Maternal undernutrition programs offspring adrenal expression of steroidogenic enzymes

MicroRNA and mRNA sequencing analyses reveal key hepatic metabolic and signaling pathways responsive to maternal undernutrition in full-term fetal pigs

Maternal undernutrition is highly prevalent in developing countries, leading to severe fetus/infant mortality, intrauterine growth restriction, stunting, and severe wasting. However, the potential impairments of maternal undernutrition to metabolic pathways in offspring are not defined completely. In this study, two groups of pregnant domestic pigs received nutritionally balanced gestation diets with or without 50% feed intake restriction from 0 to 35 gestation days and 70% from 35 to 114 gestation days. Full-term fetuses were collected via C-section on day 113/114 of gestation. MicroRNA and mRNA deep sequencing were analyzed using the Illumina GAIIx system on fetal liver samples. The mRNA-miRNA correlation and associated signaling pathways were analyzed via CLC Genomics Workbench and Ingenuity Pathway Analysis Software. A total of 1189 and 34 differentially expressed mRNA and miRNAs were identified between full-nutrition (F) and restricted-nutrition (R) groups. The correlation analyses showed that metabolic and signaling pathways such as oxidative phosphorylation, death receptor signaling, neuroinflammation signaling pathway, and estrogen receptor signaling pathways were significantly modified, and the gene modifications in these pathways were associated with the miRNA changes induced by the maternal undernutrition. For example, the upregulated (p < 0.05) oxidative phosphorylation pathway in R group was validated using RT-qPCR, and the correlational analysis indicated that miR-221, 103, 107, 184, and 4497 correlate with their target genes NDUFA1, NDUFA11, NDUFB10 and NDUFS7 in this pathway. These results provide the framework for further understanding maternal malnutrition's negative impacts on hepatic metabolic pathways via miRNA-mRNA interactions in full-term fetal pigs.

Perinatal Protein Restriction Impacts Nuclear O-GalNAc Glycosylation in Cells of Liver and Brain Structures of the Rat

BACKGROUND

Post-translational modifications are key factors in the modulation of nuclear protein functions controlling cell physiology and an individual's health.

OBJECTIVES

This study examined the influence of protein restriction during the perinatal period on the nuclear O-N-acetylgalactosamine (O-GalNAc) glycosylation of cells from the liver and parts of the brain in the rat.

METHODS

Pregnant Wistar rats were divided into 2 groups on day 14 of pregnancy and fed ad libitum 1 of 2 isocaloric diets containing 24% (well-fed) or 8% (protein-restricted diet) casein until the end of the experiment. Male pups were studied after weaning at 30 d of life. Animals and their organ/tissues (liver, cerebral cortex, cerebellum and hippocampus) were weighed. Cell nuclei were purified, and the presence in nucleus and cytoplasm of all factors required for the initiation of O-GalNAc glycan biosynthesis, i.e., the sugar donor (UDP-GalNAc), enzyme activity (ppGalNAc-transferase) and the glycosylation product (O-GalNAc glycans), were evaluated by western blotting, fluorescent microscopy, enzyme activity, enzyme-lectin sorbent assay and mass spectrometry.

RESULTS

The perinatal protein deficit reduced progeny weight, as well as the cerebral cortex and cerebellum weight. UDP-GalNAc levels in the cytoplasm and nuclei of the liver, the cerebral cortex, cerebellum, or hippocampus were not affected by the perinatal dietary protein deficits. However, this deficiency affected the ppGalNAc-transferase activity localized in the cerebral cortex and hippocampus cytoplasm as well as in the liver nucleus, thus reducing the "writing" ppGalNAc-transferase activity of O-GalNAc glycans. In addition, liver nucleoplasm from protein-restricted offspring revealed a significant reduction in the expression of O-GalNAc glycans on important nuclear proteins.

CONCLUSIONS

Our results report an association between the consumption of a protein-restricted diet by the dam and her progeny with the modulation in the offspring' liver nuclei O-GalNAc glycosylation, which may ultimately regulate nuclear protein functions.

Sex-dependent effects of prenatal food and protein restriction on offspring physiology in rats and mice: systematic review and meta-analyses

BACKGROUND

Males and females may experience different effects of early-life adversity on life-long health. One hypothesis is that male foetuses invest more in foetal growth and relatively less in placental growth, and that this makes them susceptible to poor nutrition in utero, particularly if nutrition is reduced part-way through gestation.

