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Biomedical subjects

F A Simmen

Publications and source records attributed to F A Simmen.

At least 55 records · Page 3Linked to original sources
PubMed1993

Expression of components of the insulin-like growth factor system in pig mammary glands and serum during pregnancy and pseudopregnancy: effects of oestrogen.

To gain insight into the involvement and interactions of the insulin-like growth factors (IGFs) and estrogen in mammary growth and differentiation, the temporal expression of mammary mRNAs encoding components of the IGF system in pregnant and pseudopregnant pigs was examined. Pseudopregnant pigs received 5 mg oestradiol valerate or vehicle daily from day 45 after oestrus and underwent mammary biopsy on days 60, 90 or 112. In mammary tissue of pregnant pigs, steady-state levels of the mRNAs encoding IGF-I, IGF-II and type-I IGF receptor as well as the levels of the membrane-associated type-II IGF receptor were higher during the early phase of mammogenesis (< or = day 45) than during the subsequent stages of mammary development. Mammary IGF-I, IGF-II and type-I receptor mRNAs were expressed at their lowest levels around day 90 of pregnancy (20-40% of those for day 30 of pregnancy) coincident with the onset of beta-casein mRNA accumulation. Mammary IGF-binding protein-2 (IGFBP-2) mRNA levels increased twofold during the latter half of pregnancy, whereas the amount of IGFBP-3 mRNA declined after day 30 to undetectable levels by mid-pregnancy. Pseudopregnant pigs had reduced levels of these mRNAs (except for IGF-II) relative to their pregnant counterparts and this was associated with premature differentiation of mammary tissue as reflected by an earlier onset of beta-casein mRNA accumulation in the former. The administration of oestradiol valerate decreased the levels of IGF-I and type-I IGF receptor mRNAs by day 60 of pseudopregnancy, but the reverse was evident by day 112. Oestradiol administration increased beta-casein mRNA levels in pseudopregnant pigs, but had no effect on mammary IGFBP-2 and IGFBP-3 mRNA levels. Mammary IGF content was greater in late pregnancy (> or = day 90) and pseudopregnancy than at early pregnancy. Serum IGF-I and IGF-II levels declined steadily during pregnancy and this was similar to, but not correlated with, mammary IGF mRNA levels, whereas in pseudopregnant pigs, serum IGF concentrations did not change temporally or in response to oestradiol. Serum IGFBP-2 levels were unaltered during pregnancy or pseudopregnancy, but serum IGFBP-3 levels declined after day 60 of pregnancy. In pseudopregnant pigs, serum IGFBP-3 levels did not change temporally, but declined after oestradiol treatment. Results indicate that mammary IGF-I and type-I IGF receptor systems are down-regulated during pregnancy-associated differentiation of this tissue and in response to oestrogen.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Dietary clofibric acid increases intestinal fatty acid binding protein activity and apparent lipid digestibility in weanling swine.

The effects of supplementation of dietary clofibric acid (.5% wt/wt) on fatty acid binding protein (FABP) activity, apparent lipid digestibility, and serum cholesterol concentrations were evaluated in weanling pigs. Twenty-four barrows were allotted by weight and litter to a randomized complete block design with two treatments (basal vs clofibric acid) in six replicates. Nutrient digestibility measurements were made for a 2-wk period, after which the pigs were killed and tissues were collected. No differences in BW, liver, proximal small intestine, distal small intestine, and proximal and distal intestinal mucosa weights were observed. Apparent lipid digestibility was greater (P < .05) for the overall 2-wk period in clofibric acid-supplemented pigs (81.5 vs 76.6%). This paralleled the increased FABP activity in the distal small intestine (P < .001) of clofibric acid-supplemented pigs. Proximal intestine and liver FABP activities were unaffected by dietary treatment. Serum cholesterol concentrations were markedly lowered by clofibric acid supplementation. During wk 1, pigs fed the basal diet had twofold greater (P < .01) serum cholesterol concentrations, whereas during wk 2, basal-fed pigs had fourfold greater (P < .01) serum cholesterol concentrations (81.5 vs 18.3 mg/dL). These results suggest that elevated intestinal FABP activities may augment fatty acid absorption from the gastrointestinal tract.

Animal Feed↗
PubMed1992

Intestinal development and fatty acid binding protein activity of newborn pigs fed colostrum or milk.

