Association of p34cdc2 and cyclin B1 during meiotic maturation in porcine oocytes.

The relative levels and association of p34cdc2 and cyclin B1 have been determined in pig oocytes during meiotic progression from G2 to metaphase II (MII). Fully grown G2-arrested porcine oocytes contained large amounts of free p34cdc2 and extremely small amounts of p34cdc2-cyclin B1 complex which did not increase in amount during the GV stage. Cyclin B1 is not synthesized in measurable quantities until 23 hr after the start of maturation.

Is the inhibitory action of estradiol on luteinizing hormone pulse frequency in anestrous ewes mediated by noradrenergic neurons in the preoptic area?

This study tested the hypothesis that estradiol inhibits luteinizing hormone (LH) pulse frequency in anestrous ewes by increasing the activity of an inhibitory noradrenergic (NE) system that acts in the ovine preoptic area (POA). The effects of estradiol on the release of NE and other neurotransmitters in the POA were determined using intracranial microdialysis. Microdialysis probes (5 mm membrane length) were inserted via chronic guide tubes into the POA.

[Abdominal aortic aneurysm binds less albumin-I-125 the atheromatous aorta].

The causes of abdominal aortic aneurysm are still poorly understood. The author studied the permeability of the aneurysm wall or the aortic wall in 21 patients with abdominal aortic aneurysm or aorto-iliac bypass by comparing 125I-albumin tissue concentrations; The results suggest that albumin crosses the aneurysm wall less easily than that of the atheromatous aorta.

Expression of the genes for the epidermal growth factor receptor and its ligands in porcine oviduct and endometrium.

We have used the reverse transcription-polymerase chain reaction (RT-PCR) to determine whether transcripts for the epidermal growth factor (EGF) receptor and its four known ligands--EGF, transforming growth factor alpha (TGF alpha), amphiregulin (Ar), and heparin-binding EGF (HB-EGF)--are expressed in porcine oviduct and endometrium. We were able to detect mRNA for the EGF receptor, EGF, TGF alpha, and Ar in both the oviduct and endometrium, whereas HB-EGF mRNA was not detectable in either tissue. Through use of an antiserum raised against recombinant pig EGF, expression of EGF was found to be localized to the columnar epithelial cells of the oviduct and to the glandular epithelial cells of the endometrium.

Centrally administered vasopressin modifies stress hormone (cortisol, prolactin) secretion in sheep under basal conditions, during restraint and following intravenous corticotrophin-releasing hormone.

The effects of central (lateral ventricle) injections of vasopressin (2.5, 25 or 250 ng) on cortisol and prolactin release were investigated in castrated male sheep (N = 6) under basal (non-stress) conditions, during 120min of physical restraint and following peripheral injection of ovine corticotrophin-releasing hormone (oCRH). Cortisol and prolactin concentrations in non-stressed sheep were raised significantly (p < 0.

Effect of a novel CCKA receptor antagonist (2-NAP) on the reduction in food intake produced by CCK in pigs.

The effect of a novel CCKA receptor antagonist 2-naphthalene sulphonyl-L-aspartyl-2-(phenethyl)amide, sodium salt (2-NAP) on the reduction of food intake induced by exogenous CCK, administered centrally or peripherally, has been examined in pigs. 2-NAP is hydrophilic and should not readily cross the blood-brain barrier. Intravenous (IV) 2-NAP (20 or 40 mg/kg) injected prior to IV CCK-8S (1 microgram/kg) abolished the inhibitory effect of CCK-8S on operant food intake in hungry pigs.

[Abdominal aortic aneurysm binds less albumin I-125 than the atheromatous aorta].

The causes of abdominal aortic aneurysm are still poorly understood. The author studied the permeability of the aneurysm wall or the aortic wall in 21 patients with abdominal aortic aneurysm or aorto-iliac bypass by comparing 125I-albumin tissue concentrations; The results suggest that albumin crosses the aneurysm wall less easily than that of the atheromatous aorta.

Confocal and fluorescence microscopic study using lectins of the distribution of cortical granules during the maturation and fertilization of pig oocytes.

A study was carried out to determine whether pig cortical granules (CGs) could be visualized using fluorescein isothiocyanate (FITC)-labelled lectins. Following labelling with FITC-labelled peanut agglutinin (FITC-PNA), fluorescent spots were observed that had a distribution during maturation and fertilization entirely consistent with that observed by electron microscopy. For the first 18 h of in vitro maturation, most of the fluorescent spots of FITC-PNA were distributed throughout the cortical cytoplasm.

Inactivation of the murine cftr gene abolishes cAMP-mediated but not Ca(2+)-mediated secretagogue-induced volume decrease in small-intestinal crypts.

The cellular volume of crypts isolated from 2- to 3-week-old mouse small intestine has been measured to assess the capacity of the epithelial cells to respond to secretagogues. Vasoactive intestinal polypeptide (VIP) or carbachol, respectively cAMP- and calcium-mediated secretagogues, produced a reduction crypt volume attributed to KCl loss through channels activated by the agonists. Consistent with the participation of separate chloride channels, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) blocked the carbachol- but not the VIP-induced volume decrease, whilst glibenclamide abolished the VIP effect without affecting the carbachol-induced volume decrease.

Localization of bovine trophoblast protein-1 in the cow blastocyst during implantation: an immunological cryoultrastructural study.

