Immunoreactive luteinizing hormone-containing neurons in the brain of the white-footed mouse, Peromyscus leucopus

The distribution of immunoreactive LH in the brain of the white-footed mouse (Peromyscus leucopus) was determined using immunocytochemical procedures. Immunoreactive fibers are located in the hypothalamus, preoptic area, septum and amygdala. Stained cell bodies are seen in the arcuate nucleus and preoptic area. Gonadectomy enhances staining for LH in the brain.     

Immunocytochemical localization of GnRH (gonadotropin releasing hormone) systems in the brain of a marine teleost fish,the sole

Summary The GnRH system was studied in the brain of the sole by immunocytochemistry (peroxidase-antiperoxidase method) (PAP) using antibodies to synthetic salmon GnRH (s-GnRH). Two centers containing immunoreactive cell bodies were observed in the forebrain, one located at the junction between the olfactory bulbs and the telencephalon and the other in the preoptic area. Numerous immunoreactive fibers were found, especially in the telencephalon, hypothalamus, pituitary, optic tectum and retina.     

Studies on the modulation of the desensitization of the pituitary gland by luteinizing hormone-releasing hormone in the ovariectomized rat

Summary In ovariectomized rats the desensitization of the LH cells in vivo, which develops during constant rate infusion of LHRH, 1) does not depend on a concomitant depletion of the pituitary LH stores, 2) proceeds normally when the hypothalamo-pituitary connection has been severed and 3) is a process in which LH itself is not involved.     

Copper and zinc dismetabolism in the mouse brain upon chronic cuprizone treatment

Recent reports describe successful treatment using copper chelation therapy in neurodegenerative animal models. However, the success claimed for chelation therapy in neurodegenerative diseases is still rather controversial. To acquire new information on copper metabolism/homeostasis, we utilized cuprizone, a very sensitive and selective copper-chelating agent with well-known neurotoxic properties, as a relevant chemical model in mice. Upon cuprizone treatment, mice developed a pronounced astrocytosis, with brain oedema and spongiosis characterised by vacuolisations of the neuropil predominantly in the white matter. In addition, cuprizone treatment severely altered copper and zinc homeostasis in the central nervous system (CNS) as well as in all other tissues examined, with increasing metal ion concentrations particularly in the CNS. Concomitant with this increase in the Cu and Zn concentration in the brain, metallothionein-I and -II were also highly immunoreactive in astrocyte, consistent with the astrocytosis and demyelination observed in our and other laboratories.Received 23 February 2005; received after revision 3 May 2005; accepted 13 May 2005     

Influence of diet on plasma tryptophan and brain serotonin levels in mice

Summary Groups of mice were maintained for up to 78 weeks on tryptophan restricted, protein restricted and control diets. Plasma tryptophan levels were significantly reduced by both forms of dietary restriction. Brain serotonin levels were significantly reduced only in mice on the tryptophan restricted diet, but not for mice on the protein restricted diet. The protein-restricted diet contains less of the large neutral amino acids which compete with tryptophan to enter the brain. It is known that protein restriction and tryptophan restriction extend lifespan. The results presented here suggest that extension of lifespan and lowering of brain serotonin are not related.     

Number of dopamine neurons predicts prolactin levels in two inbred mouse strains

Summary Mice of the BALB/cJ strain have more dopamine neurons than mice of the CBA/J strain. We now report that BALB/cJ mice have less circulating and pituitary prolactin than CBA/J mice, a relationship expected from the difference in tuberoinfundibular dopamine neuron number.     

Pheromone binding proteins of the mouse,Mus musculus

Proteins of the Major Urinary Complex of the adult male mouse (Mus musculus) selectively bind the male pheromones 2-(sec-butyl)thiazoline and dehydro-exo-brevicomin, and concentrate them in urine.     

Hormonal induction of steroid sulphatase in the mouse

Summary By comparing steroid sulphatase levels per se, and also ratios to -galactosidase, in 6 sets of mice — normal females, entire and castrated males both with and without exogenous testosterone administration — we obtained support for the contention that induction of this enzyme is in part controlled by male hormones.     

Gentic control of erythrocyte esterase (Es-1) in the pinon mouse,Peromyscus truei (Shufeldt)

Zusammenfassung Kreuzungsversuche und elektrophoretische Analyse der Erythrocytenesterase bei der MausPeromyscus truei zeigten, dass die Homozygoten je eine Enzymbande mit unterschiedlichen Beweglichkeiten aufweisen, während bei den Heterozygoten beide Enzymbanden vorkommen, was mit der Annahme der Abspaltung von zwei kodominanten Allelen eines einzigen autosomalen Locus übereinstimmt.

---

---

Supported by Faculty Research Grant No. 35064 from North Texas State University awarded toZimmerman.     

Development of the innervation of the urogenital complex in the fetal mouse

Summary The developing urogenital complex of the fetal mouse was studied by means of silver impregnation and electron microscopy. These studies showed that: 1) the mesonephric field is innervated during prenatal stages (Wolffian nerve); 2) nerve penetration precedes the differentiation of the gonads and related ducts; and 3) the Wolffian nerve arises during the earliest stages from the first pair of abdominal rami communicantes. The identity between the fetal Wolffian nerve and the nerve of the suspensory ligament (higher pathway) of the adult is discussed.     