Newborn pigs (n = 20) were gavage-fed sow's colostrum, defatted colostrum, milk, defatted milk or a 5% lactose solution over 24 h in order to evaluate effects on growth and functional differentiation of small intestine. Colostrum-fed pigs had greater (p less than 0.01) mucosal mass in the proximal half of the small intestine than did the milk- or lactose-fed groups. Total fatty acid binding protein (FABP) activity and FABP activity per mg DNA in proximal intestines of colostrum-fed pigs exceeded that for the lactose group. FABP activities (per g mucosa or mg soluble protein) were greater (p less than 0.01) in the proximal segments of small intestines of pigs fed whole versus the corresponding defatted secretion. These results indicate that the feeding of colostrum specifically augments perinatal intestinal growth and differentiation as manifested by increased cellular hypertrophy and FABP activity. Milk lipid and unidentified factor(s) enriched in colostrum are inducers of intestinal FABP activity.

Animals↗
PubMed1992

Differential expression, during the estrous cycle and pre- and postimplantation conceptus development, of messenger ribonucleic acids encoding components of the pig uterine insulin-like growth factor system.

The temporal patterns of endometrial expression for mRNAs encoding insulin-like growth factor-I (IGF-I), IGF-II, IGF-binding protein-2 (IGFBP-2), and the type I IGF receptor (IGF-IR) were elucidated in cyclic and pregnant pigs. Peak levels of IGF-I mRNAs occurred on day 12 in cyclic and early pregnant gilts, while IGFBP-2 mRNA levels were lowest on day 10. Pregnant gilt endometrium had higher levels of both RNA classes than the corresponding cyclic endometrium. IGF-II and IGF-IR mRNAs remained low during this period. In pregnant pig endometrium and rat uterus, levels of IGF-I mRNA decreased, while those of IGF-II and IGFBP-2 mRNAs increased with stage of pregnancy. Decreased endometrial production of IGF-I mRNA during pregnancy paralleled that in the myometrium. IGF-II mRNA tissue abundance was placenta greater than endometrium greater than myometrium. In contrast, IGFBP-2 mRNA levels were higher in endometrium than in placenta and myometrium. Endometrial expression of IGF-II mRNAs was limited to surface and glandular epithelial cells; epithelial and stromal cells expressed IGFBP-2 mRNAs at comparable levels. Expression of IGF-IR mRNAs was low and did not change with pregnancy. The endometria of two breeds of pigs that exhibit different levels of prolificacy were also examined for IGF mRNAs. On day 12, endometrium from the Large White breed with high conceptus mortality had higher levels of IGF-II and IGFBP-2 mRNAs than did endometrium from the Meishan breed with low conceptus mortality. Expression of IGF-I mRNAs was higher in endometria of Meishan than Large White gilts on day 12. The differential expression of IGF mRNAs with stage of gestation and the correlation of relative ratios of IGF mRNAs with prolificacy during the critical period of maternal recognition of pregnancy suggest an important role(s) for IGFs in conceptus and fetal development.

Animals↗
PubMed1991

Peptide growth factors and proto-oncogenes in mammalian conceptus development.

Development of mammalian conceptuses (embryo and associated membranes) in utero is an extremely complex, programmed orchestration of cellular activities that include proliferation, differentiation, migration, and death. Failure of conceptuses to develop is a significant, though not well-understood, problem in human and animal reproduction. Increased understanding of molecular and cellular processes in these events is ultimately required to determine the mechanisms responsible for developmental failures. Peptide growth factors, their associated proteins (carrier proteins and membrane receptors), and proto-oncogenes (the normal, cellular counterparts of retroviral oncogenic proteins) are intimately involved in normal and abnormal cellular growth regulation. This paper highlights recent work which suggests the involvement of these proteins in critical aspects of conceptus growth and uterine-conceptus interactions during the peri-implantation period.

Animals↗
PubMed1991

Regulation of synthesis of uterine secretory proteins: evidence for differential induction of porcine uteroferrin and antileukoproteinase gene expression.

