Baboon Uterus Research Articles

Livebirth and utero-placental insufficiency in Papio hamadryas baboons with uterus angiosome perfused by bilateral utero-ovarian microsurgical anastomoses alone.

Can the baboon uterus support a gestation to livebirth with an angiosome using microsurgically anastomosed utero-ovarian vessels and lacking uterine arteries and veins? Our angiosome model allows healthy livebirth albeit with risk of fetal growth restriction and stillbirth. Uterine transplant can provide livebirth in humans, but requires a living donor to undergo a prolonged laparotomy for hysterectomy. In an attempt to avoid the time-consuming dissection of the uterine vein, our group has previously shown maintenance of baboon uterine menstrual function after ligation of the uterine vein and after ligation of both the uterine artery and uterine vein. In a 19-month timespan, three baboons underwent laparotomy to surgically alter uterine perfusion, and pregnancy outcomes were monitored after spontaneous mating in a breeding colony. Three nulligravid female Papio hamadryas baboons in a breeding colony underwent laparotomy to ligate uterine arteries and veins along with colpotomy and cervico-vaginal anastomosis. During the same surgery, the utero-ovarian arteries and veins were microsurgically transected and re-anastomosed to themselves. Intraoperative organ perfusion was confirmed with laser angiography. After a recovery period, monitoring of menstrual cycling via menstrual blood flow and sex-skin cycling occurred, as well as uterine viability via sonography and cervical biopsy. Each baboon was released to the breeding colony for spontaneous mating and pregnancies dated by menstrual calendar and compared with early ultrasound. Delivery outcomes were monitored in each including neonate weight and placental pathology. In the event of a stillbirth, the animal was returned to the breeding colony for repeat mating attempts. After achieving a livebirth, the maternal baboon was removed from the study. Each baboon in the trial underwent successful surgery with all uteri demonstrating viability and return of menstrual function within 10 weeks of surgery. Pregnancies occurred within two menstrual cycles in breeding colony. Baboons one and two initially had vaginal breech stillbirths, both with appearance of placental insufficiency, and one with fetal growth restriction. Baboon three underwent scheduled cesarean delivery resulting in a normally grown livebirth. Baboon one had a subsequent pregnancy resulting in a livebirth via cesarean delivery. Stillbirth in two of four gestations, and fetal growth restriction in one of four, are the largest concerns in our perfusion model. It remains uncertain whether the stillbirths resulted from placental insufficiency, or birth trauma from breech deliveries. The success of two livebirths warrants further attempts at improving consistency of our proposed uterine angiosome. This may allow living uterine donors to undergo less-invasive and shorter donor hysterectomy procedures. The study had no external sponsors, and was supported by the Cleveland Clinic Foundation. Some equipment was loaned without cost to the research team including a laser angiography system courtesy of Novadaq Technologies, Inc. (Missaugua, ON, Canada) and a surgical microscope courtesy of DB Surgical (Coral Springs, FL, USA). B.B., K.A., M.S., K.R., M.M., P.F.E., A.T. and T.F. have no conflicts of interest. M.L.S. and S.Z. report activity as consultants for Medtronic-Covidien, and S.Z. also is a consultant to Applied Medical.

Cross-Species Withdrawal of MCL1 Facilitates Postpartum Uterine Involution in Both the Mouse and Baboon

A successful postpartum involution permits the postnatal uterus to rapidly regain its prepregnancy function and size to ultimately facilitate an ensuing blastocyst implantation. This study investigates the molecular mechanisms that govern the initiation of the involution process by examining the signaling events that occur as the uterus transitions from the pregnant to postnatal state. Using mouse and baboon uteri, we found a remarkable cross-species conservation at the signal transduction level as the pregnant uterus initiates and progresses through the involution process. This study originated with the observation of elevated levels of caspase-3 activation in both the laboring mouse and baboon uterus, which we found to be apoptotic in nature as evidenced by the concurrent appearance of cleaved poly(ADP-ribose) polymerase. We previously defined a nonapoptotic and potential tocolytic role for uterine caspase-3 during pregnancy regulated by increased antiapoptotic signaling mediated by myeloid cell leukemia sequence 1 and X-linked inhibitor of apoptosis. In contrast, this study determined that diminished antiapoptotic signaling in the postpartum uterus allowed for both endometrial apoptotic and myometrial autophagic episodes, which we speculate are responsible for the rapid reduction in size of the postpartum uterus. Using our human telomerase immortalized myometrial cell line and the Simian virus-40 immortalized endometrial cell line (12Z), we demonstrated that the withdrawal of antiapoptotic signaling was also an upstream event for both the autophagic and apoptotic processes in the human uterine myocyte and endometrial epithelial cell.

