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PubMed1989

Photoperiod and parturition period in isolated or paired rats: influence of sight deprivation and social conditions.

Time of delivery was studied in normal (N) or enucleated (E) rats. Isolated (1/cage) at mating (day 1 of gestation), they were all anaesthetized on day 8 and some of them were then blinded. After anaesthesia, they were kept either alone (N and E) or in homogeneous (NN and EE) and heterogeneous (NE) pairs either under a 12L-12D or a 2L-22D light-dark (LD) cycle. Activity, monitored throughout the rest of pregnancy in 2 homogeneous (NN and EE) and heterogeneous (NE) pairs of rats, kept a marked circadian rhythm under each light regimen. Birth distributions differed according to LD cycle in normal (N or NN) but not in enucleated (E and EE) rats. Under the 12L-12D regimen, parturitions of N and E rats were divided into 2 parts, the majority occurred on the afternoon of day 22 before 21:00 h, the remainder were observed after 6:00 h on day 23. Under the 2L-22D regimen, N rats gave birth over one period, mainly on day 23, whereas E rats had the same birth distribution as those subjected to the 12L-12D LD cycle. In heterogeneous pairs of rats (NE), birth times were affected by photoperiod; under the 2L-22D regimen it was intermediate between those of homogeneous pairs (NN and EE). These results indicate that the eyes were the first link of the nervous chain by which photoperiod influenced birth time. Social conditions may also modulate the photodependent mechanism in ways which remain to be determined.

Animals↗
PubMed1992

Plasma osteocalcin concentrations in cows around parturition. The influence of a regular versus a very short dry period.

Plasma Ca, P, Mg and OC concentrations were compared between 2 groups of Holstein cows around 2nd calving. Thirteen cows were milked until their daily milk production was lower than 2 kg, which occurred 4 d before parturition. The control group (8 cows) was normally dried 8 weeks before the expected time of calving. Apart from the week following the initiation of the dry period where plasma OC concentrations were significantly lower in dried cows than in the control group (which would indicate lower bone remodeling in dried cows), no significant difference concerning Ca, P, Mg and OC concentrations were observed between the 2 groups of cows. This indicates that the only lack of 1 8-week-long dry period probably has no major immediate effect upon Ca and bone metabolism in young dairy cows given a convenient Ca and P daily intake. Nevertheless, the lack of the dried period might protect the cow against parturient hypocalcemia: the decrease in plasma Ca and P concentrations observed 12 h after calving was less intense in non-dried cows than in controls.

Animals↗
PubMedDate not supplied

Triiodothyronine (T3), insulin and characteristics of 5'-monodeiodinase (5'-MD) in mare's milk from parturition to 21 days post-partum.

It is generally accepted that hormones and tissue growth factors are supplied from mother to neonate via mammary secretion. Among the protein hormones, insulin and prolactin are considered as the most important milk components for neonates. The significance of the thyroid hormones, namely triiodothyronine (T3) generated locally by 5'-monodeiodinase (5'-MD) in the mammary tissues, for the mammary gland itself and for suckling neonates is still under consideration. In the present study the activity of the 5'-MD and the concentrations of T3 and insulin in mare's colostrum and milk during the first 21 days of lactation were measured. Post partum, T3 increased to its highest concentration around day 4 (1.14+/-0.08 nmol/L), then progressively decreased until day 7, reaching a relatively stable concentration of 0.71+/-0.06 nmol/L (overall mean for days 7-21). The colostral insulin concentration, highest on the day of parturition (401.0 +/-24.9 microU/mL), decreased to a nadir value (25.0+/-3.4 microU/mL) on day 5, after which it tended to increase. The mare's milk showed the presence of PTU-sensitive (type I) and PTU-insensitive (type II) 5'-monodeiodinases (5'-MD). Contrary to the classical type II 5'-MD, the mare's milk isoenzyme was inhibited non-competitively by aurothioglucose. A significant relationship (r=0.962, P < 0.01 ) between T3 concentration and 5'-MD activity, from the I st to the 6th lactational day was found, which may indicate a dependence of T3 concentration on the milk 5'-MD activity. The presence of 5'-MD of type II suggests that intra-mammary T3 generation may play a paracrine role supporting lactogenesis. Estimating that 1.8 microg of colostral T3 (0.456 microg/L) is consumed daily by a suckling foal, the T3 hormone action within the intestinal tract cannot be ruled out. This is the first paper to provide evidence of T3 and insulin concentrations, and of T4-5'-monodeiodinases activity in colostrum and milk of the mare.