OBJECTIVES

Our objectives were to examine whether (1) food and/ or protein restriction in rats and mice has consistent sex-dependent effects, (2) sex-dependency differs between types of outcomes, and (3) males are more severely affected when restriction starts part-way through gestation.

DATA SOURCES

PubMed and Web of Science were searched to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Eligible studies described controlled experiments that restricted protein or food during gestation in rats or mice, examined physiological traits in offspring from manipulated pregnancies, and tested whether effects differed between males and females.

RESULTS

Our search identified 292 articles, of which the full texts of 72 were assessed, and 65 were included for further synthesis. A majority (50) used Wistar or Sprague-Dawley rats and so these were the primary focus. Among studies in which maternal diet was restricted for the duration of gestation, no type of trait was consistently more severely affected in one particular sex, although blood pressure was generally increased in both sexes. Meta-analysis found no difference between sexes in the effect of protein restriction throughout gestation on blood pressure. Among studies restricting food in the latter half of gestation only, there were again few consistent sex-dependent effects, although three studies found blood pressure was increased in males only. Meta-analysis found that food restriction in the second half of gestation increased adult blood pressure in both sexes, with a significantly greater effect in males. Birthweight was consistently reduced in both sexes, a result confirmed by meta-analysis.

CONCLUSIONS

We found little support for the hypotheses that males are more affected by food and protein restriction, or that effects are particularly severe if nutrition is reduced part-way through gestation. However, less than half of the studies tested for sex by maternal diet interactions to identify sex-dependent effects. As a result, many reported sex-specific effects may be false positives.

Extracellular vesicles derived from bone marrow mesenchymal stem cells repair functional and structural rat adrenal gland damage induced by fluoride

The adrenal glands have striking morpho-biochemical features that render them vulnerable to the effects of toxins.

AIMS

This study was conducted to explore the therapeutic utility of extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) against fluoride-induced adrenal toxicity.

MATERIALS AND METHODS

The work included isolation and further identification of BMSC-EVs by transmission electron microscopy and flow cytometric analysis. Adrenal toxicity in rats was induced by oral administration of 300 ppm of sodium fluoride (NaF) in drinking water for 60 days followed by a single dose injection of BMSC-EVs. The effects of BMSC-EVs against NaF was evaluated by adrenal oxidant/antioxidant biomarkers, hormonal assay of plasma adrenocorticotrophic hormone (ACTH) and corticosterone (CORT) and mRNA gene expression quantitation for adrenal cortical steroidogenic pathway-encoding genes. Histopathological examination of the adrenal tissue was performed.

KEY FINDINGS

BMSC-EVs were effectively isolated and characterized. NaF exposure decreased adrenal superoxide dismutase and catalase activities, increased adrenal malondialdehyde levels, elevated plasma ACTH, diminished CORT concentrations and downregulated the adrenal cortical steroidogenic pathway-encoding genes. In addition, NaF-induced marked adrenal histopathological lesions.

SIGNIFICANCE

BMSC-EVs treatment repaired damaged adrenal tissue and recovered its function greatly following NaF consumption. BMSC-EVs reversed the toxic effects of NaF and reprogramed injured adrenal cells by activating regenerative processes.

Developmental programming of the female reproductive system-a review

Exposures to adverse conditions in utero can lead to permanent changes in the structure and function of key physiological systems in the developing fetus, increasing the risk of disease and premature aging in later postnatal life. When considering the systems that could be affected by an adverse gestational environment, the reproductive system of developing female offspring may be particularly important, as changes have the potential to alter both reproductive capacity of the first generation, as well as health of the second generation through changes in the oocyte. The aim of this review is to examine the impact of different adverse intrauterine conditions on the reproductive system of the female offspring. It focuses on the effects of exposure to maternal undernutrition, overnutrition/obesity, hypoxia, smoking, steroid excess, endocrine-disrupting chemicals, and pollutants during gestation and draws on data from human and animal studies to illuminate underlying mechanisms. The available data indeed indicate that adverse gestational environments alter the reproductive physiology of female offspring with consequences for future reproductive capacity. These alterations are mediated via programmed changes in the hypothalamic-pituitary-gonadal axis and the structure and function of reproductive tissues, particularly the ovaries. Reproductive programming may be observed as a change in the timing of puberty onset and menopause/reproductive decline, altered menstrual/estrous cycles, polycystic ovaries, and elevated risk of reproductive tissue cancers. These reproductive outcomes can affect the fertility and fecundity of the female offspring; however, further work is needed to better define the possible impact of these programmed changes on subsequent generations.

