Biomedical subjects

R L Matteri

Publications and source records attributed to R L Matteri.

At least 37 records · Page 2Linked to original sources

PubMed1999

Non-surgical catheterization of the jugular vein in young pigs.

Current methods utilized for serial blood collection in the young pig are limited due to the stress and/or discomfort to which the pig is exposed. Thus, we have developed a non-surgical, minimally invasive cannulation technique which allows jugular vein catheter placement in the young pig without causing extended discomfort or stress. The procedure described is rapid (approximately 8 min/pig) and relatively simple, requiring only minimal anaesthesia for immobilization of the pig during the procedure. Routinely, 2-week-old piglets are standing in their pens within 15-20 min from initiation of the procedure. Piglets recover rapidly from the procedure and display no clinical indications of pain or discomfort. Serum concentrations of cortisol, a standard indicator of stress and/or discomfort, are asymptomatic within 2 h of completing the procedure (k = 26.14+/-3.03 ng/ml). Stress is limited to the initial immobilization of the piglets. With this technique of cannulation, we routinely maintain catheter patency for 2 days, and often for as long as 5 days.

Anesthetics, Inhalation↗

PubMed1999

Birth by caesarian section alters postnatal function of the hypothalamic-pituitary-adrenal axis in young pigs.

Eight crossbred sows were selected for the present study (n = 4 vaginal delivery and n = 4 Caesarian section [C-section]). Gestation length did not differ between vaginal delivery and C-section pigs (113.6 +/- .1 and 113.2 +/- .3 d, respectively; P > .16). Blood and tissue samples from 38 pigs were collected at birth. All remaining pigs were sustained with vaginal-delivery sows until 2 wk of age (n = 39). At 2 wk of age, remaining pigs were catheterized for blood sample collection to assess pituitary-adrenal responsiveness to an injection of corticotropin-releasing hormone (CRH; 10 microg/kg). Blood samples were collected at -30, -15, 0, 5, 10, 20, 40, 60, and 90 min; pigs received CRH or saline at time 0. Pigs were killed and tissue samples were collected immediately following the last blood sample. Serum concentrations of ACTH and cortisol (CS) were measured. Total RNA was isolated from the pituitary and adrenal glands to evaluate gene expression for mRNA specific for pro-opiomelanocortin (POMC) and for the ACTH receptor. Centrifuged clot:blood ratio was reduced in the C-section pigs at birth (P < .001) and at 2 wk of age (P < .043), compared with the vaginally delivered pigs. Basal serum concentration of ACTH was greater in C-section than in vaginally delivered pigs at birth (P = .01) but did not differ at 2 wk of age (P = .42). Basal serum concentration of CS was not different at birth (P = .86) but was greater in C-section pigs than in vaginally delivered pigs at 2 wk of age (P < .04). Serum concentration of ACTH was not different (P > .99) between the two groups of pigs following the CRH challenge. However, serum concentration of CS was greater (P < .05) in C-section pigs following the CRH challenge. Expression of ACTH receptor mRNA tended to be greater in C-section pigs at birth (P < .063) and at 2 wk of age (P < .016). There was no difference in POMC mRNA between treatments (P > .73); however, there was a developmental increase (P < .001) from birth to 2 wk of age. These data indicate that the birth process plays an important role in postnatal function of the hypothalamic-pituitary-adrenal axis in young pigs.

Adrenocorticotropic Hormone↗

PubMed1998

Endocrine responses to weaning and changes in post-weaning diet in the young pig.

