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K Tsutsui

Publications and source records attributed to K Tsutsui.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cell-specific expression of the diphtheria toxin A-chain coding sequence under the control of the upstream region of the human alpha-fetoprotein gene.

BACKGROUND AND OBJECTIVES: Development of the system to express a suicide gene selectively in tumor cells is essential for gene therapy. We constructed a plasmid containing the diphtheria toxin A (DTA) fragment linked to human alpha-fetoprotein (AFP) promoter and enhancer, and tested whether it can exert its cytocidal effect selectively on AFP-producing cells. METHODS: The chloramphenical acetyltransferase (CAT) reporter gene or DTA gene was linked to the 5' upstream region of the AFP gene. The plasmids were transfected into AFP-producing or non-producing cells by the lipopolyamine-coated DNA method. Expression of CAT activity and effects on cell growth of transfected cells were assessed. RESULTS: When the AFP-producing cells HuH-7 or HepG2 were cotransfected with CAT reporter plasmid and pAF5.1DTA plasmid, the CAT activity was greatly suppressed. In contrast, cotransfection with pAF5.1DTA-R, the inversely inserted DTA gene, did not inhibit CAT activity. Furthermore, cell growth of HuH-7 cells transfected with pAF5.1DTA plasmid was significantly inhibited compared with HuH-7 cells transfected with DTA-R plasmid. CONCLUSIONS: Our results indicate that selective killing of AFP-producing cells will be attained by introducing the DTA gene linked to the promoter and enhancer region of AFP.

Carcinoma, Hepatocellular↗
PubMed1999

Neural representation of three-dimensional features of manipulation objects with stereopsis.

In the first part of this article, we review our neurophysiological studies of the hand-manipulation-related neurons in the anterior part of the lateral bank of the intraparietal sulcus (area AIP). We describe the properties of visually responsive neurons in area AIP. Object-type visual-dominant neurons responded to the sight of objects and showed selectivity not only for simple geometrical shapes, but also for complex objects such as a knob-in-groove and a plate-in-groove. Some of the object-type visual-dominant neurons showed selectivity for the orientation of the longitudinal axis or the plane (surface) of a plate or a ring. In the second part of this article, we review our study of binocular visual neurons in the caudal part of the lateral bank of the intraparietal sulcus (c-IPS area), in particular, of axis-orientation-selective (AOS) neurons and surface-orientation-selective (SOS) neurons. AOS neurons preferred long and thin stimuli, were sensitive to binocular disparity, and tuned to the axis orientation in three-dimensional (3D) space. SOS neurons preferred broad and flat stimuli and were tuned to the surface orientation in depth. Some SOS neurons responded to a square in a random dot stereogram (RDS) with orientation tuning, suggesting that they encode surface orientation from a disparity gradient. Others responded to solid figure stereograms with orientation disparity and/or width disparity. It was concluded that the c-IPS area is a higher center for stereopsis, which integrates various binocular disparity signals received from the V3 complex and other prestriate areas to represent the neural code for 3D features. It may send projections to the AIP area and contribute to visual adjustment of the shape of the handgrip and/or hand orientation for manipulation and grasping. Neurons of the AIP area may also receive monocular cues of depth from the ventral visual pathway to discriminate the 3D shape of the object of manipulation.

Depth Perception↗
PubMed1999

The hierarchical organization of decision making in the primate prefrontal cortex.