A heretical view: rather than a solely placental protective function, placental 11β hydroxysteroid dehydrogenase 2 also provides substrate for fetal peripheral cortisol synthesis in obese pregnant ewes

Exposure to glucocorticoid levels higher than appropriate for current developmental stages induces offspring metabolic dysfunction. Overfed/obese (OB) ewes and their fetuses display elevated blood cortisol, while fetal Adrenocorticotropic hormone (ACTH) remains unchanged. We hypothesized that OB pregnancies would show increased placental 11β hydroxysteroid dehydrogenase 2 (11β-HSD2) that converts maternal cortisol to fetal cortisone as it crosses the placenta and increased 11β-HSD system components responsible for peripheral tissue cortisol production, providing a mechanism for ACTH-independent increase in circulating fetal cortisol. Control ewes ate 100% National Research Council recommendations (CON) and OB ewes ate 150% CON diet from 60 days before conception until necropsy at day 135 gestation. At necropsy, maternal jugular and umbilical venous blood, fetal liver, perirenal fat, and cotyledonary tissues were harvested. Maternal plasma cortisol and fetal cortisol and cortisone were measured. Fetal liver, perirenal fat, cotyledonary 11β-HSD1, hexose-6-phosphate dehydrogenase (H6PD), and 11β-HSD2 protein abundance were determined by Western blot. Maternal plasma cortisol, fetal plasma cortisol, and cortisone were higher in OB vs. CON (p < 0.01). 11β-HSD2 protein was greater (p < 0.05) in OB cotyledonary tissue than CON. 11β-HSD1 abundance increased (p < 0.05) in OB vs. CON fetal liver and perirenal fat. Fetal H6PD, an 11β-HSD1 cofactor, also increased (p < 0.05) in OB vs. CON perirenal fat and tended to be elevated in OB liver (p < 0.10). Our data provide evidence for increased 11β-HSD system components responsible for peripheral tissue cortisol production in fetal liver and adipose tissue, thereby providing a mechanism for an ACTH-independent increase in circulating fetal cortisol in OB fetuses.

Gestational chronodisruption leads to persistent changes in the rat fetal and adult adrenal clock and function

KEY POINTS

Light at night is essential to a 24/7 society, but it has negative consequences on health. Basically, light at night induces an alteration of our biological clocks, known as chronodisruption, with effects even when this occurs during pregnancy. Here we explored the developmental impact of gestational chronodisruption (chronic photoperiod shift, CPS) on adult and fetal adrenal biorhythms and function. We found that gestational chronodisruption altered fetal and adult adrenal function, at the molecular, morphological and physiological levels. The differences between control and CPS offspring suggest desynchronization of the adrenal circadian clock and steroidogenic pathway, leading to abnormal stress responses and metabolic adaptation, potentially increasing the risk of developing chronic diseases.

ABSTRACT

Light at night is essential to a 24/7 society, but it has negative consequences on health. Basically, light at night induces an alteration of our biological clocks, known as chronodisruption, with effects even when this occurs during pregnancy. Indeed, an abnormal photoperiod during gestation alters fetal development, inducing long-term effects on the offspring. Accordingly, we carried out a longitudinal study in rats, exploring the impact of gestational chronodisruption on the adrenal biorhythms and function of the offspring. Adult rats (90 days old) gestated under chronic photoperiod shift (CPS) decrease the time spent in the open arm zone of an elevated plus maze to 62% and increase the rearing time to 170%. CPS adults maintained individual daily changes in corticosterone, but their acrophases were distributed from 12.00 h to 06.00 h. CPS offspring maintained clock gene expression and oscillation, nevertheless no daily rhythm was observed in genes involved in the regulation and synthesis of steroids. Consistent with adult adrenal gland being programmed during fetal life, blunted daily rhythms of corticosterone, core clock gene machinery, and steroidogenic genes were observed in CPS fetal adrenal glands. Comparisons of the global transcriptome of CPS versus control fetal adrenal gland revealed that 1078 genes were differentially expressed (641 down-regulated and 437 up-regulated). In silico analysis revealed significant changes in Lipid Metabolism, Small Molecule Biochemistry, Cellular Development and the Inflammatory Response pathway (z score: 48-20). Altogether, the present results demonstrate that gestational chronodisruption changed fetal and adult adrenal function. This could translate to long-term abnormal stress responses and metabolic adaptation, increasing the risk of developing chronic diseases.