The effects of weaning and changing post-weaning diet composition on growth patterns and growth-related hormonal profiles were evaluated in neonatal pigs. Forty-eight crossbred piglets were assigned to two groups (n = 24/group) based on weaning at 2 or 3 wk of age (2W and 3W groups. respectively). At weaning, piglets were removed from the sow and placed on a commercial starter ration for the first 11 d post-weaning (Phase I diet). At Day 12 post-weaning, pigs were placed on a growing ration for the remainder of the study (Phase II diet). Body weights and blood samples were collected twice weekly from birth until 42 d of age. Serum insulin-like growth factor (IGF)-1, IGF-2, and average daily gain (ADG) were reduced (P < 0.05) in both groups as a result of weaning, whereas serum growth hormone (GH) was elevated (P < 0.05). Earlier weaning resulted in a greater reduction in growth rate and serum IGF-2 values (P < 0.05). Mild reductions in ADG occurred after the Phase I to II dietary change in both weaning groups (P < 0.05), but serum IGF-1 decreased only in the 2W group (P < 0.05). Growth hormone concentrations tended to increase after the change in post-weaning diets (P = 0.07 and 0.16 in 2W and 3W, respectively). Serum thyroxine (T4) and triiodothyronine (T3) levels were unaltered by weaning but declined in both groups after the change in starter diets (P < 0.05). Changes in cortisol concentrations were not associated with weaning or the change in post-weaning diets. With the exception of serum IGF-1 concentrations, which were elevated in the 2W group, growth and endocrine endpoints were equivalent between experimental groups at the end of the study (42 d of age). These results indicate that earlier weaning and changing solid diets can more severely affect patterns of early growth and related hormone secretion, but effective compensatory mechanisms restore normal physiological and physical development.

Animal Feed↗

PubMed1998

Neuroendocrine-immune interactions in the neonate.

Cytokine responses to lipopolysaccharides in neuroendocrine tissues are age- and tissue-dependent in neonatal pigs. Developmental differences in serum and tissue-specific responses are not necessarily equivalent. Lower levels of cytokine gene expression in neuroendocrine tissues of early neonates potentially could influence neuroendocrine and immune responses to infection. The limited information on neuroendocrine-immune responses and interactions in neonatal farm animals presents significant challenges, as well as opportunities for new discoveries and improvements of livestock production.

Acute-Phase Reaction↗

PubMed1998

The biology of leptin: a review.

Leptin, a 16-kDa protein secreted from white adipocytes, has been implicated in the regulation of food intake, energy expenditure, and whole-body energy balance in rodents and humans. The gene encoding leptin was identified by positional cloning and is the mutation leading to the profound obese phenotype of the ob/ob mouse. Exogenous administration of leptin to ob/ob mice leads to a significant improvement in reproductive and endocrine status as well as reduced food intake and weight loss. The expression and secretion of leptin is highly correlated with body fat mass and adipocyte size. Cortisol and insulin are potent stimulators of leptin expression, and expression is attenuated by beta-adrenergic agonists, cAMP, and thiazolidinediones. The role of other hormones and growth factors in the regulation of leptin expression and secretion is emerging. Leptin circulates specifically bound to proteins in serum, which may regulate its half-life and biological activity. Isoforms of the leptin receptor, members of the interleukin-6 cytokine family of receptors, are found in multiple tissues, including the brain. Many of leptin's effects on food intake and energy expenditure are thought to be mediated centrally via neurotransmitters such as neuropeptide Y. Multiple peripheral effects of leptin have also been recently described, including the regulation of insulin secretion by pancreatic beta cells and regulation of insulin action and energy metabolism in adipocytes and skeletal muscle. Leptin is thought to be a metabolic signal that regulates nutritional status effects on reproductive function. Leptin also plays a major role in hematopoeisis and in the anorexia accompanying an acute cytokine challenge. The profound effects of leptin on regulating body energy balance make it a prime candidate for drug therapies for humans and animals.

Animal Husbandry↗

PubMed1997

Expression of luteinizing hormone-releasing hormone and its receptor in porcine immune tissues.

Luteinizing hormone-releasing hormone (LHRH) is the primary regulator of pituitary LH release. However, LHRH has also been identified in extrahypothalamic sites including immune tissues. Accordingly, immunomodulatory properties for LHRH have been suggested. We wanted to determine whether LHRH and its receptor are produced by immune tissues in the pig. First, a cDNA was cloned and sequenced from the porcine hypothalamus that showed 87.5% homology with the human LHRH gene. Internal primers were identified from this sequence for amplifying a 268 bp product by PCR. In addition to the hypothalamus, PCR products reflecting LHRH mRNA were amplified in porcine spleen, thymus, and peripheral blood lymphocyte (PBL) cDNA. LHRH mRNA was not detected in liver, cerebral cortex, or pituitary tissue samples. Primers were designed to amplify a 360 bp fragment of LHRH-receptor cDNA. PCR products reflecting LHRH-receptor mRNA were amplified in pig hypothalamus, pituitary, thymus, spleen and PBL cDNA samples. No such products were amplified in cortex and liver samples. In summary, we report the sequence of a cDNA coding for LHRH and Gonadotropin-RH associated peptide (GAP) in the pig hypothalamus. Additionally, we provide evidence that LHRH and its receptor are synthesized in porcine immune tissues. This leads us to speculate that LHRH may have local, immunomodulatory functions in pigs.