The prefrontal cortex plays an important role in making the association between sensory information and specific behavior. For example, in a complex stimulus response situation, such as the Wisconsin card sorting test, prefrontal patients show difficulty in making appropriate decisions. To understand the neural mechanisms, we recorded prefrontal cell activity while monkeys performed a go/no-go selective attention task where the subjects made a go or no-go response depending on the color or the motion direction of compound visual stimuli (moving colored dots). Groups of cells showed differential activity for go and no-go stimuli (go/no-go activity): some showed the activity either in the color or motion attending condition, and others showed the activity both in the color and motion conditions. Cells of shorter latencies, found mainly in the prefrontal subareas receiving visual input, showed go/no-go activity only when task demands necessitated that the monkeys attended to that cell's preferred visual dimension. We also found cells with longer latencies in the motor-related periarcuate area that showed go/no-go activity regardless of the dimension attended. These results suggest that subareas in the prefrontal cortex play different roles in associating the sensory information with its behavioral meaning and are hierarchically organized to make appropriate decisions in complex tasks.

Animals↗
PubMed1999

Neurosteroid biosynthesis in vertebrate brains.

In mammals, neurosteroids are now known to be synthesized de novo in the brain as well as other areas of the nervous system through mechanisms at least partly independent of the peripheral steroidogenic glands. However, limited information is available on neurosteroids in non-mammalian vertebrates. We therefore have attempted to demonstrate neurosteroid biosynthesis in the brain of birds and amphibians. These vertebrate brains possessed the steroidogenic enzymes, cytochrome P450 side-chain cleavage enzyme (P450scc) and 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3beta-HSD), and produced pregnenolone, pregnenolone sulfate ester and progesterone from cholesterol. Significant seasonal changes in neurosteroids in the brain were observed in seasonally breeding vertebrates. In addition, we attempted to identify the cell type involved in neurosteroidogenesis in mammalian and non-mammalian vertebrates in order to understand the physiological role of neurosteroids. Glial cells are generally accepted to be the primary site for neurosteroid formation, but the concept of neurosteroidogenesis in brain neurons has up to now been uncertain. We recently demonstrated neuronal neurosteroidogenesis in the brain and indicated that the Purkinje cell, a typical cerebellar neuron, actively synthesizes several neurosteroids de novo from cholesterol in both mammals and non-mammals. This paper summarizes the advances made in our understanding of neurosteroid biosynthesis, including neuronal neurosteroidogenesis, in a variety of vertebrate types.

Aging↗
PubMed1999

Expression and activity of 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase in the rat Purkinje neuron during neonatal life.

Recently, we demonstrated that cytochrome P450 side-chain cleavage enzyme (P450scc) occurs in the rat cerebellar Purkinje cell after differentiation and remains during neonatal development and into adulthood. 3Beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3betaHSD) is also an essential enzyme for progesterone biosynthesis not only in peripheral steroidogenic glands but also in the nervous system. In the present study, therefore, the expression of 3betaHSD in the rat cerebellum was investigated during neonatal development and in the adult. RT-PCR analysis showed that the expression of 3betaHSD messenger RNA (mRNA) in the cerebellum was higher at 7-14 days of age than at other times. Biochemical studies together with HPLC analysis revealed that cerebellar slices at 10 days of age converted pregnenolone to progesterone, suggesting enzymatic activity of 3betaHSD. This conversion was significantly reduced by trilostane, a specific inhibitor of 3betaHSD. A specific RIA indicated that progesterone concentrations in the cerebellum were higher at 3 and 10 days of age than at 60 days of age. The progesterone level in the cerebellum was significantly higher than that in plasma at 10 days of age. In contrast, the concentrations in both cerebellum and plasma at 3 and 60 days of age were similar. In the present study, the site of 3betaHSD mRNA expression in the cerebellum was further examined in neonatal and adult rats using in situ hybridization. The cerebellar expression of 3betaHSD mRNA was obscure at 3 days of age, whereas intense expression occurred in Purkinje cells and external granule cells throughout the cerebellum at 10 days of age. 3BetaHSD mRNA was also expressed in Purkinje cells and granule cells at 60 days of age, but a restricted expression was observed along the cerebellar meninges. These results suggest that the steroidogenic enzyme 3betaHSD as well as P450scc are expressed at least in the cerebellar Purkinje cell. The expression of 3betaHSD, however, may increase for a limited period around 10 days of age, unlike P450scc.