Animals↗
PubMed1981

[Pregnancy and parturition in idiopathic thrombocytopenic purpura (author's transl)].

The article reports on the case of a 39-year old primipara with severe idiopathic thrombocytopenic purpura (ITP). The patient, who did not respond to corticosteroids, gave birth to a healthy child after thrombocyte substitution, parturition being effected by means of Caesarean section. The article discusses pathogenesis, prognosis and the therapeutic aspects of corticosteroid treatment, platelet substitution, splenectomy and mode of delivery.

Adrenal Cortex Hormones↗
PubMed2000

Human neutrophil collagenase (matrix metalloproteinase 8) in parturition, premature rupture of the membranes, and intrauterine infection.

OBJECTIVES: The mechanisms by which microbial invasion of the amniotic cavity leads to membrane weakening and rupture are poorly understood. Recently, endogenous host enzymes have been implicated in this process. Matrix metalloproteinases are a family of potent enzymes that degrade components of the extracellular matrix. Collagen type I provides the main tensile strength of the fetal membranes. Matrix metalloproteinase 8 (MMP-8), or neutrophil collagenase, degrades interstitial collagens, acting preferentially on collagen type I. This study was undertaken (1) to determine whether MMP-8 is present in amniotic fluid and whether its concentrations are changed in preterm and term labor and membrane rupture with and without intra-amniotic infection and (2) to determine whether the amniotic fluid concentrations of MMP-8 in labor at term are different in the lower and upper uterine compartments. STUDY DESIGN: A cross-sectional study was conducted and transabdominal amniocentesis was performed in women in the following categories: (1) midtrimester (n = 25), (2) preterm labor in the presence and absence of microbial invasion of the amniotic cavity (n = 86), (3) preterm premature rupture of the membranes in the presence and absence of microbial invasion of the amniotic cavity (n = 51), (4) term patients in labor and not in labor (n = 51), and (5) term premature rupture of membranes (n = 20). Additional paired samples of amniotic fluid were retrieved by transabdominal amniocentesis (upper compartment) and transvaginal amniocentesis (lower or forebag compartment) from 14 term patients (28 samples) in spontaneous labor with intact membranes. Amniotic fluid MMP-8 concentrations were determined with a sensitive and specific immunoassay. RESULTS: MMP-8 was detected in 95.4% (249/261) of all samples. (1) Spontaneous human parturition was associated with a significant increase in amniotic fluid concentrations of MMP-8 in both term and preterm gestation. Term (no labor median, 3.3 ng/mL; range, <0.06-38.6 ng/mL; vs labor median, 16.6 ng/mL; range, 0. 33-1650 ng/mL; P <.05). Patients with preterm labor who delivered preterm (in the absence of microbial invasion of the amniotic cavity) had a significantly higher median amniotic fluid MMP-8 concentration than those with preterm labor who delivered at term (preterm labor, term delivery median, 3.1 ng/mL; range, <0.06-415.1 ng/mL; vs preterm labor, preterm delivery median, 32.5 ng/mL; range, <0.06-6006.6 ng/mL;P <.003). (2) Spontaneous rupture of membranes in preterm gestation but not in term gestation was associated with elevated amniotic fluid concentrations of MMP-8. Preterm gestation (preterm labor, intact membranes median, 3.1 ng/mL; range, <0.06-415. 1 ng/mL; vs preterm premature rupture of membranes median, 35.1 ng/mL; range, 0.71-1184.1 ng/mL; P <.05). Term gestation (intact membranes median, 3.3 ng/mL; range, 0.24-38.6 ng/mL; vs rupture of membranes median, 5.6 ng/mL; range, 0.22-19.8 ng/mL; P =.9). (3) Microbial invasion of the amniotic cavity was associated with a significant increase in amniotic fluid MMP-8 concentration in patients with preterm labor and intact membranes, as well as in patients with preterm premature rupture of membranes. Preterm labor (no microbial invasion of the amniotic cavity, preterm delivery median, 32.5 ng/mL; range, <0.06-6006.6 ng/mL; vs microbial invasion of the amniotic cavity median, 208.1 ng/mL; range, 4.2-14,600 ng/mL; P <.001). Preterm premature rupture of membranes (no microbial invasion of the amniotic cavity median, 35.1 ng/mL; range, 0.71-1184. 1 ng/mL; vs microbial invasion of the amniotic cavity median, 317.9 ng/mL; range, 2.16-14,500 ng/mL; P <.01). (4) The median amniotic fluid MMP-8 concentrations were significantly higher in fluid obtained from the forebag compartment than in that obtained from the upper compartment (median, 66.2 ng/mL; range, 7.4-170 ng/mL; vs median, 13.3 ng/mL; range, 2-170 ng/mL; respectively; P <.01). (ABSTRACT TRUNCATED)

