A high dose of short term exogenous d-galactose administration in young male rats produces symptoms simulating the natural aging process

Life Sciences ◽  
2015 ◽  
Vol 124 ◽  
pp. 110-119 ◽  
Author(s):  
Saida Haider ◽  
Laraib Liaquat ◽  
Sidrah Shahzad ◽  
Sadia Sadir ◽  
Syeda Madiha ◽  
...  
Keyword(s):  
Aging Process ◽  
Natural Aging ◽  
Young Male ◽  
Male Rats ◽  
High Dose ◽  
Short Term

1,1,1,3,3,3-Hexamethyldisilazane (2018)

2019 ◽  
Vol 35 (3) ◽  
pp. 189-195
Keyword(s):  
Inhalation Exposure ◽  
Male Rats ◽  
Feed Consumption ◽  
High Dose ◽  
Exposure Level ◽  
Short Term ◽  
Adhesion Promoter ◽  
Inhalation Study ◽  
Short Term Exposure ◽  
Dose Inhalation

1,1,1,3,3,3-Hexamethyldisilazane (HMDZ) is used industrially to treat the surface of silica, as an intermediate adhesion promoter or silylating agent in the semiconductor industry, as a chemical modifier of inorganic fillers, and as a water scavenger silicone sealant. In animal studies, HMDZ is considered to be slightly to at most moderately toxic following acute administration via oral, dermal, and inhalation routes of exposure. HMDZ is neither an eye irritant nor was it dermally irritating under semiocclusive conditions; however, it caused dermal necrosis in two studies under occlusive conditions. HDMZ is not genotoxic or mutagenic in in vitro assays and was not reproductively or developmentally toxic in an inhalation screening study in rats. Short-term and subacute, high-dose inhalation exposure to HMDZ produced respiratory tract irritation, reduced feed consumption, changes in clinical chemistry parameters, and reversible central nervous system depression in rats. In a 90-day inhalation exposure study in rats, HMDZ exposure-related effects were observed in the kidneys of male rats but were determined to be alpha-2µ-nephropathy, thus, not relevant to humans. Based on the results of the 90-day (subchronic) inhalation study, 75 ppm was determined to be the no-observed adverse effect level (NOAEL) and was selected as the point of departure for the derivation of the 8-h time-weighted average (TWA), health-based workplace environmental exposure level (WEEL) value. This subchronic inhalation NOAEL was adjusted to account for duration of exposure, interindividual variability, and intraindividual variability. The resulting 8-h TWA WEEL value of 10 ppm is fully expected to provide a significant margin of safety against any potential adverse health effects in workers following long-term inhalation exposure to HMDZ vapor. A 15-min short-term exposure limit of 50 ppm was also established to protect workers from reversible effects produced by acute, high-dose inhalation of HMDZ vapor. A skin notation (Skin) is warranted because of the potential for the dermal route to significantly contribute to the overall exposure to HMDZ.

scholarly journals Effect of Short-Term Fasting on Bone Elongation Rates: An Analysis of Catch-up Growth in Young Male Rats

2003 ◽  
Vol 53 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Cornelia E Farnum ◽  
Andrea O Lee ◽  
Kathleen O'Hara ◽  
Norman J Wilsman
Keyword(s):  
Young Male ◽  
Male Rats ◽  
Short Term ◽  
Catch Up ◽  
Bone Elongation

Short-Term effects of high dose estrogen on tibiae of growing male rats

1997 ◽  
Vol 60 (1) ◽  
pp. 37-42 ◽  
Author(s):  
G. K. Wakley ◽  
G. L. Evans ◽  
R. T. Turner
Keyword(s):  
Male Rats ◽  
High Dose ◽  
Short Term ◽  
Short Term Effects

Does food restriction retard aging by reducing the metabolic rate?

1985 ◽  
Vol 248 (4) ◽  
pp. E488-E490 ◽  
Author(s):  
R. McCarter ◽  
E. J. Masoro ◽  
B. P. Yu
Keyword(s):  
Metabolic Rate ◽  
Lean Body Mass ◽  
Body Mass ◽  
Food Restriction ◽  
Aging Process ◽  
Male Rats ◽  
Short Term ◽  
Ad Libitum ◽  
Group 2 ◽  
Group 1

Metabolic rate was determined by measuring O2 consumption in two groups of 6-mo-old male rats fed ad libitum (group 1) or maintained on a life-prolonging food-restriction regimen for 4.5 mo (group 2). These measurements were made continuously for 23.75 h under conditions nearly identical to those of the daily life of the rats. The metabolic rate per kilogram lean body mass was the same for both groups, a finding contrary to the hypothesis that food restriction retards the aging process and prolongs life by slowing the metabolic rate per unit of metabolic mass. This and our previous work strongly suggest that the classic views of the action of food restriction on aging must be re-evaluated because retardation of the aging process can occur without the restriction of calories or any other nutrient per unit of lean body mass. The long held belief that reducing food intake lowers the metabolic rate per unit of metabolic mass may be true in short-term dietary programs but appears not to be true when a significant portion of the life span is involved.