Mechanisms regulating the expression of two pregnancy-associated proteins of the porcine uterus, namely the iron-transport protein uteroferrin (UF) and the lysosomal serine proteinase-inhibitor antileukoproteinase (ALP), were investigated by comparing the effects of estrogen (E), progesterone (P4), and conceptuses on the steady-state levels of their mRNAs. For UF, the expression of mRNA with production and secretion of the corresponding protein was also investigated. Progesterone increased the levels of endometrial UF mRNA and of secreted UF, but did not affect the levels of ALP mRNA in ovariectomized gilts that had received P4 treatment for 8 days. Estrogen inhibited the accumulation of endometrial UF mRNA, increased UF secretion in these gilts, but had no effect on levels of ALP mRNA. Administration of E to gilts on Day 11 of the cycle slightly diminished UF mRNA levels at 1 h post-E; had no effect at 6, 12, and 24 h post-E; and increased levels of secreted UF in uterine luminal fluids 24 h post-E. The presence of conceptuses increased levels of endometrial ALP mRNA and decreased UF protein in uterine luminal fluids, but did not affect levels of endometrial UF mRNA. Myometrium, endometrium, and placenta from Day 75 and Day 105 pregnant gilts were also evaluated for ALP and UF mRNA expression to determine regional expression of these steroid-regulated genes. Myometrium and endometrium expressed comparable levels of UF and ALP mRNAs within Days 75 or 105, but placenta did not express detectable levels of mRNA for either protein. Within the myometrium, UF protein is immunolocalized mostly to the inner circular and to a lesser extent to the outer longitudinal layer of smooth muscle. These results indicate that E, P4, and presence of conceptuses differentially affect endometrial expression of ALP and UF mRNAs and secretion of UF.

Acid Phosphatase↗
PubMed1991

Insulin-like growth factors in sheep uterine fluids: concentrations and relationship to ovine trophoblast protein-1 production during early pregnancy.

Uterine luminal fluids (ULFs) from Days 10, 12, 14, and 16 cyclic (C) and pregnant (Px) ewes were analyzed for presence of insulin-like growth factors (IGF-I, IGF-II) and other mitogenic factor(s). IGF content and non-IGF mitogenic activity were measured by IGF RIAs after removal of IGF binding proteins and by stimulatory effects on DNA synthesis of density arrested AKR-2B cells, respectively. ULF IGF-I content was not different between days, but differences in IGF-I between C and Px groups at Day 16 (C greater than Px) were found (p less than 0.05). ULF IGF-II content was not different between C and Px ewes; however, differences among days (p less than 0.01) were apparent. In both C and Px ewes, Day 14 ULF had highest IGF-II content (C: 4.60 +/- 0.98 ng/ml, Px: 5.39 +/- 1.38 ng/ml). In Day 12 and Day 14 (C and Px) ULF, IGF-II concentration was about 10-fold greater than that of IGF-I. AKR-2B mitogenic activity in ULF differed among days (p less than 0.01), but not between C and Px ewes. Highest activity was observed for Day 14 and Px ULF, whereas lowest activity was for Day 10 C and Day 16 Px ULF. Sephadex G-200 gel-filtration chromatography of ULF from Day 14 Px ewes demonstrated mitogenic activity in the column void volume fractions and in the 30-kDa size range of eluted proteins. Day 13 conceptuses were cultured in serum-free medium to define the effect of exogenous IGFs on ovine trophoblast protein-1 (oTP-1) secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Constitutive expression of uterine receptors for insulin-like growth factor-I during the peri-implantation period in the pig.

Insulin-like growth factor-I (IGF-I), synthesized by the uterine endometrium of cyclic and early pregnant gilts, accumulates in the uterine luminal fluid, where it comes in contact with the developing conceptus and the rapidly growing uterus. The uterus and the conceptus thus represent potential target sites for the biological effects of IGF-I, provided high-affinity Type I receptors are present. This study was undertaken to evaluate the expression of functional IGF-I receptors in the endometrium and myometrium of pregnant (Day 10, 12, and 15) gilts and in the endometrium of cyclic (Day 15) and pseudopregnant (Day 15) gilts and to correlate levels of these receptors with temporally regulated uterine production of IGF-I. Specific binding of 125I-IGF-I to endometrial membranes pretreated with MgCl2 (4 M) at 4 degrees C for 16 h, was saturable and membrane concentration-dependent. Competition of 125I-IGF-I binding to endometrial membranes was highest with unlabeled IGF-I greater than IGF-II much greater than insulin, whereas porcine relaxin was noncompetitive. Affinity cross-linking of endometrial membranes with 125I-IGF-I followed by SDS-PAGE and autoradiography revealed two labeled bands of Mr greater than 200,000 and Mr 135,000, with the major band being the Mr 135,000 species. Scatchard analysis of 125I-IGF-I binding to endometrial membranes from Day 12 pregnant gilts revealed a single class of binding sites with a dissociation constant (Kd) = 4.08 +/- 0.09 nM. Membranes prepared from endometrium of Day 10, 12, and 15 pregnant gilts exhibited comparable 125I-IGF-I binding (p greater than 0.05) that was higher (p less than 0.001) than that for the corresponding myometrial membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Affinity Labels↗
PubMed1991

Expression of messenger RNAs encoding insulin-like growth factor-I, -II, and insulin-like growth factor binding protein-2 in bovine endometrium during the estrous cycle and early pregnancy.

