Molecular cloning and tissue distribution of pig transforming growth factor alpha.

Transforming growth factor alpha (TGF alpha) was originally identified as a product of tumour tissues and transformed cells in culture. Although it is now clear that expression of this factor is not restricted to neoplastic cells, there remains relatively little information about the sites of expression of TGF alpha in normal tissues. Therefore, an amplified DNA fragment encoding the pig TGF alpha precursor was cloned by reverse transcription-PCR (RT-PCR) using RNA isolated from normal skin tissue as the template.

Tissue distribution of mRNA for heparin-binding epidermal growth factor.

Heparin-binding epidermal growth factor (HB-EGF) is a recently identified member of the EGF family. Mature HB-EGF is processed from a larger transmembrane precursor which can itself act as a cell-surface receptor for the internalization of diphtheria toxin into eukaryotic cells. However, to date there is no information available on the distribution of HB-EGF in mammalian tissues.

GABA release in the zona incerta of the sheep in response to the sight and ingestion of food and salt.

In order to establish which neurotransmitters may influence the activity of zona incerta neurones in the sheep which respond selectively to the sight or ingestion of food, we have measured the release of amino acid and monoamine neurotransmitters from this region using microdialysis sampling. Co-ordinates for the placement of microdialysis probes in regions of the zona incerta where cells respond to the sight or ingestion of food were first established by making single-unit extracellular recordings. When animals were food-deprived results showed that release of gamma-aminobutyric acid (GABA) was increased in response to the sight and ingestion of food but not of aspartate, glutamate, taurine, noradrenaline, dopamine or serotonin.

Cerebrospinal fluid and plasma concentrations of oxytocin and vasopressin during parturition and vaginocervical stimulation in the sheep.

Simultaneous blood and cerebrospinal fluid (CSF) samples were taken from conscious sheep before, during and after parturition. Concentrations of plasma and CSF oxytocin were significantly elevated during contractions and particularly at birth. Mean prepartum CSF concentrations of oxytocin were around 55% of those found in plasma but postpartum they were up to 2-fold higher than those in plasma.

Human antibody production in transgenic mice: expression from 100 kb of the human IgH locus.

In order to study the requirements for a human antibody repertoire to be engineered in transgenic animals, we have created mouse strains that express human immunoglobulin genes from 100 kb of cosmid DNA. Undisrupted integration of the human DNA in the mouse germ line, encoding germ-line V,D,J and the Cmu constant region, was achieved, and proved sufficient for the production of human IgM in the mouse serum. Co-integration of one cosmid (containing the VH6 gene and a 36-kb region of the J-proximal D cluster) with a second cosmid (containing VH26, a further 38-kb of the D cluster, JH and Cmu) results in V-D-J rearrangements in the transgenic mice, similar to those seen in human DNA, were found only in spleen but not in thymus.

Importance of progesterone and estrogen priming for the induction of maternal behavior by vaginocervical stimulation in sheep: effects of maternal experience.

The effects of treating ovariectomised nulliparous and multiparous ewes with progesterone and estrogen on maternal behavior with or without vagino-cervical stimulation were investigated. Following 48 h of estrogen treatment there was neither evidence for stimulation of maternal behavior, nor a reduction in aggressive behavior, towards lambs by either multiparous or nulliparous ewes compared with control treatment (injections of the oil vehicle). Following 5 min of mechanical vaginocervical stimulation, the multiparous estrogen-treated ewes showed both positive maternal responses (low pitch bleats, licking, sniffing and approaching the lamb) and a reduction in aggression (butts) and negative behavior (withdrawal from the lamb) towards the lambs, whereas the nulliparous ewes showed only a reduction in aggression and negative behavior.

A myo-inositol D-3 hydroxykinase activity in Dictyostelium.

A soluble ATP-dependent enzyme which phosphorylates myo-inositol has been characterized in Dictyostelium. The myo-inositol kinase activity was partially purified from amoebae by chromatography on DEAE-Sepharose and phenyl-Sepharose columns. The product of both the partially purified activity and of a crude cytosolic fraction was myo-inositol 3-phosphate.

Microdialysis measurement of in vivo neuropeptide release.

The application of the microdialysis sampling technique for in vivo measurement of neuropeptide release is discussed. In vitro recoveries of different microdialysis membranes are described for a variety of neuropeptides (ranging from 400 to 4500 MW) as well as their dynamic potential for measuring external concentration changes. In vivo experiments illustrating the use of the technique for measuring release of oxytocin and met-enkephalin from the brain of the conscious sheep, and vasopressin in the blood of the anaesthetised rat are described.

Direct responses in males and correlated responses for reproduction in females to selection for testicular size adjusted for body weight in young male lambs.

Selection based upon testicular diameter adjusted for body weight at 6, 10 and 14 weeks of age was used to produce two lines of sheep, with either high or low testicular size. Ten generations of selection were carried out and the estimate of the realized heritability of the selection criterion was 0.53 +/- 0.

Nucleotide sequences and three-dimensional modelling of the VH and VL domains of two human monoclonal antibodies specific for the D antigen of the human Rh-blood-group system.

