The uterine expression of leukemia inhibitory factor (LIF) is essential for embryo implantation in the mouse. Here (EGF) or an EGF-like molecule has been implicated in regulating endometrial cell proliferation (5) and in some strains of mice embryonic expression of the EGF receptor is essential for development of the peri-implantation embryo (6). Colony-stimulating factor-1

The neurotransmitter serotonin (5-HT) plays an important role in both the peripheral and central nervous systems. The biosynthesis of serotonin is regulated by two rate-limiting enzymes, tryptophan hydroxylase-1 and -2 (TPH1 and TPH2). We used a gene-targeting approach to generate mice with selective and complete elimination of the two known TPH isoforms. This resulted in dramatically reduced central 5-HT levels in Tph2 knockout (TPH2KO) and Tph1/Tph2 double knockout (DKO) mice; and substantially reduced peripheral 5-HT levels in DKO, but not TPH2KO mice. Therefore, differential expression of the two isoforms of TPH was reflected in corresponding depletion of 5-HT content in the brain and periphery. Surprisingly, despite the prominent and evolutionarily ancient role that 5-HT plays in both vertebrate and invertebrate physiology, none of these mutations resulted in an overt phenotype. TPH2KO and DKO mice were viable and normal in appearance. Behavioral alterations in assays with predictive validity for antidepressants were among the very few phenotypes uncovered. These behavioral changes were subtle in the TPH2KO mice; they were enhanced in the DKO mice. Herein, we confirm findings from prior descriptions of TPH1 knockout mice and present the first reported phenotypic evaluations of Tph2 and Tph1/Tph2 knockout mice. The behavioral effects observed in the TPH2 KO and DKO mice strongly confirm the role of 5-HT and its synthetic enzymes in the etiology and treatment of affective disorders.

5-Hydroxytryptamine (serotonin) (5-HT) is a neurotransmitter with both central and peripheral functions, including the modulation of mood, appetite, hemodynamics, gastrointestinal (GI) sensation, secretion, and motility. Its synthesis is initiated by the enzyme tryptophan hydroxylase (TPH). Two isoforms of TPH have been discovered: TPH1, primarily expressed in the enterochromaffin cells of the gastrointestinal tract, and TPH2, expressed exclusively in neuronal cells. Mice lacking Tph1 contain little to no 5-HT in the blood and GI tract while maintaining normal levels in the brain. Because GI 5-HT is known to play important roles in normal and pathophysiology, we set out to discover and characterize novel compounds that selectively inhibit biosynthesis of GI 5-HT. Here, we describe two of a series of these inhibitors that are potent for TPH activity both in biochemical and cell-based assays. This class of compounds has unique properties with respect to pharmacokinetic and pharmacodynamic effects on GI serotonin production. Similar to the Tph1 knockout results, these TPH inhibitors have the ability to selectively reduce 5-HT levels in the murine GI tract without affecting brain 5-HT levels. In addition, administration of these compounds in a ferret model of chemotherapy-induced emesis caused modest reductions of intestinal serotonin levels and a decreased emetic response. These findings suggest that GI-specific TPH inhibitors may provide novel treatments for various gastrointestinal disorders associated with dysregulation of the GI serotonergic system, such as chemotherapyinduced emesis and irritable bowel syndrome.5-Hydroxytryptamine (serotonin) (5-HT) is a neurotransmitter with both synaptic and paracrine activities that modulates central and peripheral functions through action on neurons, smooth muscle, and other cell types. It is synthesized from tryptophan by the sequential actions of tryptophan hydroxylase (TPH) and aromatic amino acid decarboxylase. Only one form of TPH was known to exist until Walther et al. (2003a) published a second distinct TPH-encoding gene. The originally identified isoform was renamed TPH1, and the newly discovered isoform was designated TPH2. The two enzymes share an overall identity of ϳ70%, and they are both ϳ50% identical to the other two members of the aromatic amino acid hydroxylase family, phenylalanine and tyrosine hydroxylases. Tph1 is primarily expressed in the pineal gland and non-neuronal tissues, such as enterochromaffin (EC) cells of the gastrointestinal (GI) tract (Côté et al., 2003;Patel et al., 2004). In contrast, Tph2 is expressed exclusively in neuronal cells, such as the dorsal raphe and myenteric plexus (Côté et al., 2003;Walther et al., 2003a;Patel et al., 2004).5-HT is involved in the control and modulation of multiple physiological and psychological processes. In the central nervous system (CNS), 5-HT regulates mood, appetite, and other Article, publication date, and citation information can be found at

The role of endometrial and embryonic integrins during implantation remains unresolved although work in animal models and in humans supports their involvement in this process. Temporal and spatial distribution of the alpha(v)beta(3) integrin on both embryo and endometrium in women and mice coincides with the time of initial attachment during implantation. In mice, the endometrial and embryonic alpha(v)beta(3) integrin is present at the time of implantation, as shown by reverse transcription-polymerase chain reaction and immunohistochemistry. In situ hybridization demonstrates the presence of the alpha(v)beta(3) integrin on the subluminal stromal cells of the uterus. Functional blockade of this integrin on the day of implantation by intrauterine injection of neutralizing monoclonal antibodies against alpha(v) or beta(3) integrin subunits, arg-gly-asp (RGD)-containing peptides, or of the disintegrin echistatin, reduced the number of implantation sites compared to controls receiving BSA. These studies demonstrate that, like the human, the murine alpha(v)beta(3) integrin is expressed at the time of implantation in the endometrium and on the blastocyst, and may play a critical role in the cascade of events leading to successful implantation.

We have used a rat pachytene spermatocyte cDNA expression library to clone TBP‐1 (for tat‐binding protein‐1; designated rat testis TBP‐1 [rtTBP‐1]), a new member of the family of putative ATPases associated with the 26S proteasome complex. The 1.63 kb rtTBP‐1 cDNA encodes a 49 kDa protein with 99% amino acid identity to human TBP‐1 protein. rtTBP‐1 protein contains a heptad repeat of six leucine‐type zipper fingers at the amino terminal end and highly conserved ATPase and DNA/RNA helicase motifs towards the carboxyl terminal region. Chromatofocusing fractionation of rat testis sucrose extracts demonstrates that the encoded product, recognized by an antiserum raised to the first 196 amino acids of human TBP‐1, consists of a protein triplet with a molecular mass range of 52‐48 kDa and acidic pI (5.0–5.9). An identical immunoreactive triplet was detected by immunoblotting in extracts of fractionated pachytene spermatocytes, round spermatids and epididymal sperm. In situ hybridization using digoxigenin‐labeled antisense RNA probes shows a predominant distribution of specific mRNA in the seminiferous epithelial region occupied by elongating spermatids and primary spermatocytes. Indirect immunofluorescence and immunogold electron microscopy studies show that rtTBP‐1 immunoreactive sites colocalize with α‐tubulin‐decorated manchettes of elongating spermatids. In addition, rtTBP‐1 immunoreactivity was detected in fibrillar and granular cytoplasmic bodies typically observed in spermatocytes and spermatids as well as in association with paraaxonemal mitochondria and outer dense fibers of the developing spermatid tail. Results of this study indicate that rtTBP‐1 is a member of the highly evolutionary conserved TBP‐1‐like subfamily of putative ATPases, sharing regions of identity—including ATP‐binding sites—with several subunits of the 26S proteasome, known to be involved in the ATP‐dependent degradation of ubiquitin‐conjugated proteins. Mol. Reprod. Dev. 48:77–89, 1997. © 1997 Wiley‐Liss, Inc.