Amino Acid Sequence↗

PubMed1997

Suppression of somatotroph function induced by growth hormone treatment in neonatal pigs.

The effect of recombinant porcine growth hormone (pGH) treatment on pituitary function was evaluated in young pigs. Piglets received intraperitoneal recombinant pGH implants (0.5 mg/d sustained release) or vehicle implants beginning at 3 d of age. Ten piglets were sacrificed at 4 and 6 wk of age (five piglets/treatment group) for the collection of pituitary glands, blood, and liver tissue. Blood samples also were drawn at 3 and 12 d of age. Serum concentrations of GH, prolactin (PRL), thyroid-stimulating hormone (TSH), insulin-like growth factor-1 (IGF-1) and IGF-2 were evaluated. Levels of IGF-1 and IGF-2 mRNA were determined in liver samples. Treatment with GH increased circulating levels of GH and IGF-1 (P < 0.01), but not PRL, TSH, or IGF-2. Hepatic IGF-1, but not IGF-2, mRNA levels were increased by pGH (P < 0.001). Cultured pituitary cells from each animal were challenged with 0.1, 1, and 10 nM GH-releasing hormone (GHRH); 2 nM 8-Br-cAMP; or 100 nM phorbol myristate acetate. The release of GH from cultured pituitary cells was stimulated by all secretagogues (P < 0.001). The secretion of GH, but not PRL or TSH, in culture was inhibited by previous in vivo GH treatment (P < 0.001). Similarly, cellular GH, but not PRL or TSH, content was lower in the GH-implant group (P = 0.005). Cell cultures from 6-wk-old piglets secreted more GH, but not PRL or TSH, than cultures from 4-wk-old piglets (P < 0.05). Likewise, cellular GH, but not PRL or TSH, content was greatest in cultures from 6-wk-old animals (P = 0.002). Piglet growth was not affected by exogenous GH treatment (P = 0.67). These results demonstrate that exogenous pGH treatment selectively down-regulates somatotroph function in young pigs.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1997

Leptin receptor mRNA is expressed in ewe anterior pituitary and adipose tissues and is differentially expressed in hypothalamic regions of well-fed and feed-restricted ewes.

Infertility associated with suboptimal nutrition is a major concern among livestock producers. Recently, much effort has been put into understanding the role of the protein leptin in regulating feed intake and reproduction. Leptin, produced by adipocytes, has receptors in the hypothalamus, but more precise locations of leptin receptor-expressing cell bodies have not been reported in a livestock species. The leptin receptor transcript has several splice variants in the mouse and human, but only the "long-form" product (OBRL) is capable of signal transduction. A partial ovine long-form leptin receptor cDNA was cloned and used to evaluate OBRL mRNA expression within hypothalamic, anterior pituitary, and adipose tissues of ovariectomized adult ewes. Expression was detected in reverse transcription-polymerase chain reaction products of all tissues examined. OBRL mRNA was detected by in situ hybridization in the ventromedial and arcuate nuclei of the hypothalamus. In ewes that had been feed restricted for 3 wk before tissue collection, the expression of OBRL mRNA in these areas was greater (P < 0.05) than that found in well-fed ewes. These findings provide evidence that the full-length leptin receptor is expressed in hypothalamic, anterior pituitary, and adipose tissue (the latter proffering an autoregulatory mechanisms for leptin) and that within the hypothalamus, this receptor form is differentially expressed in well-fed vs. feed-restricted animals.

Adipose Tissue↗

PubMed1997

Somatotroph function in the neonatal pig.