Amniocentesis↗
PubMed2001

Changes in rates of salivary estriol increases before parturition at term.

OBJECTIVE: The aim of this study was to characterize the increases of salivary estriol concentrations before the onset of labor at term. STUDY DESIGN: Salivary estriol concentrations were measured in weekly patient-collected samples by means of a sensitive (mean +/- SD threshold, 0.025 +/- 0.001 ng/mL; coefficient of variation, 3.8%) direct enzyme immunoassay in a microtiter plate format. The salivary estriol concentrations in 16 healthy pregnant women were characterized from 30 weeks' gestation until the time of parturition and delivery. Samples were stored frozen at collection and analyzed in batches after delivery. RESULTS: The median salivary estriol concentration profile revealed a nonlinear rise beginning from 30 weeks' gestation (0.89 ng/mL) until term (2.70 ng/mL, an increase of 201%). At 35 weeks' gestation the salivary estriol concentration median value increased sharply (positive inflection point, 50%-93% increase) at a demarcation between a slower increase during early pregnancy and a more rapid increase during late pregnancy. This positive inflection point associated with a late pregnancy increase characterized subgroups of pregnancies according to the lengths of gestation as follows: early term (delivered at <38 weeks 1 day's gestation), middle term (delivered at 38 weeks 1 day-40 weeks' gestation), and late term (delivered at >40 weeks' gestation). Five weeks before delivery the mean (+/-SEM) rate of rise in salivary estriol concentration was 0.50 +/- 0.13 ng/mL per week to 0.84 +/- 0.26 ng/mL per week in the early term group. The increase in rate for the middle term group was 0.32 +/- 0.06 ng/mL per week to 0.37 +/- 0.26 ng/mL per week, whereas in the late term group the rate of salivary estriol concentration rise was 0.37 +/- 0.03 ng/mL per week to -0.03 +/- 0.25 ng/mL per week. CONCLUSION: These data demonstrate in normal pregnancies (1) that a direct, nonradiometric measure of salivary estriol concentration can be used to monitor the late pregnancy increase in estriol production, (2) that 35 weeks' gestation marks a positive inflection point of the onset of increased estriol production, and (3) that the late pregnancy rise in salivary estriol concentration shows distinct patterns that tend to be characteristic of the length of pregnancy. These data support the concept that the rate of increase of estriol production is related to the timing of the onset of labor.

Adult↗
PubMed1982

Effects of induction of parturition in ewes with dexamethasone or oestrogen on concentrations of immunoglobulins in colostrum, and absorption of immunoglobulins by lambs.