17-Hydroxysteroid Dehydrogenases↗
PubMed1999

Pregnenolone, pregnenolone sulfate, and cytochrome P450 side-chain cleavage enzyme in the amphibian brain and their seasonal changes.

To clarify whether the amphibian brain synthesizes de novo neurosteroids, we examined pregnenolone, pregnenolone sulfate ester, and cytochrome P450 side-chain cleavage enzyme (cytochrome P450scc), an enzyme converting cholesterol to pregnenolone, using amphibians. Pregnenolone and its sulfate ester in the brain, gonad, and plasma of Xenopus laevis were measured by a specific pregnenolone RIA. The concentrations of these two steroids in the female brain were significantly larger than those in the ovary and plasma. A similar tendency was evident in the male. In both sexes, pregnenolone and its sulfate ester were concentrated more highly in the cerebellum than in the telencephalon, diencephalon, or midbrain. An immunoreactive protein band of electrophoretic mobility in the proximity of bovine adrenal P450scc was detected in the Xenopus brain as well as the testis by Western blot analysis. Immunohistochemical analysis indicated that Purkinje cells in the Xenopus cerebellum were specifically immunostained with the P450scc antibody. P450scc-like immunoreactive cells were further found in several telencephalic and diencephalic regions, such as the pallium mediale and nucleus preopticus, in the Xenopus brain. A similar localization of P450scc-like immunoreactive cells was evident in Rana nigromaculata, a seasonally breeding amphibian. In the present study, seasonal changes in pregnenolone and its sulfate ester were further examined as a possible physiological change using R. nigromaculata. In both sexes, pregnenolone concentrations in the brain were almost constant during the seasonally breeding cycle. In contrast, the pregnenolone sulfate concentration in the brain was significantly lower in the hibernating quiescent phase and higher in the breeding and postbreeding active phases, independent of the plasma steroid level. These results taken together suggest that the amphibian brain possesses steroidogenic enzyme P450scc and produces pregnenolone and its sulfate ester. Pregnenolone sulfate may function well during the breeding and postbreeding active phases of the year in the seasonal breeder.

Amphibians↗
PubMed1999

Genomic structure of the rat major AP endonuclease gene (Apex) with an adjacent putative O-sialoglycoprotease gene (Prsmg1/Gcpl1) and a processed Apex pseudogene (Apexp1).

Genomic sequencing and chromosomal assignment of the gene encoding rat APEX nuclease, a multifunctional DNA repair enzyme, were performed. An active Apex gene and a processed pseudogene were isolated from a rat genomic library. The active Apex gene consists of 5 exons and 4 introns spanning 2.1 kb. The putative promoter region of the Apex gene lacks the typical TATA box, but contains CAAT boxes and a CpG island having putative binding sites for several transcription factors, such as Sp1, AP-2, GATA-1 and ATF. A putative O-sialoglycoprotease (a homologue of Pasteurella haemolytica glycoprotease, gcp; abbreviated as Prsmg1/Gcpl1) gene consisting of 11 exons and 10 introns spanning 7.3 kb lies immediately adjacent to the Apex gene in a 5'-to-5' orientation. The Apex gene locus was mapped to rat chromosome 15p12 using in situ hybridization. The processed pseudogene (designated as rat Apexp1) has a nucleotide sequence 87.1% identical to that of the rat Apex cDNA, although several stop codons interrupting the coding sequences and multiple nucleotide deletions were observed. The Apexp1 is located in an inactive LINE sequence. Calculation of nucleotide substitution rates suggests that the immediate, active progenitor of Apexp1 arose 23 million years ago and that the non-functionalization occurred 15 million years ago.

Animals↗
PubMed1999

Neurosteroids in the cerebellar Purkinje neuron and their actions (review).