The objective of this study was to evaluate developmental changes in somatotroph function and related gene expression in neonatal pigs. Male piglets were sacrificed at 1, 7, 14, 21, 28, 35, and 42 d of age (8/age group) for the collection of tissue and blood. Serum concentrations of GH were determined. Quantitations of mRNA were performed for pituitary Pit-1, GH, and GHRH receptor. Cultures of pituitary cells from each pig were stimulated with 0, 0.1, 1, or 10 nM GHRH; 2 mM 8-Br-cAMP; or 100 nM phorbol myristate acetate. Elevated serum concentrations of GH were observed at 1 d of age, followed by a pronounced decrease to basal levels thereafter (P < 0.0001). A mild transient increase in circulating GH occurred at Day 28. In vitro GH secretion was significantly stimulated by secretagogue treatments (P < 0.0001). Age-related declines in in vitro GH secretion were observed regardless of if the cells were stimulated by GHRH or by secretagogues that bypass the GHRH receptor (P < 0.001). Similarly, cellular GH content varied with age (P = 0.01). Levels of pituitary GH mRNA (P = 0.01) and GHRH receptor mRNA (P = 0.0002) decreased with age. The quantity of GHRH receptor mRNA was correlated with GH mRNA levels (r = 0.55, P = 0.02), serum GH concentrations (r = 0.55, P = 0.02), and in vitro GH secretion (r = 0.66, P = 0.001). Pituitary Pit-1 mRNA levels at 7 and 14 d of age were significantly elevated relative to all other sampling times (P = 0.0002). Levels of Pit-1 and GH mRNAs were significantly correlated (r = 0.64, P = 0.003). These results demonstrate a strong developmental regulation of somatotrophic function and related gene expression during the early neonatal period of the pig. Age-related decreases in secretory function may be mediated by concurrent mechanisms relating to the expression of the GHRH receptor and of GH.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1997

cDNA cloning and tissue-specific gene expression of ovine leptin, NPY-Y1 receptor, and NPY-Y2 receptor.

The physiological regulation of food intake is a critical factor in both the rate at which an animal grows and its reproductive activity. Recently, progress has been made in elucidating a complex system in which insulin, leptin, and neuropeptide Y function to monitor an animal's energy balance and regulate feed intake and fertility. RNA was extracted from ovine hypothalamic, anterior pituitary, pancreas, and adipose tissue. Using the reverse transcription-polymerase chain reaction. cDNAs were cloned and sequenced for leptin (350 base pairs [bp], GenBank accession number U62123 and 441 bp, GenBank accession number U84247), NPY-Y1 receptor (350 bp, GenBank accession no. U62122) and NPY-Y2 receptor (440 bp, GenBank accession no. U83458). Probes generated from these clones were used to detect mRNA expression within tissues thought to be involved in the coregulation of feed intake and reproduction. Leptin was found to be expressed in sheep adipose tissue. The ovine NPY-Y1 receptor mRNA was detected within the arcuate nucleus and paraventricular nucleus of the hypothalamus, the dentate gyrus of the hippocampus and in pancreatic, anterior pituitary, and adipose tissues. Expression of ovine NPY-Y2 receptor mRNA was detected in the hippocampus and within pancreatic tissue. These observations provide evidence of potential mechanisms that exist for mediating communication between peripheral and central tissues within the insulin-leptin-NPY pathway.

Adipose Tissue↗

PubMed1997

Effects of an intravenous injection of NPY on leptin and NPY-Y1 receptor mRNA expression in ovine adipose tissue.