Immunoglobulins were measured in colostral whey from untreated ewes or ewes treated on days 142-145 of gestation with 15 mg oestradiol benzoate (ODB) or 10, 17.5 or 25 mg dexamethasone m-sulfobenzoate (DEX) to induce parturition. DEX at all levels reduced the concentrations of immunoglobulins in colostrum, but ODB had no effect. In a second experiment, similar treatments of ODB and DEX were applied on day 143 of gestation. Lambs were removed from their dams at birth and fed a standard volume of pooled colostrum taken from untreated ewes. They were injected with an antigen (Brucella abortus) at 12 h and 4 weeks of age. Concentrations of immunoglobulins in blood plasma at 24 h after birth of lambs from DEX-treated ewes were lower than for lambs from untreated ewes or from those treated with ODB. Response to the antigen, monitored to 12 weeks of age, was unaffected by either drug. The impairment of transfer of immunoglobulins from ewe to lamb offers a possible explanation for the higher mortality among older lambs found previously after treatment of ewes with DEX.

Animals↗
PubMed1984

Total and free plasma concentrations of progesterone, cortisol and oestradiol-17 beta during pregnancy, parturition and early lactation in sows.

The total (bound plus free) concentrations of progesterone, 20 alpha-dihydroprogesterone, oestradiol-17 beta and cortisol were determined in the plasma of sows at three stages during pregnancy and more intensively from 5 days pre-partum to 5 days post-partum. The free fractions of progesterone, oestradiol-17 beta and cortisol were measured in the same samples by a rate dialysis method. Up to day 110 of gestation, the amounts of free hormone in plasma did not fluctuate independently of their total concentrations. During farrowing, the total and free concentrations of progesterone and cortisol varied independently of each other, whereas total and free oestradiol-17 beta declined simultaneously. The initiation of parturition was associated with a decrease in circulating total progesterone, and was accentuated by a decrease in the free fraction (P less than 0.005) so that its active free concentration was only 20% of its day 1 pre-partum value. Total and free cortisol concentrations rose rapidly during labour so that at 12-18 h after birth of the first piglet 30% of that cortisol in maternal plasma was free hormone.

Animals↗
PubMed1990

Control of pregnancy, parturition and luteolysis in marsupials.

In most eutherian species the function of the corpus luteum (CL) is influenced by extrinsic factors and it is subordinate to the pituitary, placenta, or uterus. In contrast, in marsupials the CL is relatively autonomous. Although the pituitary is essential for the formation of the CL, thereafter the secretory activity of the CL is independent of luteotrophic support, and the uterus is not luteolytic. Furthermore, the life span of the CL is unaffected by pregnancy, except in the Macropodidae (kangaroos and wallabies), in which the secretory activity of the CL is shortened under the influence of the fetus. At parturition the macropodid fetus, possibly via a release of glucocorticoids, causes the release of prostaglandins, presumed to be of uterine origin. The effect of the prostaglandin is to induce the release of prolactin from the maternal pituitary. Prolactin, and not prostaglandin, induces luteolysis and advances the events of post-partum oestrus. In the non-pregnant cycle, the mechanism of luteolysis is different; it does not involve prolactin, and the luteolytic signal is of non-uterine, possibly intrinsic, origin.

Animals↗
PubMed1995

Prostaglandins and parturition.

It seems likely that prostaglandins play a significant part in the mechanisms of parturition both at term and preterm. Concentrations of prostaglandins are increased in the blood, urine and amniotic fluid during labour. There are differences in the concentrations of prostaglandins in amniotic fluid from the forebag and hindbag. Nevertheless, if liquor is sampled only from the hindbag a highly significant increase in prostaglandin concentrations occurs throughout labour. Furthermore, we now have evidence that prostaglandin concentrations in amniotic fluid increase before the onset of labour. Prostaglandins are synthesized by uterine tissues and increased rates of production occur during labour. The amnion, chorion and decidua all contain mRNA for the newly-discovered inducible form of prostaglandin H synthase (PGHS-2) as well as mRNA for the constitutive form (PGHS-1). Using the reverse transcription polymerase chain reaction (RT-PCR) both mRNAs can be detected during late pregnancy whether women are in labour or not. PGHS-2 protein is detected by Western blot analysis in cells derived from all three tissues. There is regulation of PGHS-2 protein amounts by cytokines, phorbol esters and growth factors. For example, in amnion cells interleukin-1 beta induces a rapid increase in PGHS-2 mRNA levels followed by a decrease to undetectable levels within 4 h of treatment; PGHS-2 protein amounts are also elevated by this treatment. Administration of prostaglandins will induce labour and delivery, whereas inhibition of prostaglandin biosynthesis will delay labour and delivery. Hence, increased prostaglandin production is likely to be a key determinant of the onset and progression of the parturient process.