Role of miR-29 in mediating offspring lung phenotype in a rodent model of intrauterine growth restriction

Considerable epidemiological and experimental evidence supports the concept that the adult chronic lung disease (CLD), is due, at least in part, to aberrations in early lung development in response to an abnormal intrauterine environment; however, the underlying molecular mechanisms remain unknown. We used a well-established rat model of maternal undernutrition (MUN) during pregnancy that results in offspring intrauterine growth restriction (IUGR) and adult CLD to test the hypothesis that in response to MUN, excess maternal glucocorticoids (GCs) program offspring lung development to a CLD phenotype by altering microRNA (miR)-29 expression, which is a key miR in regulating extracellular matrix (ECM) deposition during development and injury-repair. At postnatal day 21 and 5 mo, compared with the control offspring lung, MUN offspring lung miR-29 expression was significantly decreased in conjunction with an elevated expression of multiple downstream target ECM proteins [collagen (COL)1A1, COL3A1, COL4A5, and elastin], at both mRNA and protein levels. Importantly, MUN-induced changes in miR-29 and target gene expressions were at least partially blocked in the lungs of offspring of MUN dams treated with metyrapone, a selective GC synthesis inhibitor. Furthermore, dexamethasone treatment of cultured fetal rat lung fibroblasts significantly induced miR-29 expression along with the suppression of target ECM proteins. These data, along with the previously known role of miR-29 in regulating ECM deposition in vascular tissue in the MUN offspring, suggest miR-29 to be a common mechanistic denominator for the vascular and pulmonary phenotypes in the IUGR offspring, providing a novel potential therapeutic target.

Neonatal overfeeding increases capacity for catecholamine biosynthesis from the adrenal gland acutely and long-term in the male rat

A poor nutritional environment during early development has long been known to increase disease susceptibility later in life. We have previously shown that rats that are overfed as neonates (i.e. suckled in small litters (4 pups) relative to control conditions (12 pups)) show dysregulated hypothalamic-pituitary-adrenal axis responses to immune stress in adulthood, particularly due to an altered capacity of the adrenal to respond to an immune challenge. Here we hypothesised that neonatal overfeeding similarly affects the sympathomedullary system, testing this by investigating the biochemical function of tyrosine hydroxylase (TH), the first rate-limiting enzyme in the catecholamine synthesis. We also examined changes in adrenal expression of the leptin receptor and in mitogen-activated protein kinase (MAPK) signalling. During the neonatal period, we saw age-dependent changes in TH activity and phosphorylation, with neonatal overfeeding stimulating increased adrenal TH specific activity at postnatal days 7 and 14, along with a compensatory reduction in total TH protein levels. This increased TH activity was maintained into adulthood where neonatally overfed rats exhibited increased adrenal responsiveness 30 min after an immune challenge with lipopolysaccharide, evident in a concomitant increase in TH protein levels and specific activity. Neonatal overfeeding significantly reduced the expression of the leptin receptor in neonatal adrenals at postnatal day 7 and in adult adrenals, but did not affect MAPK signalling. These data suggest neonatal overfeeding alters the capacity of the adrenal to synthesise catecholamines, both acutely and long term, and these effects may be independent of leptin signalling.

