Reproduction and Breeding

Baker, Dennis E.J.

doi:10.1016/b978-0-12-074901-0.50014-9

Cited by 28 publications

(20 citation statements)

References 29 publications

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“…At this age, sexual maturation has already been achieved (10). Animals were grown in our animal house and kept at 22-25 C temperature, and 50 -55% humidity.…”

Section: Materials and Methods Animalsmentioning

confidence: 99%

Influence of Sex Differences on the Renal Secretion of Organic Anions

et al. 1998

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The kidney's responsiveness to male sexual hormones has been often neglected. Renal secretion of organic anions is higher in male than in female individuals; as a consequence, most of the xenobiotics that are excreted from the organism through this pathway are eliminated more rapidly by males than by female animals. To gain further insight into this issue, we studied in vitro and in vivo characteristics of the transport of p-aminohippurate (PAH), a suitable marker for this system, in male and female rats, under different hormonal conditions. Kinetics of PAH showed a shorter elimination half-time in male than in female rats (t(1/2el): male = 16.2 +/- 2.1 min, female = 25.7 +/- 4.5 min, P < 0.05). Castration of male rats increased t(1/2el) to a value similar to that of female rats (t(1/2el): orchiectomized rat = 28.1 +/- 7.1 min). Testosterone treatment of female rats increased the elimination rate to a value similar to that of male rats. In vitro PAH uptake by renal cortical slices from intact male rats was higher than that by slices from orchiectomized rats. Kinetic analyses of PAH uptake suggest that the difference was caused by a lower number of transporting molecules in orchiectomized than in intact animals, whereas the transporting capacity for each carrier was similar in male and in orchiectomized rats. Our results suggest that testosterone increases the number of functional carriers for PAH in the kidney.

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“…At this age, sexual maturation has already been achieved (10). Animals were grown in our animal house and kept at 22-25 C temperature, and 50 -55% humidity.…”

Section: Materials and Methods Animalsmentioning

confidence: 99%

Influence of Sex Differences on the Renal Secretion of Organic Anions

et al. 1998

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“…To reduce any influence that the female sex hormones may have on the volume of infarction, all females (unless otherwise stated) were in metestrus at the time of MCAO. The stage of the estrous cycle was determined by smear test, 8 which was carried out by an animal technician with extensive experience in this procedure. Metestrus is the stage in the 4-day cycle when estrogens and progesterone are at their lowest levels in the circulation.…”

Section: Methodsmentioning

confidence: 99%

Genetic and Gender Influences on Sensitivity to Focal Cerebral Ischemia in the Stroke-Prone Spontaneously Hypertensive Rat

et al. 1999

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Abstract-We have investigated genetic transmission of increased sensitivity to focal cerebral ischemia and the influence of gender in the stroke-prone spontaneously hypertensive rat (SHRSP). Halothane-anesthetized, 3-to 5-month-old male and female Wistar-Kyoto rats (WKY), SHRSP, and the first filial generation rats (F 1 crosses 1 and 2) underwent distal (2 mm) permanent middle cerebral artery occlusion (MCAO) by electrocoagulation. Key Words: rats, stroke-prone spontaneously hypertensive Ⅲ cerebral ischemia, focal Ⅲ gender Ⅲ estrus Ⅲ estrogen Ⅲ middle cerebral artery occlusion T he stroke-prone spontaneously hypertensive rat (SHRSP) was established from Wistar-Kyoto rats (WKY) and is an inbred animal model of cerebrovascular disease. 1 Spontaneous strokes occur in the SHRSP, and the role of a genetic factor in stroke is highlighted by the resistance of the related SHR to spontaneous strokes despite hypertension and similar diets.SHRSP exhibit an increased sensitivity to ischemia and an increased volume of infarction after experimentally induced focal cerebral ischemia compared with their reference strain, the WKY. This has been shown by ligation 2 or electrocoagulation 3,4 of the middle cerebral artery (MCA). One reason for the increased sensitivity of the SHRSP to stroke may be reduced blood flow through collateral vessels between the MCA and anterior and posterior cerebral arteries. The collaterals have been postulated to have an impaired ability to dilate and a smaller internal diameter compared with those in normotensive Wistar rats. 5 In addition, more marked ischemic glutamate increases in SHRSP than WKY may be related to stroke sensitivity. 6 Recently, we revealed a genetic component to the increased sensitivity after experimental ischemia in the SHRSP. We linked increased volume of infarction 24 hours after MCA occlusion (MCAO) to a locus on rat chromosome 5 with a logarithm of odds (LOD) of 16.6. 4 Having previously demonstrated a dominant mode of inheritance for this phenotype in F 1 cross 2 hybrid rats (WKY father), 7 we now use a different set of reciprocal crosses especially bred for these experiments to examine genetic transmission and any influence of the origin of the Y chromosome (SHRSP male progenitor versus WKY male progenitor) on infarct volume. We also investigate the effects of sex differences and control for estrous status during ischemia induction-the first F 1 analysis to do so. MethodsAll experiments were carried out under license from the Home Office and were subject to the Animals (Scientific Procedures) Act, 1986. Breeding and housing of SHRSP and WKY have been previously described. 4 Two parental crosses were performed espe-