Amniotic Fluid↗
PubMed2003

A decline in the levels of progesterone receptor coactivators in the pregnant uterus at term may antagonize progesterone receptor function and contribute to the initiation of parturition.

The molecular events that lead to the onset of labor in humans and in other mammalian species remain unclear. We propose that a decline in coactivators containing histone acetylase activity in myometrium may contribute to the onset of labor by impairing the function of the progesterone-progesterone receptor (PR) complex. As assessed by semiquantitative and real-time RT-PCR, immunohistochemistry, and immunoblotting, expression of the PR coactivators cAMP-response element-binding protein (CREB)-binding protein and steroid receptor coactivators 2 and 3 was decreased in fundal uterine tissue of women in labor. Using the mouse as an animal model, we also found decreased coactivator levels in uterine tissues at term. In both human and mouse, the levels of acetylated histone H3 were also decreased in uterine tissues at term. Administration of trichostatin A, a specific and potent histone deacetylase inhibitor, to pregnant mice late in gestation increased histone acetylation and delayed the initiation of parturition by 24-48 h, suggesting the functional importance of the decline in histone acetylation in the initiation of labor. These findings suggest that the decline in PR coactivator expression and in histone acetylation in the uterus near term may impair PR function by causing a functional progesterone withdrawal. The resulting decrease in expression of PR-responsive genes should increase sensitivity of the uterus to contractile stimuli.

Acetyltransferases↗
PubMed1996

Oxytocin is required for nursing but is not essential for parturition or reproductive behavior.

Oxytocin, a neurohypophyseal hormone, has been traditionally considered essential for mammalian reproduction. In addition to uterine contractions during labor and milk ejection during nursing, oxytocin has been implicated in anterior pituitary function, paracrine effects in the testis and ovary and the neural control of maternal and sexual behaviors. To determine the essential role(s) of oxytocin in mammalian reproductive function, mice deficient in oxytocin have been generated using embryonic stem cell technology. A deletion of exon 1 encoding the oxytocin peptide was generated in embryonic stem cells at a high frequency and was successfully transmitted in the germ line. Southern blot analysis of genomic DNA from homozygote offspring and in situ hybridization with an exonic probe 3' of the deletion failed to detect any oxytocin or neurophysin sequences, respectively, confirming that the mutation was a null mutation. Mice lacking oxytocin are both viable and fertile. Males do not have any reproductive behavioral or functional defects in the absence of oxytocin. Similarly, females lacking oxytocin have no obvious deficits in fertility or reproduction, including gestation and parturition. However, although oxytocin-deficient females demonstrate normal maternal behavior, all offspring die shortly after birth because of the dam's inability to nurse. Postpartum injections of oxytocin to the oxytocin deficient mothers restore milk ejection and rescue the offspring. Thus, despite the multiple reproductive activities that have been attributed to oxytocin, oxytocin plays an essential role only in milk ejection in the mouse.

Animals↗
PubMed2002

Advances in bovine theriogenology in New Zealand. 1. Pregnancy, parturition and the postpartum period.