Epigenetic Pathways in Human Disease: The Impact of DNA Methylation on Stress-Related Pathogenesis and Current Challenges in Biomarker Development

HPA axis genes implicated in glucocorticoid regulation play an important role in regulating the physiological impact of social and environmental stress, and have become a focal point for investigating the role of glucocorticoid regulation in the etiology of disease. We conducted a systematic review to critically assess the full range of clinical associations that have been reported in relation to DNA methylation of CRH, CRH-R1/2, CRH-BP, AVP, POMC, ACTH, ACTH-R, NR3C1, FKBP5, and HSD11β1/2 genes in adults. A total of 32 studies were identified. There is prospective evidence for an association between HSD11β2 methylation and hypertension, and functional evidence of an association between NR3C1 methylation and both small cell lung cancer (SCLC) and breast cancer. Strong associations have been reported between FKBP5 and NR3C1 methylation and PTSD, and biologically-plausible associations have been reported between FKBP5 methylation and Alzheimer's Disease. Mixed associations between NR3C1 methylation and mental health outcomes have been reported according to different social and environmental exposures, and according to varying gene regions investigated. We conclude by highlighting key challenges and future research directions that will need to be addressed in order to develop both clinically meaningful prognostic biomarkers and an evidence base that can inform public policy practice.

The Programming Power of the Placenta

Size at birth is a critical determinant of life expectancy, and is dependent primarily on the placental supply of nutrients. However, the placenta is not just a passive organ for the materno-fetal transfer of nutrients and oxygen. Studies show that the placenta can adapt morphologically and functionally to optimize substrate supply, and thus fetal growth, under adverse intrauterine conditions. These adaptations help meet the fetal drive for growth, and their effectiveness will determine the amount and relative proportions of specific metabolic substrates supplied to the fetus at different stages of development. This flow of nutrients will ultimately program physiological systems at the gene, cell, tissue, organ, and system levels, and inadequacies can cause permanent structural and functional changes that lead to overt disease, particularly with increasing age. This review examines the environmental regulation of the placental phenotype with particular emphasis on the impact of maternal nutritional challenges and oxygen scarcity in mice, rats and guinea pigs. It also focuses on the effects of such conditions on fetal growth and the developmental programming of disease postnatally. A challenge for future research is to link placental structure and function with clinical phenotypes in the offspring.

Adrenal steroidogenesis following prenatal dexamethasone exposure in the spiny mouse

Antenatal stress disturbs the development of the fetal hypothalamic-pituitary-adrenal axis and adrenal steroidogenesis. We investigated the effect of brief maternal exposure to high glucocorticoids (dexamethasone (DEX)) at mid- and late-pregnancy on adrenal structure and production of steroids in spiny mouse. Pregnant spiny mice were treated for 60 h with 125 μg/kg DEX or saline s.c. by osmotic minipump at day 20 (0.5) or 30 (0.75) of gestation. Immunohistochemical expression of steroidogenic acute regulatory-protein (StAR), 3β-hydroxysteroid dehydrogenase (3βHSD), 17-hydroxylase,17-20lyase (P450C17), and cytochromeb5 (CYTB5) was determined in adrenals on postnatal (P) day 170±20. DHEA, testosterone, and cortisol were measured by RIA. Maternal DEX at 20 days significantly reduced the expression of STAR, P450C17 (CYP17A1), and CYTB5 in the adrenal zona reticularis (ZR) of adult offspring, with greater change in male vs female offspring (P<0.05). Plasma DHEA was decreased in male offspring from DEX-treated (6.84±1.24 ng/ml) vs saline-treated (13±0.06 ng/ml; P=0.01) dams, and the DHEA:cortisol ratio was lower in males (P<0.05). Testosterone levels increased in male offspring from DEX (266.03±50.75 pg/ml) vs saline (83.47±32.3 pg/ml, P<0.05)-treated dams. DEX treatment at 0.75 gestation had no significant effect on any parameters measured. This study shows that brief exposure to excess glucocorticoid has long-term impacts on the ZR and adrenal steroidogenesis, affecting the secretion of DHEA and testosterone in male offspring, an effect produced at 0.5 but not at 0.75 gestation. DHEA is important for brain development, and its suppression in adult life might contribute to the neurobehavioral pathologies that can arise after illness and stress during pregnancy.

