotensin Iii ◽  
Compound 21 ◽  
Renal Cortical Interstitium

Endogenous renal des-aspartyl 1 -angiotensin II (angiotensin III) activates renal proximal tubule AT 2 receptors (AT 2 Rs) and induces natriuresis via a nitric oxide-cyclic GMP signaling pathway. The present study explores the ability of highly selective non-peptide AT 2 R agonist Compound 21 (C21) to induce natriuresis. Sprague-Dawley rats (12 weeks old; male N=22; female N=18) were studied in the presence and absence of concurrent 24-h AT 1 R blockade with candesartan (CAND;0.01 mg/kg/min). Rats were anesthetized with Inactin 100 mg/kg i.p., uninephrectomized and instrumented for delivery of 3 cumulative 30-min i.v. infusions of C21 (100, 200, and 300 ng/kg/min) following a 30-min control infusion of vehicle. Mean arterial pressure (MAP) was measured for all periods and urine Na + excretion rate (U Na V) was calculated for the control and final C21 collection periods. To determine whether the systemically induced natriuresis is mediated by renal AT 2 Rs, PD-123319 (PD), a specific AT 2 R antagonist, was infused directly into the renal cortical interstitium(20 μg/kg/min and 10 μg/kg/min for females and males, respectively) during the i.v. C21 infusions. In female rats, C21 increased U Na V from 1.5 ± 0.20 to 7.48 ± 0.95 μmol/min (P<0.0001). This response was abrogated by concurrent intrarenal PD infusion [control 0.74 ± 0.19 vs. C21 2.02 ± 0.50 μmol/min (P<0.001from C21 alone). Systemic CAND administration augmented the natriuretic response to C21 [control 1.29 ± 0.25 vs. C21 10.68 ± 0.70 μmol/min (P<0.05 from C21 alone)]. In male rats, C21 increased U Na V from 0.46 ±0.08 to 6.21 ± 1.33 μmol/min (P<0.01). This response was blocked by concurrent intrarenal PD infusion [control 0.39 ± 0.11 vs. C21 1.69 ± 0.53 μmol/min (P<0.05 from C21 alone). Systemic CAND did not significantly alter the natriuretic response to C21 alone [control 0.49 ± 0.15 vs. C21 7.67 ± 0.72 μmol/min (P = NS from C21 alone). In female rats, CAND augmented the natriuretic response to C21 over that of male rats (P<0.01). Systemic arterial pressures were decreased by CAND in both male and female rats but were unchanged by C21 alone or together with intrarenal PD. C21 induces natriuresis via renal AT 2 R activation in both male and female rats. These data suggest the potential for AT 2 R agonist therapy in hypertension.

Maximum oxygen consumption of rats and its changes with various experimental procedures

1979 ◽  
Vol 47 (6) ◽  
pp. 1278-1283 ◽  
Author(s):  
T. G. Bedford ◽  
C. M. Tipton ◽  
N. C. Wilson ◽  
R. A. Oppliger ◽  
C. V. Gisolfi
Keyword(s):  
Test Procedure ◽  
Repeated Measurements ◽  
Female Rats ◽  
Shr Rats ◽  
Sprague Dawley ◽  
Cross Sectional ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Wistar Kyoto ◽  
Different Strains

A ten-stage treadmill test was developed and standardized to secure the VO2max of male and female rats assigned to various cross-sectional and longitudinal experimental groups. Repeated measurements indicated that the test procedure was reliable and could be used for research purposes. When the test was used with different strains, the untrained Sprague-Dawley rats had significantly higher VO2max values than animals of the Wistar-Kyoto (WKY) or the Okamoto-Aoki (SHR) strains. Exercise schedules were evaluated that were similar to those previously used by various investigators and it was found that most were exercising their rats at levels exceeding 75% VO2max. After 6--10 wk of chronic exercise, significant increases in VO2max occurred that ranged between 12 and 26%. Longitudinal studies (1 yr) with hypertensive (SHR) rats revealed that it was more desirable to logarithmically evaluate the relationship between VO2max and body mass than by the conventional method of ml . kg-1 . min-1. When this approach was used with SHR animals, the VO2max differences between the sexes were not apparent until the animals were 1 yr of age. On the other hand, training by male SHR rats caused significant increases in VO2max regardless of the method used to express the results. It is recommended that future studies designed to elucidate exercise mechanisms in rats should include a standardized VO2max test.