At implantation in ruminants the signal for maintenance of progesterone production by the corpus luteum, essential for a successful pregnancy, is an interferon-like protein (bovine, ovine or caprine trophoblast protein-1; e.g. bTP-1) produced by the blastocyst trophoblast.

Possible models describing enterocyte replacement in mouse Peyer's patch follicle-associated epithelial tissue.

Epithelial cells emerging from intestinal crypts surrounding Peyer's patch lymphoid follicles can be shown in chimaeric mice to adopt a wedge-like formation during migration to a central zone of cell extrusion (Schmidt et al. 1985). Similar tissue taken from normal mice has been used as a model in the present work to investigate how such a pattern of convergent migration might take place.

Enterocyte expression of calbindin, calbindin mRNA and calcium transport increases in jejunal tissue during onset of egg production in the fowl (Gallus domesticus).

1. Quantitative measurements of calbindin mRNA, calbindin protein and calcium uptake have been made in sectioned intestinal villi to determine the location and cellular characteristics of their expression in immature, point of lay and laying chickens. 2.

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate.

1. The ability of myo-inositol polyphosphates to inhibit iron-catalysed hydroxyl radical formation was studied in a hypoxanthine/xanthine oxidase system [Graf, Empson and Eaton (1987) J. Biol.

Localization of oestradiol, progesterone and oxytocin receptors in the uterus during the oestrous cycle and early pregnancy of the ewe.

Uterine tissue samples were collected from 47 ewes at various stages of the oestrous cycle and early pregnancy (until day 21) and during seasonal anoestrus. Cryostat sections were immunostained to determine the localization of oestradiol and progesterone receptors using specific monoclonal antibodies. Oxytocin receptors were localized by autoradiography in sections from the same ewes using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]- vasotocin.

Effects of body weight at sexual maturity and the degree and age of restriction during rearing on the ovarian follicular hierarchy of broiler breeder females.

1. Groups of 18 birds were reared to 10 different body weight targets in a randomised block experiment to assess the effect of body weight and the degree and age of restriction on ovarian function at first egg. 2.

Modification of intra-ovarian follicular distributions in broiler breeder hens by ad libitum or restricted feeding.

1. Ovarian follicles in broiler hens from 3 lines fed ad libitum or food restricted were examined at point of lay and from 2 of these lines at 47 weeks of age. The lines were Ross 1 birds and birds selected to be lean or fat on the basis of their plasma very low density lipoprotein concentrations at 7 weeks of age.

Regulation of insulin-like growth factor binding proteins in young growing animals by alteration of energy status.

The regulation of plasma insulin-like growth factor binding proteins (IGFBPs) by energy status has been assessed in 2-month-old pigs. Energy balance was modified by altering thermoregulatory demand and energy intake, with litter-mates being kept for several weeks at either 35 or 10 degrees C on a high (H) or low (L) level of food intake (where H = 2L); plasma samples were taken 20-24 h after the last meal. The two major forms of circulating IGFBP, as estimated by Western blot analysis, were identified putatively as IGFBP-2 and IGFBP-3 (relative molecular weights of 34 and 40-45 kDa respectively).

Potentiation of insulin-like growth factor-I (IGF-I) activity by an antibody: supportive evidence for enhancement of IGF-I bioavailability in vivo by IGF binding proteins.

The effects of ovine polyclonal antibodies raised against human recombinant IGF-I were investigated in GH-deficient rodents in vivo both in the presence and absence of exogenous IGF-I. Dwarf mice (negligible endogenous serum IGF-I) treated with anti-IGF-I serum which had been pre-incubated with IGF-I exhibited a significantly greater rate of daily weight gain than did mice treated with the same dose of IGF-I alone (P < 0.001) or even a 2.

Local inhibition of nitric oxide synthase activity in the accessory olfactory bulb does not prevent the formation of an olfactory memory in mice.

The putative intercellular transmitter nitric oxide has been suggested to play a role in synaptic plasticity in several models of learning and memory. We have investigated the cellular localisation of nitric oxide synthase in the accessory olfactory bulb of the mouse, using immunohistochemistry and NADPH diaphorase histochemistry. The strikingly high levels of nitric oxide synthase observed in the accessory olfactory bulb were found to be due almost exclusively to its localisation in granule cell interneurons.

Bromocriptine treatment of periparturient goats: long-term suppression of prolactin and lack of effect on lactation.

British Saanen dairy goats (n = 10) were treated with bromocriptine or vehicle from day 147 of pregnancy to day 4 post partum, a treatment duration of 8.8 +/- 1.7 d (mean +/- SEM).

Distribution and cellular localization of vasopressin mRNA in the ovine brain, pituitary and pineal glands.

In this study, in situ hybridization histochemistry was used to determine the regional and cellular localization of vasopressin-neurophysin II (AVP) mRNA in the sheep brain and pituitary with an 35S-labelled synthetic 45-mer oligonucleotide probe complementary to the bovine AVP gene. The highest densities of labelled cell bodies were found in the paraventricular nucleus (PVN), supraoptic nucleus (SON) and suprachiasmatic nucleus (SCN) of the hypothalamus, though such cells were also found in other regions of the diencephalon, including the accessory magnocellular nuclei. Labelled cells were also observed sparsely distributed in every major cortical field as well as in choroid plexus and the pineal gland.