Developmental ORIgins of Healthy and Unhealthy AgeiNg: the role of maternal obesity--introduction to DORIAN

Europe has the highest proportion of elderly people in the world. Cardiovascular disease, type 2 diabetes, sarcopenia and cognitive decline frequently coexist in the same aged individual, sharing common early risk factors and being mutually reinforcing. Among conditions which may contribute to establish early risk factors, this review focuses on maternal obesity, since the epidemic of obesity involves an ever growing number of women of reproductive age and children, calling for appropriate studies to understand the consequences of maternal obesity on the offspring's health and for developing effective measures and policies to improve people's health before their conception and birth. Though the current knowledge suggests that the long-term impact of maternal obesity on the offspring's health may be substantial, the outcomes of maternal obesity over the lifespan have not been quantified, and the molecular changes induced by maternal obesity remain poorly characterized. We hypothesize that maternal insulin resistance and reduced placental glucocorticoid catabolism, leading to oxidative stress, may damage the DNA, either in its structure (telomere shortening) or in its function (via epigenetic changes), resulting in altered gene expression/repair, disease during life, and pathological ageing. This review illustrates the background to the EU-FP7-HEALTH-DORIAN project.

Excess maternal glucocorticoids in response to in utero undernutrition inhibit offspring angiogenesis

To test the hypothesis that inhibition of offspring angiogenesis by maternal undernutrition (MUN) is mediated by maternal glucocorticoids, 3 groups of dams were studied: controls received ad libitum food; MUN dams were food restricted by 50% from day 10 of gestation; and metyrapone (MET) dams were food restricted and treated with 0.5 mg/mL of MET, a glucocorticoid synthesis inhibitor. The MUN reduced birth weights, reduced vascular endothelial growth factor (VEGF) abundance in P1 aortas, reduced VEGF and VEGF-R2 abundances in P1 mesenteric arterioles, reduced arteriolar endothelial nitric oxide synthase abundance, reduced microvessel density in the anterior tibialis, reduced endothelial cell branching in culture, reduced arteriolar immunoreactivity for proliferating cell nuclear antigen (PCNA), increased active caspase 3 in P1 mesenteric arterioles, and decreased matrix metalloproteinase (MMP)-2 and MMP-9 abundances in lysates of P1 aortas. All of these effects were prevented by treatment with metyrapone. Collectively, these findings suggest that reduced angiogenesis in MUN offspring involves direct inhibitory effects of maternal glucorticoid on fetal VEGF and its receptors.

11β-hydroxysteroid dehydrogenases: intracellular gate-keepers of tissue glucocorticoid action

Glucocorticoid action on target tissues is determined by the density of "nuclear" receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental "programming." The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues.

Maternal nutrient restriction in the ewe from early to midgestation programs reduced steroidogenic enzyme expression and tended to reduce progesterone content of corpora lutea, as well as circulating progesterone in nonpregnant aged female offspring

BACKGROUND

Previously we reported decreased circulating progesterone and fertility in one and two year old ewes born to undernourished mothers. This study was designed to investigate if this reduction in progesterone persisted into old age, and if it did, what mechanisms are involved.

METHODS

Ewes were fed a nutrient restricted (NR, 50% of NRC recommendations) or control (C, 100% of NRC) diets from day 28 to 78 of gestation, then all were fed to requirements through parturition and weaning. Female offspring (4 per treatment group) were maintained as a group and fed to requirements from weaning until assigned to this study at 6 years of age. Ewes were synchronized for estrus (day 0) and blood samples were collected daily from day 0 to day 11 before necropsy on day 12. Blood serum and luteal tissue were assayed for progesterone concentrations by validated radioimmunoassay.

RESULTS

Circulation progesterone concentrations tended to be lower (P = 0.06) in NR than C offspring from day 0 to 11 of the estrous cycle. While total luteal weight was similar across groups, total progesterone content also tended to be reduced (P = 0.07) in luteal tissue of NR than C offspring. Activity of hepatic progesterone catabolizing enzymes and selected angiogenic factors in luteal tissue were similar between groups. Messenger RNA expression of steroidogenic enzymes StAR and P450scc were reduced (P < 0.05), while protein expression of StAR tended to be reduced (P < 0.07) and P450scc was reduced (P < 0.05) in luteal tissue of NR versus C offspring.

CONCLUSIONS

There appears to be no difference in hepatic steroid catabolism that could have led to the decreased serum progesterone. However, these data are consistent with the programming of decreased steroidogenic enzyme expression in CL of NR offspring, leading to reduced synthesis and secretion of progesterone.