Influences of chemical sympathectomy and simulated weightlessness on male and female rats

1991 ◽  
Vol 71 (3) ◽  
pp. 1005-1014 ◽  
Author(s):  
C. R. Woodman ◽  
C. S. Stump ◽  
J. A. Stump ◽  
L. A. Sebastian ◽  
Z. Rahman ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Mechanical Efficiency ◽  
Female Rats ◽  
Plasma Norepinephrine ◽  
Chemical Sympathectomy ◽  
Simulated Weightlessness ◽  
Sprague Dawley ◽  
Male And Female ◽  
Male And Female Rats ◽  
Sprague Dawley Rats

Maximum oxygen consumption (VO2max) has been shown to be reduced after periods of simulated weightlessness. To assess the role of the sympathetic nervous system in these reductions, Sprague-Dawley rats were either chemically sympathectomized (SYMX) or injected with saline (SHAM) and assigned to head-down suspension (HDS), horizontal restraint with the hindlimbs weight bearing (HWB), or cage-control (CC) conditions. VO2max, run time (RT), and mechanical efficiency (ME) were measured before suspension and on days 7 and 14. Male and female SHAM HDS groups exhibited reduced measures of VO2max (12–13%) after 7 and 14 days, and this decrease was attenuated in the SYMX and HWB rats. HDS resulted in a significant reduction in RT (9–15%) in both the male and female rats, and ME was significantly reduced after HDS in male and female SYMX and male SHAM rats (23–33%) but not in the female SHAM rats. Lesser reductions in ME were observed in the HWB rats. HDS and HWB were associated with lower body, fat-free, and fat masses, which were similar in male and female rats as well as for the SHAM and SYMX conditions. In a related HDS experiment with normal rats, plasma norepinephrine and epinephrine were increased by 53 and 42% after 7 days, but only epinephrine returned to baseline after 14 days. It was concluded that chemical sympathectomy and/or a weight-bearing stimulus will attenuate the loss in VO2max associated with simulated weightlessness in rats despite similar changes in body mass and composition. The mechanism(s) remains unclear at this time.

scholarly journals Subchronic toxicity of lyophilized apoaequorin protein powder in Sprague-Dawley rats

2018 ◽  
Vol 2 ◽  
pp. 239784731875690
Author(s):  
Mark R. Bauter ◽  
Odete Mendes
Keyword(s):  
Active Ingredient ◽  
Calcium Binding ◽  
Clinical Pathology ◽  
Female Rats ◽  
Test Substance ◽  
Sprague Dawley ◽  
Oral Gavage ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Dose Levels

Apoaequorin is a bioluminescent calcium-binding apoprotein endogenous to the Aequorea species of jellyfish and is commercially available in a dietary supplement in support of brain and cognitive health. Results from a previous 90-day subchronic oral gavage study established the no-observed-adverse-effect-level (NOAEL) of lyophilized apoaequorin protein powder (LAPP) at 666.7 mg/kg/day. The current 90-day oral gavage study in Sprague-Dawley rats administered dose levels of 1000, 2000, and 4000 mg/kg/day of test substance as received. These doses are expressed as milligram of supplement with the amounts of apoaequorin based on the analysis of the percentage of active ingredient. The corresponding amounts of apoaequorin protein are 603, 1206, and 2412 mg/kg/day. These dose levels target approximately 4221, 8442, and 16,844 times more than the expected human oral intake. There were no mortalities, clinical observations, ophthalmological, clinical pathology, or histopathological changes attributable to LAPP administration. Changes in mean body weight and feed efficiency, without other correlating clinical or pathological or other toxicologically relevant findings, were considered to be of little toxicological significance. Therefore, the NOAEL for LAPP administered orally up to 90 days was 4000 mg/kg/day (2412 mg/kg/day based on 603 mg/g or 60.3% active ingredient, apoaequorin protein), the highest dose tested in male and female rats.