Neuropeptide Y (NPY) is highly expressed in hypothalami of undernourished and genetically obese animals, and is a potent regulator of food intake and reproduction. Leptin, a protein expressed by adipocytes, has been reported to reduce hypothalamic NPY expression. We recently detected (by ribonuclease protection assay [RPA]) expression of the NPY receptor subtype Y1 (but not Y2) mRNA in adipose tissue. Based on these observations we hypothesized that NPY-Y1 receptors in adipose may represent a peripheral mechanism by which NPY can regulate leptin expression in a direct and rapid manner. To test this hypothesis, adipose samples were biopsied from the tailhead region of 48 +/- 3 kg wether lambs immediately before and 30 min after a single intravenous injection of 50 micrograms porcine NPY ("treated" animals, n = 5), or vehicle ("control" animals, n = 4). Injection of NPY resulted in an increase in expression (P = 0.013; as measured by RPA) of both leptin and NPY-Y1 mRNA. In treated animals, negative correlations were found between response in leptin expression and body weight (r = -0.82, P = 0.092), and between leptin response and initial leptin mRNA levels (r = -0.81, P = 0.097). These data provide evidence of a peripheral mechanism by which NPY may regulate adipocyte expression of both leptin and NPY-Y1 receptor mRNA.

Adipose Tissue↗

PubMed1997

Effects of thermal environment on response to acute peripheral lipopolysaccharide challenge exposure in neonatal pigs.

OBJECTIVE: To evaluate effects of thermal environment on response to acute peripheral lipopolysaccharide (LPS) challenge exposure in neonatal pigs. ANIMALS: 26 neonatal pigs. PROCEDURE: Pigs were assigned to the following treatment groups: 1 warm environment/LPS; 2 warm environment/saline solution; 3 cool environment/LPS; and 4 cool environment/saline solution. For each pig given LPS, 1 littermate of the same sex was given saline solution. Sows with baby pigs were housed in a warm (32 C) or cool (21 C) thermal environment. At 28 days of age, pigs were given 150 micrograms/kg of body weight of Escherichia coli LPS or saline solution intraperitonealy as a control. Rectal temperature and signs of sickness were monitored for 3 hours after LPS administration, when pigs were euthanatized and blood samples were collected to determine serum concentrations of tumor necrosis factor (TNF) alpha and cortisol. To determine in vitro production of TNF alpha, alveolar macrophages were collected by tracheal lavage and incubated for 24 hours at 37 or 41 C, with or without LPS (10 micrograms/ml). RESULTS: Thermal environment had a significant (P = 0.0004) effect on rectal temperature; LPS administration induced a febrile response (P = 0.0007) only in pigs in the warm environment. All LPS-injected pigs developed signs of endotoxemia; serum TNF alpha and cortisol concentrations were significantly increased (TNF alpha, P = 0.003; cortisol, P = 0.0001); there was no significant in vivo thermal effect on serum TNF alpha and cortisol concentrations. LPS-stimulated alveolar macrophages produced significantly less (P = 0.0086) TNF alpha when incubated at 41 C. CONCLUSIONS: Thermal environment can have a significant impact on the response of neonatal pigs exposed to bacterial endotoxins.

Acute-Phase Reaction↗

PubMed1996

Gonadotroph function in 3-week-old gilts reared in a warm or cool thermal environment.

The present study evaluated the effect of a warm (cycling 27-32 degrees C, 50-70% RH) or cool (21 degrees C, 55% RH) thermal environment (TE) on gonadotroph function in 3-week-old gilts (females). Pituitary cells from twelve gilts reared in each TE were cultured at a density of 250,000 cells/1 ml well and exposed to vehicle (culture medium); 1,1, and 10 nM gonadotropin-releasing hormone (GnRH); 2 mM 8-Br-cAMP (cAMP); and 100 nM phorbol myristate acetate (PMA). Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion in culture were stimulated by GnRH and by pharmacological compounds (p < .0001). In vitro LH secretion was approximately three-fold higher in the warm, compared to the cool, TE group (p < .0001). Similarly, cellular LH content in the warm TE exceeded that in the cool TE (p < .005). The in vitro secretion of FSH and cellular FSH content were significantly elevated in the warm TE (p < .02). Serum LH concentrations in the warm and cool TE were 7.01 +/- 1.75 and 2.13 +/- .44 ng/ml, respectively (p < .02). Serum FSH concentrations were 6.38 +/- .53 and 4.59 +/- .28 ng/ml in the warm and cool TE, respectively (p < .01). The results of this study demonstrate that secretory responses of gonadotrophs in early postweaning pigs are influenced by chronic TE exposure. These differences in secretory activity may reflect levels of cellular gonadotropin available for release.