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“…Female rats were housed overnight with adult males (four females:one male), according to harem methodology (Baker 1991), and the first day of pregnancy was determined based on the detection of sperm in the vaginal smear. All rats were housed in collective cages under standard conditions (22 AE 2 8C, 12 light:12 h darkness cycle, with free access to water and food).…”

Section: Animals and Dietsmentioning

confidence: 99%

Proteasome activity is altered in skeletal muscle tissue of tumour-bearing rats a leucine-rich diet

Ventrucci¹,

Mello²,

Marcondes³

2004

Endocr Relat Cancer

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Leucine can modulate skeletal muscle metabolism by enhancing protein synthesis and decreasing proteolysis. In this study, we investigated the effects of leucine on the ubiquitin-proteasome system in skeletal muscle of pregnant tumour-bearing rats fed a leucine-rich diet. Pregnant Wistar rats were distributed into three groups that were fed a semi-purified control diet (C, control; W, Walker tumour-bearing; P, pair-fed) and three other groups of pregnant rats fed a semi-purified leucine-rich diet (L, leucine; WL, Walker tumour-bearing; PL, pair-fed). The tumour-bearing rats were injected subcutaneously with a suspension of Walker 256 tumour cells. Protein synthesis and degradation were measured in gastrocnemius muscle; the total protein content and tissue chymotrypsin-like and alkaline phosphatase enzyme activities were also determined. Muscle protein extracts were run on SDS-PAGE to assess the expression of the myosin heavy chain (MHC), 20S a proteasome subunit, 19S MSSI ATPase regulator subunit and 11S a subunit. Although tumour growth decreased the incorporation of [ 3 H]-Phe, the concomitant feeding of a leucine-rich diet increased the rate of protein synthesis. Muscle proteolysis in both tumour-bearing groups was increased more than in the respective control groups. Conversely, the leucine-rich diet caused less protein breakdown in the WL group than in the W group. Only the W group showed a significant reduction (71%) in the myosin content. In WL rats, the 20S proteasome content (32 kDa band) was reduced, while the expression of the 19S subunit was 3-fold less than in the W group and the 11S proteasome subunit reduced, to around 32% less than in the W group. These findings clearly indicate that leucine can stimulate protein synthesis and inhibit protein breakdown in pregnant rats, probably by modulating the activation of the ubiquitin-proteasome system during tumour growth.

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Reproduction and Breeding

Cited by 28 publications

References 29 publications

Influence of Sex Differences on the Renal Secretion of Organic Anions

Influence of Sex Differences on the Renal Secretion of Organic Anions

Genetic and Gender Influences on Sensitivity to Focal Cerebral Ischemia in the Stroke-Prone Spontaneously Hypertensive Rat

Proteasome activity is altered in skeletal muscle tissue of tumour-bearing rats a leucine-rich diet

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