Although the brain is a target site of steroid hormones supplied by peripheral steroidogenic glands, it is now established that the brain itself also synthesizes steroids de novo from cholesterol in a variety of vertebrates. Such steroids synthesized in the brain are called neurosteroids. Because certain structures in vertebrate brains have the capacity to produce neurosteroids, the identification of neurosteroidogenic cells in the brain is essential to understand the physiological role of neurosteroids in brain functions. In the brain, glial cells are considered to play a major role in neurosteroid formation and metabolism. Both oligodendrocytes and astrocytes are the primary site for neurosteroidogenesis. However, the concept of neurosteroidogenesis in neurons in the brain has long been unclear. Recently, we demonstrated neurosteroidogenesis in the Purkinje cell, a typical cerebellar neuron, in mammals and other vertebrates. Pregnenolone sulfate, one of neurosteroids synthesized in the cerebellar Purkinje cell, may contribute to some important events in the cerebellum by modulating neurotransmission. Progesterone, produced as other neurosteroid in this neuron only during neonatal life, may be involved in the promotion of neuronal and glial growth and neuronal synaptic contact in the cerebellum. This review summarizes the advances made in our understanding of neurosteroids, produced in the Purkinje neuron, and their actions.

Aging↗
PubMed1999

Upstream element of the sea urchin arylsulfatase gene serves as an insulator.

Insulator DNAs functionally isolate neighboring genes by blocking interactions between distal cis-regulatory elements and promoters. Here we report that a DNA fragment located in the upstream region of sea urchin, H. pulcherrimus, arylsulfatase (HpArs) gene blocks the interaction of the Ars enhancer when positioned between the enhancer and the target promoter, in an orientation dependent manner. The Ars insulator works only 3' to 5' direction and has no significant stimulatory or inhibitory effects on its own promoter. In transgenic Drosophila, the Ars insulator blocks the interaction between even-skipped stripe enhancer and its target promoter. The insulation mechanism operates also unidirectionally in Drosophila. We also show that the efficiency of transformation of HeLa cells is enhanced when the integrated gene is flanked by the Ars insulator, suggesting the sea urchin insulator overcomes the position-dependent transgene expression in mammalian cells. These results demonstrate that the mechanism of action of the insulator has been conserved throughout evolution.

Animals↗
PubMed1998

Genomic structure and sequence of a human homologue (NTHL1/NTH1) of Escherichia coli endonuclease III with those of the adjacent parts of TSC2 and SLC9A3R2 genes.

Genomic cloning and sequencing of a human homologue (the gene name, endonuclease III-like 1; gene symbol, NTHL1 or NTH1) for Escherichia coli endonuclease III, that is involved in pyrimidine base excision repair, were performed. The sequence covered the entire NTHL1 gene consisting of six exons and five introns spanning 8kb with 5' flanking (8kb) and 3' flanking (3.8kb) regions. Southern blot analysis suggested that the NTHL1 gene exists as a single copy in a haploid genome. The sequenced 5' flanking region lacks typical TATA and CAAT boxes, but contains a CpG island having putative binding sites for several transcription factors such as Ets1 and Sp1. The NTHL1 gene lies immediately adjacent to the tuberous sclerosis 2 (TSC2) gene on chromosome 16p13.3 in a 5'-to-5' orientation. Transcription initiation sites of both NTHL1 and TSC2 genes were suggested to be multiple by 5' RACE experiments. The northern hybridization experiment suggested that both genes are expressed in all tissues, but at different levels. Downstream of the NTHL1 gene, the gene for the regulatory factor 2 (SLC9A3R2/E3KARP; also called OCTS2, TKA-1 and SIP-1) of the solute carrier family 9 (sodium/hydrogen exchanger), isoform A3, lies in a 3'-to-3' orientation. This paper demonstrates for the first time the spatial relationship of these three genes (TSC2, NTHL1 and SLC9A3R2) at the nucleotide level, and the presence of multiple transcription initiation sites of the NTHL1 and TSC2 genes.