The present study characterized the changes in concentrations of insulin-like growth factors-I and -II (IGF-I and IGF-II) in uterine luminal flushings, and the endometrial mRNA levels of IGF-I, IGF-II, and IGF binding protein-2 (IGFBP-2) obtained from Days 0 through 18 of the bovine estrous cycle and early pregnancy. Concentrations of IGF-I and IGF-II in uterine flushings were greater on Days 0 and 5 than on other days of the estrous cycle or pregnancy. Northern blot analysis of endometrial poly(A)+ RNA revealed two major transcripts of 7.5 and 1.0 Kb for IGF-I, one major transcript of 4.0 Kb for IGF-II, and one major transcript of 1.3 Kb for IGFBP-2. RNA dot-blot analyses indicated that endometrial expression of IGF-I mRNA was unaffected by day of the estrous cycle or status (cyclic vs. pregnancy). However, endometrial expression of IGF-II mRNA was greater in pregnant than in cyclic endometrium on Days 15 and 18. Levels of endometrial IGFBP-2 mRNA increased (p less than 0.05) between Days 10 and 18 of the estrous cycle and early pregnancy. Results suggest that the presence of the bovine conceptus has a stimulatory effect on endometrial expression levels of IGF-II, whereas progesterone appears to be involved with enhancement of IGFBP-2.

Animals↗
PubMed1991

Comparative aspects of conceptus signals for maternal recognition of pregnancy.

Maintenance of corpus luteum (CL) function is essential for establishment of pregnancy in mammals. Estrogens from pig conceptuses (embryo and associated membranes) initiate events that, with prolactin, redirect secretion of the uterine luteolytic hormone prostaglandin F2 alpha (PGF) from an endocrine (to uterine veins) to an exocrine (to uterine lumen) direction to prevent luteolysis. Ovine conceptuses secrete ovine trophoblast protein-1 (oTP-1), which exhibits high amino acid sequence relatedness with alpha II interferons (IFN alpha II) and inhibits synthesis of endometrial receptors for oxytocin and uterine production of luteolytic pulses of PGF. Estrogens and oTP-1 are local antiluteolytic signals to endometrium, whereas human chorionic gonadotrophin (hCG) appears to have a direct luteotrophic effect on CL. A progestational endometrium secretes proteins that serve as growth factors, transport proteins, regulatory proteins and enzymes, as well as transporting nutrients into the uterine lumen to support conceptus development.

Animals↗
PubMed1991

Ontogeny of insulin-like growth factors (IGF-I and IGF-II) and IGF-binding proteins in porcine serum during fetal and postnatal development.

The insulin-like growth factors (IGF-I and IGF-II) circulate in plasma in association with IGF-binding proteins (IGFBPs). As a first step to understanding the regulation of expression of these proteins in pigs, we characterized the ontogeny of circulating IGFs and IGFBPs during fetal and early postnatal development. Serum IGFs were separated from IGFBPs, before IGF RIA, by acidification and chromatography on C18 Sep-Pak cartridges. The IGF-I levels increased during the latter half of fetal life from 11 +/- 1 ng/ml on day 60 to 37 +/- 3 ng/ml on day 112 (2-3 days before term) and further increased postnatally to 227 +/- 21 to 265 +/- 26 ng/ml) and also increased higher than IGF-I levels, with no obvious developmental pattern, during fetal life (170 +/- 21 to 265 +/- 26 ng/ml) and also increased postnatally by 2-fold (463 +/- 29 ng/ml on day 42). These results support the view that IGF-II is a fetal and postnatal growth factor, whereas IGF-I is primarily a postnatal growth mediator in pigs. Serum IGF-binding proteins were identified by Western ligand blotting. Five IGFBPs with apparent mol wt of 43K, 39K, 34K, 31K, and 26K were detected in fetal and postnatal sera. The two largest proteins were shown to be glycoproteins and immunologically related to porcine (p) IGFBP-3, suggesting that they are glycosylation variants of pIGFBP-3. The abundance of these two IGFBPs increased coincidently with increasing serum IGF-I levels. The 34K IGFBP was immunologically related to rIGFBP-2 and was 2- to 3-fold more abundant in fetal serum than in postnatal serum. The 31K IGFBP was resolved into a triplet and also was a component of pIGFBP-3 immunoprecipitates. Similarly, the 26K IGFBP was present in pIGFBP-3 immunoprecipitates. The 31K and 26K IGFBPs represented a minor portion of serum IGF-binding activity in fetal and postnatal pigs and exhibited no obvious developmental patterns. It is hypothesized that the postnatal increases in serum IGF-I and 43K and 39K IGFBPs as well as the decrease in the 34K IGFBP are driven by GH action.