Toxic Peripheral Neuropathy with Demyelination in Sprague-Dawley Rats Given CGS 21595 —A 5-Lipoxygenase Inhibitor

1992 ◽  
Vol 29 (2) ◽  
pp. 145-151 ◽  
Author(s):  
D. E. Gunson ◽  
P. S. Sahota ◽  
W. O. Iverson ◽  
R. Y. Chau ◽  
G. M. McCormick ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Recovery Period ◽  
Female Rats ◽  
Male Rats ◽  
Renal Tubules ◽  
Sprague Dawley ◽  
Lipoxygenase Inhibitor ◽  
Male And Female ◽  
Male And Female Rats ◽  
Sprague Dawley Rats

Male and female Sprague-Dawley rats were given CGS 21595, a pro-drug that is almost immediately metabolized to CGS 19213, a naphthoquinone that acts as a 5-lipoxygenase inhibitor. The compound was administered by gavage to five groups of Sprague-Dawley rats (group Nos. 1, 5, n = 30; group Nos. 2–4, n = 20) at daily doses of 0, 50, 150, 500, or 1,000 mg/kg for 13 weeks. Rats in the higher dose groups had a reduced weight gain, but significant neurologic signs were not observed. A peripheral neuropathy consisting predominantly of myelin destruction in the spinal nerve roots and sciatic nerves was seen in male rats treated with ≥ 150 mg/kg CGS 21595 and in female rats treated with ≥50 mg/kg CGS 21595 for 13 weeks. This lesion was not fully reversible after a recovery period of 4 weeks. Lesions consisted of ballooning of myelin sheaths, infiltration by macrophages, demyelination, and occasional areas of remyelination. Axons were generally preserved, and the brain and spinal cord were not affected. Male and female rats in all treatment groups had cytoplasmic hyaline droplets in the proximal renal tubules. This change was reversible after 4 weeks and was not associated with any other adverse effects on the kidney.

Toxicology of Diethylene Glycol Butyl Ether 5. Dermal Subchronic Neurotoxicity Study in Rats

1993 ◽  
Vol 12 (2) ◽  
pp. 169-174 ◽  
Author(s):  
P. Beyrouty ◽  
B. Broxup ◽  
G. Losos ◽  
K. Robinson ◽  
J. P.J. Maurissen ◽  
...  
Keyword(s):  
Motor Activity ◽  
Diethylene Glycol ◽  
Dose Group ◽  
Clinical Findings ◽  
The Body ◽  
Female Rats ◽  
Sprague Dawley ◽  
Butyl Ether ◽  
Male And Female Rats ◽  
Sprague Dawley Rats

Groups of Sprague-Dawley rats were treated dermally with the vehicle, distilled water or with diethylene glycol butyl ether (DGBE) at 10 or 30% v/v aq. solutions or undiluted (0.2, 0.6, or 2.0 g/kg body weight) for 13 weeks under occlusion 6 hr/day, 5 days/week, at the maximum attainable volume of 2 mL/kg. Male and female rats were examined using a functional observational battery (FOB) prestudy, at 1, 6, and 24 hr after the initiation of the first exposure, and prior to treatment on days 7, 14, 35, 63, and 91. Motor activity was determined prestudy and on nontreated days 34, 62, and 90. At the completion of treatment, six control and top dose group animals were perfused for neuropathology. There was no mortality, and the body weights and food consumption were unaffected. Five females in the top dose group had scab formation at the treatment site during the study. There were no other treatment-related clinical findings. The FOB and motor activity tests revealed no findings indicative of a neurotoxic effect, and there were no gross or neuropathological changes that were attributed to treatment. No neurotoxicity or other systemic toxicity was seen at the highest dose tested—2 g/kg/day.

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