Base Sequence↗
PubMed1998

Cloning and characterization of a mouse homologue (mNthl1) of Escherichia coli endonuclease III.

Endonuclease III (endoIII; nth gene product) of Escherichia coli is known to be a DNA repair enzyme having a relatively broad specificity for damaged pyrimidine bases of DNA. Here, we describe the cloning and characterization of the cDNA and the gene for a mouse homologue (mNthl1/mNth1) of endoIII. The cDNA was cloned from a mouse T-cell cDNA library with a probe prepared by PCR using the library and specific PCR primers synthesized based on the reported information of partial amino acid sequences of bovine NTHL1/NTH1 and of EST Data Bases. The cDNA is 1025 nucleotides long and encodes a protein consisting of 300 amino acids with a predicted molecular mass of 33.6 kDa. The amino acid sequence exhibits significant homologies to those of endoIII and its prokaryotic and eukaryotic homologues. The recombinant mNthl1 with a hexahistidine tag was overexpressed in a nth::cmr nei::Kmr double mutant of E. coli, and purified to apparent homogeneity. The enzyme showed thymine glycol DNA glycosylase, urea DNA glycosylase and AP lyase activities. Northern blot analysis indicated that mNthl1 mRNA is about 1 kb and is expressed ubiquitously. A 15 kb DNA fragment containing the mNthl1 gene was cloned from a mouse genomic library and sequenced. The gene consists of six exons and five introns spanning 6.09 kb. The sequenced 5' flanking region lacks a typical TATA box, but contains a CAAT box and putative binding sites for several transcription factors such as Ets, Sp1, AP-1 and AP-2. The mNthl1 gene was shown to lie immediately adjacent to the tuberous sclerosis 2 (Tsc2) gene in a 5'-to-5' orientation by sequence analysis and was assigned to chromosome 17A3 by in situ hybridization.

Amino Acid Sequence↗
PubMed1998

Neural coding of 3D features of objects for hand action in the parietal cortex of the monkey.

In our previous studies of hand manipulation task-related neurons, we found many neurons of the parietal association cortex which responded to the sight of three-dimensional (3D) objects. Most of the task-related neurons in the AIP area (the lateral bank of the anterior intraparietal sulcus) were visually responsive and half of them responded to objects for manipulation. Most of these neurons were selective for the 3D features of the objects. More recently, we have found binocular visual neurons in the lateral bank of the caudal intraparietal sulcus (c-IPS area) that preferentially respond to a luminous bar or place at a particular orientation in space. We studied the responses of axis-orientation selective (AOS) neurons and surface-orientation selective (SOS) neurons in this area with stimuli presented on a 3D computer graphics display. The AOS neurons showed a stronger response to elongated stimuli and showed tuning to the orientation of the longitudinal axis. Many of them preferred a tilted stimulus in depth and appeared to be sensitive to orientation disparity and/or width disparity. The SOS neurons showed a stronger response to a flat than to an elongated stimulus and showed tuning to the 3D orientation of the surface. Their responses increased with the width or length of the stimulus. A considerable number of SOS neurons responded to a square in a random dot stereogram and were tuned to orientation in depth, suggesting their sensitivity to the gradient of disparity. We also found several SOS neurons that responded to a square with tilted or slanted contours, suggesting their sensitivity to orientation disparity and/or width disparity. Area c-IPS is likely to send visual signals of the 3D features of an object to area AIP for the visual guidance of hand actions.

Animals↗
PubMed1998

Age- and region-specific expressions of the messenger RNAs encoding for steroidogenic enzymes p450scc, P450c17 and 3beta-HSD in the postnatal rat brain.