Juvenile hormone degradation in brain and corpora cardiaca-corpora allata complex during the last larval instar ofGalleria mellonela (Lepidoptera,Pyralidae)

Summary Time course analysis of juvenile hormone degradation in the brain and the corpora cardiaca-corpora allata complex shows that during the first two days of the last larval instar the juvenile hormone degradation is very low. Starting from the third day up to the seventh day a continuous increase of esterase activity is observed.     

Development of dopaminergic neurons in the mammalian brain

Dopaminergic neurons in the mammalian brain have received substantial attention in the past given their fundamental role in several body functions and behaviours. The largest dopaminergic population is found in two nuclei of the ventral midbrain. Cells of the substantia nigra pars compacta are involved in the control of voluntary movements and postural reflexes, and their degeneration in the adult brain leads to Parkinson’s disease. Cells of the ventral tegmental area modulate rewarding and cognitive behaviours, and their dysfunction is involved in the pathogenesis of addictive disorders and schizophrenia. Because of their clinical relevance, the embryonic development and maintenance of the midbrain dopaminergic cell groups in the adult have been intensively studied in recent years. In the present review, we provide an overview of the mechanisms and factors involved in the development of dopaminergic neurons in the mammalian brain, with a special emphasis on the midbrain dopaminergic population. Received 17 August 2005; received after revision 28 September 2005; accepted 21 October 2005     

Effects of ovariectomy on removal of collagen bundles in the postpartum uterus of the mouse

Ovariectomy before and after parturition did not influence the rate of postpartum involution and did not affect the removal of collagen bundles in the endometrium during the first three postpartum days.     

Distribution of intravenously administered acidic and basic fibroblast growth factors in the mouse

Summary Iodinated acidic or basic fibroblast growth factor (aFGF or bFGF) were separately injected into adult mice to follow their distribution in the main organs of the animals. Iodinated FGFs intravenously injected into mice cleared from blood with aT _1/2 of 30 s. They mainly bound to kidney, liver and spleen. The binding of FGFs to these organs was maintained when the latter were washed with a physiological buffer containing 0.15 M NaCl, but it was eliminated when the buffer contained 2 M NaCl. Simultaneous injections of the FGFs together with increasing doses of heparin weakened the binding of FGF to vessels in a dose-dependent manner.     

Effects of multiple injections of luteinizing hormone-releasing hormone in the induction of pregnancy in androgenized female rats

Summary A study of the effect of cyclic (every 4 days) administration of gonadotropin releasing hormone on reproductive performance of the androgenized female rat was carried out. The responses measured were indirect indices of increased gonadotropin output; ovulation rate, uterine decidualization, mating and implantation.     

Comparison of the in vitro development of mouse single blastomeres with and without the zona pellucida

Summary No difference was observed during in vitro development between mouse single blastomeres with and without the zona, pellucida, isolated from 2- and 4-cell stage eggs.     

Expulsion of the placenta from the uterus is the principal initiator for collagen degradation in mouse uterus

In unilaterally pregnant mice, collagen degradation in the non-pregnant uterine horn was not initiated by removal of the fetus only but by removal of both the fetus and placenta. The results indicate that expulsion of the placenta from the uterus is a principal factor in the initiation of the process of collagen degradation simultaneously in the whole uterus.     

Comparison of the time courses of luteinizing hormone (LH) secretion rates during continuous stimulation by LH-releasing hormone (LH-RH) in vivo and in vitro

Summary The patterns of LH secretion during constant stimulation of the pituitary glands of estradiol-treated ovariectomized rats with a maximally stimulating amount of LH-RH in vivo and in vitro correspond with each other qualitatively and quantitatively. In vitro the changes with time of the LH secretion rate are somewhat retarded, especially the occurrence of desensitization.     

The effect of nicotine on blood pressure in the genetically hypertensive mouse

Summary Mice genetically selected for high and low blood pressure were exposed to nicotine via a single injected dose or addition to drinking water for 52 weeks. In the acute study, the response of mice with high blood pressure was a statistically significant increase in blood pressure. In the chronic study the pattern of response to nicotine ingestion was similar for mice with high blood pressure and those with low. Both lines responded with an increase in blood pressure after 6 weeks followed by a decrease to below baseline blood pressure at 12 weeks.This research was supported in part by an allocation from the General Research Fund of the University of Kansas.     

Identification of the bioactive peptide PEC-60 in brain

PEC-60 is a 60-residue peptide originally isolated from pig intestine. It inhibits glucose-induced insulin secretion from perfused pancreas in a hormonal manner and also has biological activity in the immune system. PEC-60-like immunoreactive material has been reported in catecholamine neurons of the central and peripheral nervous systems, but the peptide has not been identified from that material. We have now isolated PEC-60 from pig and rat brains with a method that combines column purification procedures with the specificity of a radioimmunoassay and the sensitivity of mass spectrometry to directly identify the peptide. The results show that PEC-60, like many other peptides, is expressed in the gastrointestinal tract and the central nervous system. The specific regional brain distribution and interaction with classical neurotransmitters raise the possibility that PEC-60may play a role in the central nervous system disorders involving dopamine dysregulation. Received 6 December 2002; received after revision 10 December 2002; accepted 11 December 2002 RID="*" ID="*"Corresponding author.