Animals↗

PubMed1996

Lactotroph and somatotroph function in piglets reared in a constant hot environment.

The present study evaluated the effect of rearing in a constant hot (32 degrees C) or cool (21 degrees C) thermal environment (TE) on lactotroph and somatotroph secretory activity in 5-wk-old barrows (castrate males) and gilts (female). Pituitary cells from seven gilts and seven barrows from each TE were cultured at a density of 250,000 cells/1 ml well and exposed to vehicle (culture medium); .1, 1, 10, or 100 nM thyrotropin-releasing hormone (TRH); or .1, 1, or 10 nM growth hormone-releasing hormone (GHRH). Post-receptor cellular stimulation was induced pharmacologically with 2 mM 8-Br-cAMP (cAMP); 100 nM phorbol myristate acetate (PMA); or 59 mM KCl. Prolactin secretion in culture was stimulated by TRH and by pharmacological compounds (p < .0001). In vitro PRL secretion was increased approximately two-fold in the hot environment (p < .02). Similarly, cellular PRL content in the hot TE was twice that in the cool TE (p < .01). The in vitro secretion of growth hormone (GH) was increased by GHRH and by pharmacological compounds (p < .0001), but was unaffected by TE (p > .5). No effects of sex (p > .3) or sex x TE interactions (p > .2) were detected in any endpoint. The results of this study demonstrate that lactotroph, but not somatotroph, secretory activity is enhanced by a constant hot TE in early postweaning pigs. This increase in secretory activity does not appear to be dependent on receptor-mediated cellular activation, but may reflect enhanced levels of cellular PRL available for release.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1996

Identification of insect cell lines by DNA amplification fingerprinting (DAF).

Fingerprint profiles were generated from twenty insect cell lines spanning the Orders, Lepidoptera, Diptera, Coleoptera and Homoptera employing DNA amplification fingerprinting (DAF) with arbitrarily selected primers. The fingerprint pattern is a stable characteristic of the cell line because high and low passages generated the same profile. In addition, insect hosts and homologous cell lines generated similar profiles. All cell lines could be distinguished from each other with the following exceptions: Plutella xylostella (BCIRL-PX2-HNU3) and Mamestra brassicae (IZD-MB-0503) produced identical patterns to Trichoplusia ni (TN-CL1). Also Spodoptera exigua (UCR-SE-1C) produced the same profile as Spodoptera frugiperda (SF9) and the parent cell line IPLB-SF21. All these cases of identical patterns are believed to be due to cross contamination or mislabelling of cultures. DAF will serve as an additional, valuable and reliable technique for the identification of insect cell lines.

Aedes↗

PubMed1996

Relationships of serum insulin-like growth factor II concentrations to growth, compositional, and reproductive traits of swine.

Insulin-like growth factors I and II (IGF-I and -II) are peptide hormones involved in metabolic regulation of growth. The objective of this study was to determine whether IGF-II concentration was predictive of growth, compositional, and reproductive traits of pigs. Forty male and sixty female pigs, divided equally between two locations, were weighed at 3-wk intervals from birth to 21 wk and bled at 9 and 21 wk of age. At each sampling, two blood samples were collected via jugular venipuncture at an interval of at least 1 h. Serum was separated and IGF-I, IGF-II, and growth hormone (GH) concentrations were determined via RIA. Traits measured included age at puberty and first parity litter size for gilts and backfat and longissimus muscle area. Blood was collected from a random sample of 52 progeny from 13 litters at 9 wk of age and serum was assayed for IGF-II concentrations. Effects of age, sex, location, and pig within sex x location on square-root transformed IGF-II concentrations were determined by analyzing data as a splitplot. Performance traits were fitted to a model including the effects of IGF-II concentration and combinations with IGF-I concentration, sex, location, and interactions. Concentrations of IGF-II were greater at 9 than at 21 wk of age (226.7 vs 159.3 ng/mL, respectively; P < .001) but did not differ between sexes. The correlation between serum IGF-II concentrations assayed from samples collected at 9 and 21 wk was .08. The partial correlations between IGF-I and IGF-II concentrations were .33 and .14 at 9 and 21 wk, respectively. The heritability of IGF-II concentration estimated from offspring-midparent regression was .08 +/- .20. Nine-week IGF-II concentration was positively associated with increased weight from weaning to 12 wk (P < .001). However, the sum of 9-wk IGF-I and IGF-II concentrations had a greater relationship to weight and gain in the growing phase than the concentration of either hormone alone. Concentration of IGF-II at 9 or 21 wk alone did not affect backfat thickness, longissimus muscle area, percentage lean, days to 100 kg, weight at 21 wk, age at puberty, or litter size. The sum of IGF-I and IGF-II concentrations was, however, associated with increased backfat and decreased days to 100 kg.