Animals↗
PubMed1991

Effects of insulin-like growth factor-I on aromatase cytochrome P450 activity and oestradiol biosynthesis in preimplantation porcine conceptuses in vitro.

The effects of insulin-like growth factor-I (IGF-I) on aromatase P450 activity and steroid production in preimplantation pig conceptuses were evaluated in vitro. Conceptuses recovered from gilts on days 10 and 12 of pregnancy were incubated for 6 h in modified Eagle's Minimum Essential Medium (MEM) plus IGF-I (0.1 microgram/ml) or insulin (8.5 micrograms/ml), and conceptuses were monitored for their ability to convert [1,2-3H]beta-testosterone into oestrogens. Aromatase activity of day-10 conceptuses was low and unaffected by IGF-I or insulin. In contrast, basal aromatase activity in day-12 conceptuses was about threefold higher and was further increased by IGF-I (P less than 0.02), but was unaffected by insulin. To determine whether higher aromatase P450 activity was associated with increased oestradiol production, concentrations of oestradiol were determined by radioimmunoassay in culture medium of day-11 and -12 conceptuses, after incubation in MEM alone or in the presence of dehydroepiandrosterone (DHA, 1 microgram/ml) with or without IGF-I (0.1 microgram/ml) or insulin (0.1 or 8.5 micrograms/ml) for 24 h. Conceptuses in MEM plus DHA produced more oestradiol (P less than 0.01) than those in MEM alone. Addition of IGF-I or insulin did not increase the effect of DHA. Basal oestradiol production was dependent on conceptuses size; however, IGF-I or insulin did not affect basal or DHA-stimulated oestradiol production regardless of conceptus size. These findings demonstrate that IGF-I can modulate aromatase activity in vitro, without affecting overall de-novo steroidogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Somatic cell mapping and restriction fragment length polymorphism analysis of bovine insulin-like growth factor I.

The DNA isolated from cow-hamster hybrid somatic cells segregating bovine chromosomes was analyzed by Southern blotting and hybridization with a heterologous [32P]-labeled porcine cDNA probe encoding insulin-like growth factor I (IGF-I). Thirteen of 25 cow-hamster hybrid cell lines exhibited the bovine-specific IGF-I fragment. Analysis for the retention or loss of bovine IGF-I with markers previously screened against the same panel of hybrid cells revealed a 100% concordance with lactate dehydrogenase B of bovine syntenic group U3 located on bovine chromosome 5. Restriction fragment length analyses of genomic DNA from animals representing five breeds (Angus, Polled Hereford, Simmental, Gelbvieh, and Belgian Blue) and from seven half-sib Angus calves indicated that polymorphisms for the genomic composition of the bovine IGF-I gene may exist in cattle populations.

Animals↗
PubMed1990

Amblyomma americanum: identification of tick salivary gland antigens from unfed and early feeding females with comparisons to Ixodes dammini and Dermacentor variabilis.

Salivary gland antigens involved in host resistance to tick feeding by Amblyomma americanum (lone star tick) have been identified. Gland extracts from unfed and partially fed 12-, 48-, 72-, 96-, and 120-hr females and their corresponding midgut tissues were analyzed by immunoblotting with sera from naturally immune and hyperimmune sheep and rabbits. Polypeptides at 90, 75, 58, 45, 33, and 23 kDa from the salivary glands of A. americanum females were consistently observed with antibodies from both sheep and rabbits. No antigens unique to tick midgut tissue were detected with immune sera. Female Dermacentor variabilis and Ixodes dammini shared 90- and 45-kDa salivary gland antigens with A. americanum, and these may represent conserved polypeptides. We speculate that some of the salivary gland antigens represent components of tick cement, while others are playing some other yet undetermined role in tick feeding.