scholarly journals Characterization of New Selective Somatostatin Receptor Subtype-2 (sst2) Antagonists, BIM-23627 and BIM-23454. Effects of BIM-23627 on GH Release in Anesthetized Male Rats after Short-Term High-Dose Dexamethasone Treatment

Endocrinology ◽  
2002 ◽  
Vol 143 (4) ◽  
pp. 1218-1224 ◽  
Author(s):  
G. Tulipano ◽  
D. Soldi ◽  
M. Bagnasco ◽  
M. D. Culler ◽  
J. E. Taylor ◽  
...  
Keyword(s):  
Somatostatin Receptor ◽  
Glucagon Secretion ◽  
Male Rats ◽  
Receptor Subtype ◽  
High Dose ◽  
Dependent Manner ◽  
Short Term ◽  
Adult Rats ◽  
High Dose Dexamethasone

Abstract We here report a pharmacological characterization of two new somatostatin (SS) receptor subtype-2 (sst2) selective antagonists by evaluating their GH-releasing activity when administered, by different routes, in anesthetized adult rats and in freely moving 10-d-old rats. Moreover, we describe the effect of these SS antagonists on the GH response to GHRH after short-term high-dose dexamethasone (DEX) treatment in young male rats. BIM-23454 and BIM-23627, given iv, were able to counteract the SS-induced inhibition of GH secretion occurring after urethane anesthesia in a dose-dependent manner. In DEX-treated animals, the GH response to GHRH was partially blunted (5-min peak values, 270 ± 50 ng/ml in saline-treated vs. 160 ± 10 ng/ml in DEX-treated, P < 0.05); however, the simultaneous administration of BIM-23627 (0.2 mg/kg, iv) restored higher amplitude GH pulse, leading to a significantly higher overall mean GH response (area under the curve, 4200 ± 120 ng/ml/30 min vs. 2800 ± 100 ng/ml/30 min after GHRH alone; P < 0.05). The SS antagonists showed a reduced GH-releasing effect when administered sc or ip, likely attributable to decreased bioavailability, as compared with the iv route. SS antagonist administration also increased plasma glucagon, insulin, and glucose levels. Based on prior reports that sst2 tonically suppresses glucagon secretion, the antagonist most likely increased glucagon secretion from the pancreatic α-cells, with resultant increases in plasma glucose and then insulin.

scholarly journals A Conflicted Tale of Two Novel AR Antagonists In Vitro and In Vivo: Pyrifluquinazon Versus Bisphenol C

2019 ◽  
Vol 168 (2) ◽  
pp. 632-643 ◽  
Author(s):  
Leon Earl Gray ◽  
Johnathan R Furr ◽  
Justin M Conley ◽  
Christy S Lambright ◽  
Nicola Evans ◽  
...  
Keyword(s):  
Reproductive Tract ◽  
Ex Vivo ◽  
In Utero ◽  
Male Rats ◽  
High Dose ◽  
Short Term ◽  
Anogenital Distance ◽  
Hershberger Assay

Abstract Chemicals that disrupt androgen receptor (AR) function in utero induce a cascade of adverse effects in male rats including reduced anogenital distance, retained nipples, and reproductive tract malformations. The objective of this study was to compare the in vitro and in utero activities of two novel AR antagonists, bisphenol C (BPC) and pyrifluquinazon (PFQ). In vitro, BPC was as potent an AR antagonist as hydroxyflutamide. Furthermore, BPC inhibited fetal testis testosterone production and testis gene expression ex vivo. However, when BPC was administered at 100 and 200 mg/kg/d in utero, the reproductive tract of the male offspring was minimally affected. None of the males displayed reproductive malformations. For comparison, in utero administration of flutamide has been shown to induce malformations in 100% of males at 6 mg/kg/d. In vitro, PFQ was several orders of magnitude less potent than BPC, vinclozolin, or procymidone. However, in utero administration of 12.5, 25, 50, and 100 mg PFQ/kg/d on GD 14–18 induced antiandrogenic effects at all dosage levels and 91% of the males displayed reproductive malformation in the high dose group. Overall, BPC was ∼380-fold more potent than PFQ in vitro, whereas PFQ was far more potent than BPC in utero. Incorporating toxicokinetic and toxicodynamic data into in vitro to in vivo extrapolations would reduce the discordance between the in vitro and in utero effects of PFQ and BPC and combining in vitro results with a short-term Hershberger assay would reduce the uncertainty in predicting the in utero effects of antiandrogenic chemicals.

Ghrelin does not act as a short-term cognitive enhancer in young male humans

2015 ◽  
Vol 48 (06) ◽  
Author(s):  
N Kunath ◽  
N Müller ◽  
M Tonon ◽  
A Kopczak ◽  
A Steiger ◽  
...  
Keyword(s):  
Young Male ◽  
Cognitive Enhancer ◽  
Short Term
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