Aging↗

PubMed1996

Overexpression of beta-subunit of thyroid-stimulating hormone in Meishan swine identified by differential display.

Anterior pituitary gland RNA isolated from Meishan (MS) and White Composite (WC) sexually mature boars was compared by a newly developed method of differential expression cloning called differential display. A number of cDNAs were identified that differed distinctly in expression between these breeds. The gene for beta-subunit of thyroid-stimulating hormone (TSH-beta) was initially identified as more highly expressed in MS than in WC boars. Subsequently, RNase protection assays and TSH RIA were used to quantify the magnitude of differences in transcription and translation in both males and females. Mature MS pigs had threefold greater expression of TSH-beta (P < .05) and greater plasma TSH concentrations than mature WC pigs (P < .01). The cDNA cloning and sequence analyses indicate identity in TSH-beta mRNA between MS and WC males. Elevated plasma TSH concentration may contribute MS pigs reaching sexual maturity earlier than WC or other European breeds. The method used in this study provides a useful molecular tool 1) to detect differentially expressed genes, 2) to study genetic variation that occurs at the transcription level between individuals, populations, or breeds; and additionally, 3) to identify candidate genes that control economically important quantitative traits in livestock.

Animals↗

PubMed1995

Effects of recombinant porcine somatotropin on placental size, fetal growth, and IGF-I and IGF-II concentrations in pigs.

The objective of this study was to determine the effects of recombinant porcine somatotropin (rpST) on placental size, fetal growth, and maternal and fetal IGF-I and IGF-II concentrations. Twenty-four pregnant gilts received daily injections of either 1 mL of saline (control) (n = 12) or 5 mg of rpST (n = 12) from d 30 to 43 of gestation. Gilts were slaughtered on d 44 of gestation, reproductive tracts were removed, and fetal weight and length, placental weight, and implantation length were recorded. There was no effect of rpST on fetal or implantation length. Placental weight increased with rpST administration (71.20 +/- 3.52 vs 58.35 +/- 3.41 g; P < .02), as did fetal weight (18.06 +/- .55 vs 16.44 +/- .53 g; rpST vs control, respectively; P < .05). Implantation lengths were partitioned into quartiles to determine the effect of rpST on fetuses with different implantation lengths. The effect of rpST of fetal weight was greater in the first quartile ( < 137.5 mm) than in the fourth quartile ( > 240 mm) (16.04 vs 13.86 g compared with 19.47 vs 18.21 g, respectively). Analysis using a modified Brody curve suggests that the effect of rpST treatment on fetal weight is equivalent to the effect of increasing implantation length by 58.8 mm. Administration of rpST numerically raised IGF-I (P = .07) and IGF-II (P = .12) concentrations in fetal serum. Although maternal serum IGF-I concentrations were similar at d 30, treatment with rpST increased these concentrations over time (77.76, 247.75, 267.85 vs 82.59, 79.59, 77.97 ng/mL on d 30, 37, 43, respectively; P < .001, SE = 14.09). Maternal IGF-II concentrations were also similar at d 30 but decreased over time with rpST treatment (265.78, 219.61, 191.05 vs 285.44, 284.72, 283.05 ng/mL; P < .03, SE = 14.03). Increased maternal IGF-I concentrations may exhibit negative feedback on maternal IGF-II concentrations. The more pronounced effect of rpST on growth in fetuses with shorter implantation lengths suggests that rpST may increase uptake or utilization of nutrients by fetuses. In addition, nutrient transfer across placental membranes may be enhanced by rpST.

Animals↗