Neurosteroids are now known to be synthesized de novo in the nervous system through mechanisms at least partly independent of peripheral steroidogenic glands. In mammals, the presence of the cholesterol side-chain cleavage enzyme (cytochrome P450scc) and the enzyme 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) has been well established in the brain, whereas limited information has been available on the enzyme 17alpha-hydroxylase/c17, 20-lyase (cytochrome P450c17), which converts pregnenolone to dehydroepiandrosterone, one of the most abundant neurosteroids. In addition, little is known regarding developmental changes in these steroidogenic enzymes during postnatal life. Thus, the pathway of neurosteroid formation in the brain is still incomplete. Therefore, we examined expressions of the messenger RNAs (mRNAs) encoding for three key enzymes, P450scc, P450c17 and 3beta-HSD, in the rat brain at different postnatal ages using RT-PCR analysis. The expression of P450scc mRNA was found throughout the brain at the same level, while the 3beta-HSD mRNA expression was higher in the cerebellum and cerebrum than in other brain regions. The P450c17 mRNA was highly expressed in the mesencephalon. On the other hand, higher expressions of the cerebellar and cerebral 3beta-HSD mRNAs were observed only in neonatal life. In contrast, the expression of P450scc mRNA was relatively constant during neonatal life and in adulthood. A similar constant expression of the P450c17 mRNA was evident in the mesencephalon. Serial Southern hybridization in this study confirmed the specific mRNA expression corresponding to each enzyme. These results suggest that in the postnatal rat the expression of 3beta-HSD or P450c17 mRNA may be age- or region-dependent, unlike the P450scc mRNA expression.

3-Hydroxysteroid Dehydrogenases↗
PubMed1998

Existence and localization of a protein in zebra finch brain with similar structural features as the large subunit of the splicing factor U2AF.

From brains of the adult male zebra finch, we purified a peptide that has a homologous sequence of the large subunit of human U2AF. U2AF is a non-small-nuclear ribonucleoprotein (snRNP) splicing factor required for pre-spliceosome assembly. U2AF consists of a large and a small subunit, whereas only a large subunit is required for in vitro splicing. To show that U2AF large-subunit-like protein exists in the brain of zebra finches, we conducted immunoblot analysis on brain extract, using antiserum against an isolated peptide with primary structures similar to the U2AF large subunit (ppU2AFls). The immunoblot analysis showed that a protein with a molecular weight of about 60 kd reacted with the anti-ppU2AFls-antibody to a putative peptide of the U2AF large subunit. To examine the localization of this protein in the brain, we also conducted immunohistochemical analysis with the anti-peptide. An intense immunoreaction was restricted within the cellular nucleus throughout the brain, suggesting that this protein may contribute to the pre-spliceosome assembly in almost all of the regions of the brain.

Amino Acid Sequence↗
PubMed1998

Radiotherapy combined with transcatheter arterial infusion chemotherapy for locally advanced cervical cancer.

Twenty-four patients with locally advanced cervical cancer were treated with radiation therapy (RT) and transcatheter arterial infusion (TAI) chemotherapy, while 22 patients were treated with RT alone. RT consisted of a combination of external irradiation and high-dose-rate intracavitary brachytherapy. TAI therapy consisted of two sessions using cisplatin and pirarubicin, performed concurrently during the periods of external irradiation. The local-regional control rates at 1 year for the patients treated with RT plus TAI and for those treated with RT alone were 87.5% and 58.3%, respectively (p < 0.05). The 3-year cause-specific survival (CSS) rates for RT plus TAI, and RT alone were 67.1% and 55.9%, respectively (p = n.s.). The 3-year CSS rate for the 14 patients treated with RT and TAI who had well- or moderately differentiated squamous cell carcinoma without pelvic lymph node swelling was 100%, while that for the 19 patients with the same background treated with RT alone was 49% (p < 0.01). Radiation therapy combined with TAI appears to be an effective and safe treatment modality for patients with locally advanced cervical cancer.

Adult↗
PubMed1998

Cytochrome P450 side-chain cleavage enzyme in the cerebellar Purkinje neuron and its neonatal change in rats.

