Effects of space flight on ovarian-hypophyseal function in postpartum rats

Burden, Hubert W.; Zary, J.; Lawrence, Irvin E.; Jonnalagadda, P.; Davis, Melissa; Hodson, Charles A.

doi:10.1530/jrf.0.1090193

Cited by 24 publications

(10 citation statements)

References 19 publications

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“…Burden et al [42] reported no change in estrogen or progesterone levels in pregnant females flown in the microgravity environment of space. Megory and Oyama [26] reported reduced prolactin levels in periparturient dams exposed to gravitational loads spanning 1.76 ϫ g to 4.17 ϫ g relative to 1.0 ϫ g controls.…”

Section: Discussionmentioning

confidence: 98%

Maternal Reproductive Experience Enhances Early Postnatal Outcome Following Gestation and Birth of Rats in Hypergravity1

Ronca

Baer

Daunton

et al. 2001

Biology of Reproduction

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A major goal of space life sciences research is to broaden scientific knowledge of the influence of gravity on living systems. Recent spaceflight and centrifugation studies demonstrate that reproduction and ontogenesis in mammals are amenable to study under gravitational conditions that deviate considerably from those typically experienced on Earth (1 x g). In the present study, we tested the hypothesis that maternal reproductive experience determines neonatal outcome following gestation and birth under increased (hyper) gravity. Primigravid and bigravid female rats and their offspring were exposed to 1.5 x g centrifugation from Gestational Day 11 either through birth or through the first postnatal week. On the day of birth, litter sizes were identical across gravity and parity conditions, although significantly fewer live neonates were observed among hypergravity-reared litters born to primigravid dams than among those born to bigravid dams (82% and 94%, respectively; 1.0 x g controls, 99%). Within the hypergravity groups, neonatal mortality was comparable across parity conditions from Postnatal Day 1 through Day 7, at which time litter sizes stabilized. Maternal reproductive experience ameliorated neonatal losses during the first 24 h after birth but not on subsequent days, and neonatal mortality was associated with changes in maternal care patterns. These results indicate that repeated maternal reproductive experience affords protection against neonatal losses during exposure to increased gravity. Differential mortality of neonates born to primigravid versus bigravid dams denotes gravitational load as one environmental mechanism enabling the expression of parity-related variations in birth outcome.

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Section: Discussionmentioning

confidence: 98%

Maternal Reproductive Experience Enhances Early Postnatal Outcome Following Gestation and Birth of Rats in Hypergravity1

Ronca

Baer

Daunton

et al. 2001

Biology of Reproduction

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“…The pituitary‐gonadal axis has previously been reported to be influenced by alterations in gravity (1–4). Veeramachaneni et al .…”

Section: Discussionmentioning

confidence: 99%

“…Testosterone (T) secretion in mammals is normally mediated by the gonadotropin, luteinizing hormone (LH). Exposure to altered gravity (i.e., microgravity and centrifugation) has been shown to affect the pituitary‐gonadal axis in mammals (1–4). During spaceflight, astronauts exhibited a significant increase in plasma LH; however, plasma T was reduced (4, 5).…”

mentioning

confidence: 99%

Urinary Excretion of LH and Testosterone from Male Rats During Exposure to Increased Gravity: Post‐Spaceflight and Centrifugation

Ortiz

Wade

Morey-Holton

2000

Proc Soc Exp Biol Med

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Abstract. A dissociation between plasma luteinizing hormone (LH) and testosterone (T) appears to exist during exposure to altered gravity. The pulsatile nature of LH release and the diurnal variability of T secretion may mask or bias the effects of altered gravity on the pituitary‐gonadal axis when analyzing plasma concentrations. Therefore, we examined the relationship between the excretion of urinary LH and T in male Sprague‐Dawley rats during exposure to increased gravity upon return to Earth following a 14‐day spaceflight (n = 6) and by 12 days of centrifugation at 2g (n = 8). Excreted LH and T were elevated on the first 3 days postflight. Excreted T was elevated between Days 1 and 8 of centrifugation; however, excreted LH was reduced on Days 2 and 3 compared with control animals. Excreted LH and T were significantly correlated (R = 0.731 and 0.706, respectively) in postspaceflight and centrifuged animals. Correlation curves had similar slopes (0.0213 and 0.023, respectively), but different y‐intercepts (–1.43 and 3.32, respectively). The sustained increase in excreted T during centrifugation suggests that the pituitary‐gonadal axis in postspaceflight animals may adapt quicker to increased gravity. The upward shift in the correlation curve exhibited by the centrifuged animals suggests that the sensitivity of LH‐induced T release is increased in these animals. The previous dissociation between plasma LH and T during altered gravity was not observed in the present study in which excreted LH and T were measured.