Unique systems of breeding and calving management have been developed to allow New Zealand cattle herd owners to maintain seasonally concentrated calving patterns. Improved pastures are used as the sole ration for most beef and dairy cows with limited conservation and no grain feeding. Patterns of calving are described in relation to herd Planned Start of Calving (PSC) dates, calculated as 282 days after the first date of insemination in the preceding seasonal artificial breeding (AB) programme. Corticosteroids have been systematically used in over 80% of New Zealand dairy herds to induce premature parturition (calving induction) during the third trimester of pregnancy for about 25 years, to condense calving patterns into periods of 6-12 weeks. Widespread use of calving induction has minimised the adverse effects of declining reproductive performance in dairy herds on the sustainability of seasonally concentrated calving. The use of calving induction is now discouraged on animal welfare grounds and due to possible consequences for the marketing of New Zealand dairy products. Recent declines in the reproductive performance of dairy herds are linked to increased prevalence of extended periods of postpartum anovulatory anoestrus (AA), which has become the major form of infertility in dairy herds in New Zealand and can be related to reliance on grazed pasture as the sole diet for cows of increasing genetic merit. The prevalence of AA is influenced by by parity, breed, recent genetic origin within a breed, body condition score, herd and year. management strategies such as once-daily milking, preferential grazing or feeding of silage, have not proven as successful as hormonal treatments. Although seasonal concentrated calving has remained a standard feature of the industry's low-cost, pasture-based system of management, continuing research will be required to economically maintain this pattern.

Journal Article↗
PubMed2000

Headache following parturition.

The incidence of headache following childbirth in 226 Nigerian women is 24.3% (n=55) or one in four births. Headache was more prevalent among women aged between 21 and 30 years (n=44); those of social class 3-5 (n=50); and also increased incidence with increasing parity, although these relationships did not reach significance. There is a highly significant association between the incidence of postparturition headache and evidence of stress (P=0.004), but not with a history of migraine (p=0.102). A highly significant association also exists between the incidence of postparturition headache and anaemia (Hb value less than 10 g/dl (68%), (p=0.004). Headache started on the day of delivery in the majority of cases (36.4%; n=20) although the median number of days of onset after delivery was 2 days. Post-natal headache may be associated with some underlying sociomedical factors which may be influenced by the fall in pregnancy hormones following parturition.

Journal Article↗
PubMed2002

Impact of asymptomatic maternal malaria parasitaemia at parturition on perinatal outcome.

A cross-sectional study involving 564 parturients who delivered singleton babies and 214 matched non-pregnant controls was carried out to determine the prevalence and impact of asymptomatic maternal malaria parasitaemia at parturition on the perinatal outcome. One hundred and forty (24.8%) parturients and 50 (23.4%) non-pregnant women were found to have asymptomatic malaria parasitaemia, respectively, while the congenital malaria rate in the neonates of the parasitaemic parturients was 0.7%. The incidence of malaria parasitaemia was higher in the para 2 and over (29.33%) as compare to the para 1 (21.43%) and primigravid (18.42%). There was no significant difference between the mean birth weight of infants delivered by parasitaemic parturients (2.93+/-0.61 kg) and aparasitaemic parturients (3.07+/-0.32 kg) (P=0.501). There was also no significant difference when comparing the mean placental weight of the parasitaemic mothers (0.60+/-0.15 kg) with that of the aparasitaemic mothers (0.62+/-0.20 kg) (P=0.329). Only in the para 2 and over was the mean placental weight of the parasitaemic mothers significantly lower than that of the aparasitaemia mothers (0.46+/-0.16 kg; 0.66+/-0.23 kg P=0.035). The mean packed cell volume of the parasitaemics parturients (30.89+/-1.87) was significantly lower than the aparasitaemic parturients (31.98+/-2.25) (P<0.001). Significant difference was not achieved between the parasitaemics and aparasitaemics inrespect of apgar score at 1 minute, or at 5 minutes, premature births (16.43%; 15.33%; P>0.05), stillbirth rate (3.57%; 2.59, P>0.05), mean placental index (0.204, 0.202, P>0.50) and mode of delivery. The findings in this study show that even though malaria parasitaemia is prevalent in our locality, the effects on maternal and fetal wellbeing are comparable with the aparasitaemics.

Apgar Score↗
PubMed1992

Exposure to mercury via breast milk in suckling offspring of maternal guinea pigs exposed to mercury vapor after parturition.