Neurosteroids are de novo synthesized in the nervous system through mechanisms at least partly independent of peripheral steroidogenic glands. However, the concept of neurosteroidogenesis in neurons is not clear in mammalian brains. The present study identified the presence of cytochrome P450scc in the rat Purkinje cell, a typical cerebellar neuron. Immunohistochemical analysis with the antibody against the purified bovine adrenal P450scc showed an immunoreaction restricted to somata and dendrites of the Purkinje cells in adult cerebella. Preadsorbing the antibody with P450scc resulted in a complete absence of the immunoreaction. The antibody against inositol triphosphate receptor, a marker of the Purkinje cell, recognized P450scc-immunoreactive cerebellar cells that showed no immunoreaction with glial fibrillary acidic protein, a specific marker of glial cells. Expression of the P450scc-like protein in the cerebellum was verified by Western blot analysis, and cerebellar P450scc messenger RNA, by RT-PCR analysis in adulthood. On the other hand, P450scc-immunoreactive cells were found to scatter throughout the cerebellum at 0 day of age, before the differentiation of the first Purkinje cells, while the site of expression of this protein was localized only in somata of Purkinje cells at 3 days of age. Immunoreactive dendrites of the Purkinje cell spread into the molecular layer during neonatal development concurrently with its maturation. The intensity of the immunoreaction did not change during neonatal life. Expression of the cerebellar P450scc messenger RNA was also detected after birth, and the level was almost constant during neonatal life. A specific RIA indicated that the pregnenolone concentration was unexpectedly high at 0 day and decreased until 7 days. The total amount of pregnenolone in the cerebellum was almost constant from 0-7 days and increased during 7-21 days concurrently with the cerebellar development. In contrast, the pregnenolone sulfate ester level was low and did not significantly change among the developmental stages. These results suggest that steroidogenic enzyme P450scc appears in the rat Purkinje cell immediately after its differentiation. The expression of this enzyme may remain during neonatal development and in adulthood.

Age Factors↗
PubMed1998

Developmental changes in galanin receptors in the quail oviduct and the effect of ovarian sex steroids on galanin receptor induction.

We have recently isolated an oviposition-inducing peptide from mature quail oviducts identified as avian galanin. This peptide evoked vigorous contractions of the uterine oviduct through binding to receptors located in the uterus. The questions arising from these findings are: what changes occur in galanin receptors in the uterus during maturation, and what is the hormonal factor(s) that induces uterine galanin receptors? Therefore, the present study examined changes in uterine galanin receptors with age and the effect of administration of ovarian sex steroids on galanin receptors in the quail. Immature females reared under long day (LD) photoperiods from 4 weeks of age demonstrated a progressive increase in specific galanin binding per both unit uterine weight and per whole uterus concurrent with uterine development during 4-13 weeks. Scatchard plot analyses of the binding to the uterine preparation showed that the equilibrium dissociation constant (Kd) was about 0.30-0.34 nM regardless of age, and the change in galanin binding during uterine development was due to a change in the number of binding sites. Plasma 17beta-estradiol and progesterone concentrations were almost constant between 4-6 weeks and tended to increase thereafter. Administration of 17beta-estradiol to immature females for 1 week increased not only uterine weight but also specific galanin binding per unit uterine weight, whereas progesterone increased only the binding per unit uterine weight. Both sex steroids also induced an increase in total binding per uterus. Combined administration of 17beta-estradiol and progesterone induced marked increases in the galanin binding, and the effect was not additive but, rather, was synergistic. Scatchard plot analysis showed that the number of binding sites, but not the Kd, was increased by steroid treatment. Administration of 17beta-estradiol or progesterone increased each circulating steroid level to that relatively similar to the maximal levels observed in females exposed to LD. Thus, ovarian sex steroids may contribute at least in part as hormonal factors to galanin receptor induction, which takes place in the uterine oviduct during development.

Age Factors↗