Animals↗
PubMed1990

Fibroblast mitogens in swine milk include an epidermal growth factor-related peptide.

Mammary secretions obtained from lactating sows can support in vitro growth of mammalian cells when added to Dulbecco's Modified Eagle Medium. In order to identify the growth factors present within, sow milk was fractionated and fractions having mitogenic activity were identified by their ability to stimulate DNA synthesis in density-arrested, quiescent (murine) AKR-2B fibroblasts. A prominent mitogenic activity (peak III) was observed in the 3,000-5,000 Mr range. This activity was partially purified by (1) preparative Sephadex G-200 chromatography, (2) gel-filtration in Sephadex G-50 columns and (3) DEAE-cellulose anion exchange chromatography. The last step resolved peak III activity into at least two distinct components. One component was highly-purified by use of reverse-phase high-performance liquid chromatography (RP-HPLC). This activity was identified as an epidermal growth factor (EGF)-related peptide based on its inactivation by polyclonal antibody (IgG fraction) specific for murine EGF (mEGF) and proteolytic agents. The other component is unrelated to EGF. Using cloned mEGF cDNA as a probe, the presence of EGF-related mRNA in lactating mammary tissues and newborn pig small intestine was also demonstrated. These factors may contribute to the preferential growth of gastrointestinal tissues in neonatal pigs.

Animals↗
PubMed1990

Lactational variation and relationship to postnatal growth of insulin-like growth factor-I in mammary secretions from genetically diverse sows.

Mammary secretions obtained from four groups of sows at parturition and on days 7, 14 and 21 of lactation were defatted and assayed for total protein and insulin-like growth factor-I (IGF-I). Sows (n = 57) represented two breeds (Landrace and Duroc) and two genetic lines (selected for differences in sow productivity index, SPI) within each breed. Colostrum of Duroc sows was 4-6 fold and 30-60 fold greater in protein (P less than .001) and IGF-I (P less than .001) concentrations, respectively, than the corresponding day 7 milk from these sows. In contrast, the colostrum of Landrace sows was 2-3 fold and 30-50 fold greater in protein (P less than .001) and IGF-I (P less than .001) concentrations, respectively, than the corresponding day 7 milk. The IGF-I content in milk from Duroc sows did not differ among days 7, 14 and 21 of lactation, whereas the IGF-I content of day 7 milk from Landrace sows exceeded those for the corresponding 14 day and 21 day secretion (P less than .05). IGF-I concentration in days 14 and 21 milk was higher in Duroc (P less than .001 respectively) than Landrace sows. No significant differences in total protein or IGF-I content of mammary secretions were observed between the selected and control lines within each breed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Isolation, characterization, and developmental expression of pig intestinal fatty acid-binding proteins.

The goal of this study was to characterize and quantify intestinal fatty acid-binding proteins of the pig. Small intestinal mucosa from 13-19 kg pigs was homogenized and centrifuged to obtain cytosol. Isolation of fatty acid-binding proteins from delipidated cytosol was achieved using molecular sieve, oleic acid affinity, and ion exchange chromatography. Fatty acid-binding protein isolation was monitored using a fatty-acid binding assay in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Antisera to rat liver-fatty acid-binding protein cross reacted with an isolated intestinal fatty acid-binding protein of Mr = 13,000, whereas antisera to rat intestine-fatty acid-binding protein was not cross reactive with isolated pig intestinal proteins. These experiments identify a pig intestinal fatty acid-binding protein that exhibits strong immunochemical similarity to rat liver-fatty acid-binding protein. Cytosol prepared from intestinal mucosa of pigs at -4, 2, 4, 7, 15, 22, 28, and 35 d of age was assayed for fatty acid-binding protein activity. Preweaning fatty acid-binding protein activity in cytosol was maximal at 7 days of age when expressed as total jejunal fatty acid binding per kilogram bodyweight, intestinal or mucosal weight or milligram total protein. After weaning (21 d), fatty acid-binding protein activities declined to 28 days, but increased again by 35 days. Total soluble fatty acid-binding protein activity in pig intestine is regulated during postnatal development and this may account in part for the altered intestinal absorption of lipids observed in young pigs at weaning.

Journal Article↗