Exposure to an exogenous chemical via milk causes superimposition on the body burden that might have already existed in the neonatal organism due to in utero exposure. Such exposure via breast milk is avoidable, although transplacental exposure cannot be avoided at present. In this paper, mercury exposure via breast milk was examined in an animal model. Maternal guinea pigs were shortly exposed to mercury vapor at the mean concentrations of 6-10 mg/m3 immediately after parturition. Newborn guinea pigs were then nursed by the natural mothers. Mercury concentrations in breast milk and tissue samples were determined on d 3, 5, and 10 postpartum. Mercury concentrations in breast milk were slightly lower than plasma mercury concentrations of the maternal guinea pigs over the observation period. However, the decrease in the mercury concentration in breast milk with time was slower than that in maternal plasma. Mercury concentrations in major organs of the neonates were highest in kidney, followed by liver and lung. In brain and whole blood, mercury concentrations were slightly elevated compared with the nonexposed control. Organ distribution of mercury in the suckling neonates indicated that they were exposed via breast milk to inorganic, not elemental, mercury.

Animals↗
PubMed1974

Changes in the ribosome content, principal microsomal protein composition, and secretory character of mammary epithelial rough endoplasmic reticulum during differentiation. Evidence that messenger RNAs specific for milk proteins are incorporated into rough endoplasmic reticulum formed de novo after parturition.

The equilibrium density distribution, protein composition, and secretory character of mouse mammary epithelial rough microsomes have been determined during differentiation. The density range exhibited by the rough microsomes broadens during mammary development; rough microsomes within the 1.25-1.29 g/ml density range appear soon after conception and then within the 1.30-1.34 range after the onset of lactation. The appearance of these denser microsomes represents the progressive increase of the average ribosome content of the rough endoplasmic reticulum (ER) during gestation and lactation. Fractionation of rough microsomal proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals that two proteins, having molecular weights of 57,000 and 76,000, occur to a significant extent only during lactation and are then most prominent in the very dense rough microsomes of the 1.30-1.34 range. Nascent polypeptide chains discharged (by incubation with puromycin) from 17-days lactation rough microsomes in either the 1.21-1.29 or 1.30-1.34 density range are distributed equally between the intra- and extravesicular compartments. Whereas 36% of the chains are discharged intravesicularly from 1-day lactation rough microsomes in the 1.30-1.34 range, only 25% are so discharged from those in the 1.21-1.29 range. The results indicate (a) that there is no correlation between the relative levels in lactation rough microsomes of the two microsomal proteins which become prominent during lactation and the extent of secretory activity and (b) that for a short period after parturition the rough ER elements bearing high surface densities of ribosomes have a greater proportion of ribosomes synthesizing milk proteins than the rough ER elements with moderate ribosome densities.

Animals↗
PubMed1975

Vitamin profile of 174 mothers and newborns at parturition.

Thiamin, biotin, B12, folate, pantothenate, riboflavin, nicotinate, B6, vitamins A, E, C, and beta-cartene was estimated in the blood of 174 mothers and in the cord blood of their neonates at parturition. A vitamin profile of normal preganancy was established for mother and neonate. This was based on values obtained from 95 percent confidence limits in 74 mothers not taking oral vitamins and 133 mothers ingesting various vitamin supllements. Circulating vitamin levels in 38 neonates born to mothers with no laboratory evidence of hypovitaminemia was persented. The higher incidence of hypobitaminemia in gravidas not taking vitamins was folate, thiamin, vitamins A, C, B12, BL and nicotinate in descending order. Ingestion of vitamins supplements reduced the incidence of hypovitaminemia. A similar relationship held for neonates from these mothers. However, despite vitamin ingestion thiamin, folate, vitamins C, A, B6, B12 and nicotinate hypovitaminemia was evident. There was an approximate 1:2-5 ratio between mother and neonate blood vitamins; vitamins A, B6, E, and beta-carotene were exceptions. Vitamin B6 ran parallel, while vitamins A, B6, E, and beta-carotene ratios reversed in favor of the mother at an approximate ratio of 2:1, 4:1 and 7:1, respectively. It is concluded that vitamin profile for mother and neonate, taking into account values established from a lorge gravid population, should now permit an evaluation of the effects of hypoviteminemia on the outcome of pregnancy and infant health.

Adult↗