Normative reproductive indices for male and female adult Sprague-Dawley rats

Sokol, Rebecca Z.; Okuda, Helen; Stanczyk, Frank Z.; Wolfe, Gary W.; Delaney, Julie C; Chapin, Robert E.

doi:10.1016/s0010-7824(99)00017-7

Cited by 22 publications

(24 citation statements)

References 18 publications

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“…E2 levels oscillated from 4 to 6 weeks of age between 0.7 and 0.9 ng/dL, and no significant differences were observed in the comparison of IUGR to control offspring at these ages. However, E2 levels were increased at 8 weeks of age, a value that correlates with puberty for this rat strain, 28 and were maintained at this level up to 16 weeks of age or the end of the study, with no significant differences observed in the comparison of female IUGR with control offspring (Figure 4a). At puberty, recognized by vaginal opening, daily vaginal smearing was performed to identify the stage of estrous cycle at the time of E2 measurement.…”

Section: Plasma E2 Levelsmentioning

confidence: 84%

“…28 Furthermore, ovariectomy led to the development of significant elevations in MAP in adult female IUGR offspring with no effect in adult female control offspring. Thus, the possibility that E2 plays a protective role in the normalization of arterial pressure was strongly suggested.…”

Section: Discussionmentioning

confidence: 99%

“…We previously reported an important role for testosterone and the renal renin-angiotensin system (RAS) in the maintenance of established hypertension in adult or postpubertal male IUGR offspring. 27 Based on the fact that stabilization of blood pressure in female IUGR offspring is coincident with postpuberty or the age at which female rats reach maximum levels of estrogen for this strain, 28 we hypothesize that estrogen may protect against increases in blood pressure in postpubertal female IUGR offspring. In addition, based on renal RAS involvement in adult male IUGR hypertension 27 and experimental studies whereby estrogen modulates the renal RAS, 29 -32 we hypothesize that modulation of the RAS by estrogen may contribute to blood pressure regulation in female IUGR offspring.…”

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confidence: 99%

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Estrogen Protects Against Increased Blood Pressure in Postpubertal Female Growth Restricted Offspring

et al. 2007

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Abstract-Placental insufficiency in the rat results in intrauterine growth restriction and development of hypertension in prepubertal male and female growth-restricted offspring. However, after puberty, only male growth-restricted offspring remain hypertensive, whereas female growth-restricted offspring stabilize their blood pressure to levels comparable to adult female controls. Because female rats reach their maximum levels of estrogen at puberty, we hypothesize that estrogen may be a factor involved in the stabilization of blood pressure in adult female growth-restricted offspring. At 10 weeks of age, female control and growth-restricted offspring underwent ovariectomy or sham surgery and insertion of a telemetry probe. Mean arterial pressure was similar at 16 weeks of age between control (123Ϯ4 mm Hg) and growth-restricted offspring (122Ϯ2 mm Hg); however, ovariectomy led to a significant increase in blood pressure in growth-restricted offspring (140Ϯ2 mm Hg; PϽ0.05 versus intact counterpart) with no significant effect in controls (124Ϯ1 mm Hg). Estrogen replacement by subcutaneous minipellet initiated at 14 weeks of age in a subset of ovariectomized control and growth-restricted offspring reversed the effect of ovariectomy on blood pressure in growth-restricted offspring at 16 weeks of age (111Ϯ3 mm Hg; PϽ0.05 versus ovariectomized counterpart); renin angiotensin system blockade also abolished ovariectomy-induced hypertension in female growth-restricted offspring (106Ϯ2 mm Hg; PϽ0.05 versus ovariectomized counterpart). Therefore, sex differences are observed in this model of fetal programmed hypertension, and results from this study suggest that estrogen contributes to normalization of blood pressure in adult female growth-restricted offspring. Key Words: fetal programming Ⅲ intrauterine growth restriction Ⅲ ovariectomy Ⅲ estrogen Ⅲ renin angiotensin system H ypertension shows a clear age-related sex dimorphism. Nearly 1 in 3 adult Americans have hypertension. A higher percentage of men than women have hypertension until age 45 years, the percentage is similar from ages 45 to 54 years, and it becomes higher for women after that. 1 Thus, the risk of hypertension increases in women after the onset of menopause and continues to rise with age. 1-4 As a result, after menopause, a greater percentage of women have hypertension than age-matched men. 1,5,6 Epidemiological evidence suggests a regulatory role for estrogens in maintaining vascular function and structure. 7-9 Loss of ovarian function results in estrogen deficiency and increased risk for development of cardiovascular diseases, such as hypertension in postmenopausal women and women with ovarian surgical ablation. [7][8][9][10] In animal models of hypertension in which female rats are normotensive relative to their hypertensive male counterparts, ovariectomy induces hypertension. 11-14 Therefore, it seems that, while the ovaries are functional, women have a lower risk of cardiovascular disease than men, an observation supported by experimental studies.Alte...

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Section: Plasma E2 Levelsmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Estrogen Protects Against Increased Blood Pressure in Postpubertal Female Growth Restricted Offspring

et al. 2007

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“…Our laboratory reports that placental insufficiency in the rat leads to female growth restricted offspring that normalize their blood pressure after puberty (18), or the age at which female rats reach their maximum levels of estrogen in the strain (69). Blood pressure is significantly increased following ovariectomy in adult female growth restricted offspring in this model with no effect on blood pressure in adult female control offspring (Figure 2) (33).…”

Section: Role Of Estrogenmentioning

confidence: 87%

Sex differences in the fetal programming of hypertension

2008

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“…Female rodents demonstrate cycle irregularities at around 9-12 months of age (Sokol et al 1999, Spencer et al 2008, eventually becoming acyclic and entering 'estropause' at 12-18 months of age (Van Kempen et al 2011). The key differences between menopause and estropause may be understood in terms of circulating oestrogen levels, which fall dramatically in human menopause, but are maintained at a higher ambient level in rodents (Maffucci & Gore 2006).…”

Section: Reproductive Aging In Developmental Programmingmentioning

confidence: 99%

Sex differences in developmental programming models

2013

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The theory of developmental programming suggests that diseases such as the metabolic syndrome may be 'programmed' by exposure to adverse stimuli during early development. The developmental programming literature encompasses the study of a wide range of suboptimal intrauterine environments in a variety of species and correlates these with diverse phenotypic outcomes in the offspring. At a molecular level, a large number of variables have been measured and suggested as the basis of the programmed phenotype. The range of both dependent and independent variables studied often makes the developmental programming literature complex to interpret and the drawing of definitive conclusions difficult. A common, though under-explored, theme of many developmental programming models is a sex difference in offspring outcomes. This holds true across a range of interventions, including dietary, hypoxic, and surgical models. The molecular and phenotypic outcomes of adverse in utero conditions are often more prominent in male than female offspring, although there is little consideration given to the basis for this observation in most studies. We review the evidence that maternal energy investment in male and female conceptuses may not be equal and may be environment dependent. It is suggested that male and female development could be viewed as separate processes from the time of conception, with differences in both timing and outcomes.Reproduction (2013) 145 R1-R13

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Normative reproductive indices for male and female adult Sprague-Dawley rats

Cited by 22 publications

References 18 publications

Estrogen Protects Against Increased Blood Pressure in Postpubertal Female Growth Restricted Offspring

Estrogen Protects Against Increased Blood Pressure in Postpubertal Female Growth Restricted Offspring

Sex differences in the fetal programming of hypertension

Sex differences in developmental programming models

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