The nucleotide sequences were determined for the VH and VL domains of two human IgG1 antibodies, Pag-1 and Fog-B, specific for the D antigen of the Rh-blood-group system. The VH-region genes of the two antibodies were derived from separate germ-line genes within the VH-IV gene family, but both antibodies used the same JH6 gene. The D-region genes differed from each other, and no similarity was found to known D regions.

Ablation of the region anterior and ventral to the third ventricle (AV3V region) in the rat does not abolish the release of oxytocin in response to systemic cholecystokinin.

The effect of peripheral administration of cholecystokinin octapeptide (CCK8) on release of oxytocin and vasopressin in the anaesthetized rat was investigated in sham-lesioned rats and in rats which had received electrolytic ablation of the region anterior and ventral to the third ventricle (AV3V region). CCK8 evoked a repeatable and dose-dependent release of oxytocin, but not vasopressin, into the systemic circulation of both sham and lesioned rats, confirming that in the rat CCK8 is a selective stimulus for oxytocin release, and showing that this release is not significantly impaired by lesions of the AV3V region.

Galactose inhibits lactase expression by mouse jejunal enterocytes.

Present work uses a combination of quantitative cytochemistry and measurements of cell migration rates to describe galactose effects on lactase expression by mouse enterocytes. Mice fed galactose were found to eat less, weigh less and drink more than mice maintained on a low-carbohydrate isocalorific diet. The enterocyte migration rate in these mice was also only one third of that determined in low-carbohydrate-fed animals.

Effects of intracerebroventricular infusions of naltrexone and phentolamine on central and peripheral oxytocin release and on maternal behaviour induced by vaginocervical stimulation in the ewe.

The effects of intracerebroventricular infusions of naltrexone and phentolamine on the ability of vaginocervical stimulation to induce maternal behaviour, and plasma and cerebrospinal fluid (CSF) levels of oxytocin, were measured in oestrogen-primed ewes. Results showed that naltrexone, but not phentolamine, significantly inhibited maternal behaviour following vaginocervical stimulation. Naltrexone also prevented the CSF increase in oxytocin following vaginocervical stimulation but was without effect on plasma levels.

Differential modulation of Ca2+-activated K+ channels in ovine pituitary gonadotrophs by GnRH, Ca2+ and cyclic AMP.

Patch-clamp techniques were employed to examine the effects of cAMP in relation to gonadotrophin-releasing hormone (GnRH) action on Ca2+-activated K+ channels in pituitary gonadotrophs derived from ovine pars tuberalis. GnRH applied extracellularly increased channel openings in cell-attached patches similar to calcium ionophore (A23187), while raising intracellular cAMP concentration with dibutyryl cAMP or forskolin decreased the number of functional channels (Nf) and the open state probability (Po). Both cAMP and the catalytic subunit of cAMP-dependent protein kinase produced similar results when applied to the cytoplasmic membrane face of inside-out patches, and the effect of cAMP was abolished by the protein kinase inhibitor.

The influence of central hypersomotic solutions on drinking and vasopressin release following peripheral hyperosmotic NaCl in the minipig.

The drinking and lysine vasopressin (LVP, porcine vasopressin) responses were measured in minipigs given simultaneous intracarotid (i.c.) (1.

The class II genes of the rat MHC.

Genes that encode class II Ag from the MHC of the rat, the RT1 region, have been isolated as a series of cosmid clones. The cosmids define two clusters, each of which contains three identifiable sequences; one homologous to alpha-chain and two to beta-chain genes. Both the serologically identified rat class II Ag have been expressed in mouse L cell fibroblasts after the introduction of each alpha-chain gene along with a beta-chain gene from the same cluster.

Naloxone affects the release of cortisol, but not of vasopressin or oxytocin, in dehydrated sheep.

Ovariectomized ewes (N = 7) were dehydrated for 24 h and then given iv injections of saline vehicle or 8 or 64 mg naloxone hydrochloride in saline. Blood samples were taken by jugular venepuncture before and after dehydration and at intervals during the 90 min period directly following naloxone treatment. Plasma concentrations of AVP, OT and cortisol were measured by radioimmunoassay.

Endogenous opioid actions and effects of environmental disturbance on parturition and oxytocin secretion in rats.

Blood samples were taken from conscious, chronically-catheterized rats during parturition for measurement of oxytocin by specific radioimmunoassay. After the birth of the 3rd pup, rats were allowed to remain in their nesting cage (undisturbed rats) or were transferred for 45 min to a glass bowl (disturbed rats); at the time of transfer, rats were given an i.v.

Changes in the feedback control of gonadotrophin secretion in ewes from lines selected for testis size in the ram lamb.

The dynamics of FSH and LH secretion were studied in sheep genetically selected for High (H) and Low (L) rates of testis growth. Gonadotrophin secretion had previously been shown to be affected in the ram lamb with H-line lambs more sensitive to steroid feedback than L. While there were significant differences in mean LH concentrations during the luteal and follicular phases of the oestrous cycle, mean LH values were essentially similar in the two lines in response to ovariectomy, the effect of oestradiol implants on the response to ovariectomy and the response to LHRH.