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“…To date, studies of ovarian function and fertility in mice exposed to microgravity during NASA Space Shuttle flights were of short duration (<12 days) and, importantly, all included the effects of live reentry prior to collection of tissues and analysis of animal behavior 3 , 7 . Similarly, pregnant female rats flown on Cosmos 1514 (1982), NASA-NIH Rodent (R)1 (STS-66 in 1994), and NASA-NIH R2 (STS-70 in 1995) were of short duration (4.5–11 days) and had live animal return 8 – 10 . Notably, in the pregnant rats no effects of spaceflight on healthy and atretic ovarian antral follicle populations, fetal wastage in utero, plasma concentrations of progesterone and luteinizing hormone (LH) or pituitary content of follicle stimulating hormone (FSH) were noted 8 .…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, pregnant female rats flown on Cosmos 1514 (1982), NASA-NIH Rodent (R)1 (STS-66 in 1994), and NASA-NIH R2 (STS-70 in 1995) were of short duration (4.5–11 days) and had live animal return 8 – 10 . Notably, in the pregnant rats no effects of spaceflight on healthy and atretic ovarian antral follicle populations, fetal wastage in utero, plasma concentrations of progesterone and luteinizing hormone (LH) or pituitary content of follicle stimulating hormone (FSH) were noted 8 . Spaceflight, however, significantly increased plasma concentrations of FSH and decreased pituitary content of LH analyzed postpartum (day 22–23; 8 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of spaceflight aboard the International Space Station on mouse estrous cycle and ovarian gene expression

et al. 2021

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Ovarian steroids dramatically impact normal homeostatic and metabolic processes of most tissues within the body, including muscle, bone, neural, immune, cardiovascular, and reproductive systems. Determining the effects of spaceflight on the ovary and estrous cycle is, therefore, critical to our understanding of all spaceflight experiments using female mice. Adult female mice (n = 10) were exposed to and sacrificed on-orbit after 37 days of spaceflight in microgravity. Contemporary control (preflight baseline, vivarium, and habitat; n = 10/group) groups were maintained at the Kennedy Space Center, prior to sacrifice and similar tissue collection at the NASA Ames Research Center. Ovarian tissues were collected and processed for RNA and steroid analyses at initial carcass thaw. Vaginal wall tissue collected from twice frozen/thawed carcasses was fixed for estrous cycle stage determinations. The proportion of animals in each phase of the estrous cycle (i.e., proestrus, estrus, metestrus, and diestrus) did not appreciably differ between baseline, vivarium, and flight mice, while habitat control mice exhibited greater numbers in diestrus. Ovarian tissue steroid concentrations indicated no differences in estradiol across groups, while progesterone levels were lower (p < 0.05) in habitat and flight compared to baseline females. Genes involved in ovarian steroidogenic function were not differentially expressed across groups. As ovarian estrogen can dramatically impact multiple non-reproductive tissues, these data support vaginal wall estrous cycle classification of all female mice flown in space. Additionally, since females exposed to long-term spaceflight were observed at different estrous cycle stages, this indicates females are likely undergoing ovarian cyclicity and may yet be fertile.

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Effects of space flight on ovarian-hypophyseal function in postpartum rats

Cited by 24 publications

References 19 publications

Maternal Reproductive Experience Enhances Early Postnatal Outcome Following Gestation and Birth of Rats in Hypergravity1

Maternal Reproductive Experience Enhances Early Postnatal Outcome Following Gestation and Birth of Rats in Hypergravity1

Urinary Excretion of LH and Testosterone from Male Rats During Exposure to Increased Gravity: Post‐Spaceflight and Centrifugation

Effects of spaceflight aboard the International Space Station on mouse estrous cycle and ovarian gene expression

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