Feasibility of LNG-IUS in a baboon model

BackgroundThe baboon (Papio hamadryas anubis) is an attractive model for intrauterine contraception research due to anatomic similarity to the human. Although non-human primates have previously been used for intrauterine contraception research, it was unknown whether modern intrauterine devices (IUDs) can be placed in an anatomically similar position in the baboon. This study sought to determine whether human-use IUDs could be seated correctly in the uterus of the baboon. Study DesignThe levonorgestrel-releasing intrauterine system (LNG-IUS) was placed ex vivo into two baboon uteri collected at necropsy and in three living, reproductively proven baboons. ResultsCorrect placement of human-use IUDs in the baboon was confirmed by both MRI and ultrasound. This study establishes that a LNG-IUS can be inserted into the baboon uterus and maintained without clinically adverse effects for at least 6 months. The positioning of the device is similar to positioning found in women. ConclusionThese findings provide important support for studying IUD safety and efficacy in the baboon.

Decidual Heparanase Activity Is Increased During Pregnancy in the Baboon (Papio anubis) and in In Vitro Decidualization of Human Stromal Cells1

Implantation is a complex process involving interactions between the embryo and the uterus. Adhesion, remodeling of the maternal vasculature, and decidualization are crucial events necessary for successful implantation to occur. Heparanase (HPSE), an endo-beta-D-glucuronidase, cleaves heparan sulfate at specific sites, leading to release of growth factors that may be involved in decidualization and remodeling of the maternal vasculature. HPSE also can function as a cell adhesion molecule. The aim of this study was to determine the expression of HPSE in the uteri of nonpregnant and pregnant baboons as well as in human stromal fibroblasts decidualized in vitro. We examined the localization and expression of HPSE using immunohistochemistry, Western blotting, RT-PCR, and activity assays. In nonpregnant baboon uteri, HPSE expression was localized to the apical surface of the glandular epithelia and in glandular secretions. However, in pregnant baboon uteri, HPSE was localized primarily in decidua. Uteri obtained at midpregnancy had higher heparanase activity compared with the nonpregnant uteri. A slight increase in HPSE expression was observed in human stromal fibroblasts decidualized in vitro. HPSE and HPSE2 mRNA transcripts were present in both decidualized tissue and cells. Increases in heparanase activity in the decidua from pregnant baboon uteri compared with tissue from nonpregnant animals and in human stromal fibroblasts decidualized in vitro suggest that HPSE plays a role in extracellular matrix remodeling and in increasing heparin-binding growth factor release during embryo implantation.

Compartmental distinctions in uterine Muc-1 expression during early pregnancy in cynomolgous macaque (Macaca fascicularis) and baboon (Papio anubis)

Loss of the transmembrane mucin, Muc-1, is a molecular correlate of the acquisition of uterine receptivity to embryo adhesion in most species examined. In macaques, two distinct adhesion events occur at opposite sides of the uterus. Attachment to the secondary site is delayed relative to the primary site. The aim was to determine if Muc-1 is removed at secondary sites prior to trophoblast attachment. We examined Muc-1 expression in the uteri of cynomolgus macaque and baboon during early implantation by immunocytochemistry. Luminal epithelia were devoid of Muc-1 at all stages examined at both primary and secondary adhesion sites. Loss of Muc-1 in luminal epithelia was found to be maternally determined, accompanied membrane transformation in both macaque and baboon, and at secondary implantation sites, preceded trophoblast attachment. In contrast, glandular epithelia in pregnant macaques exhibited a temporal and compartmentalized gradient of Muc-1 loss confined to the implantation sites. Glandular epithelia in the pregnant baboon uterus were uniformly negative for Muc-1. Restriction of the Muc-1 loss in glandular epithelia to conceptual cycles may reflect the fundamental distinctions among epithelia of the various uterine compartments and the differential modulation of Muc-1 that occurs within these compartments in conceptual and non-conceptual cycles.

Characterization of the concentration gradient of prostaglandin H synthase 2 mRNA throughout the pregnant baboon uterus.

The present study was designed to determine the effect of the spatial gradient from the cervix to the uterine fundus on the control of local prostaglandin H synthase (PGHS) 2 mRNA expression. We performed total cesarean hysterectomies during the last trimester in 12 pregnant baboons, 7 not in labor and 5 in labor, and examined PGHS2 mRNA expression throughout the uterus. PGHS2 mRNA abundance was quantified by in situ hybridization and northern blot analysis in the uterine fundus, lower uterine segment and the different segments of the cervix. Quantitative northern blot and in situ analysis demonstrated a gradient of PGHS2 mRNA expression, with the highest levels at the level of the lower portion of the cervix and decreased expression through the mid- and upper portion of the cervix and lower uterine segment; the lowest levels of expression were seen in the uterine fundus. Moreover, cellular localization of PGHS2 mRNA and protein demonstrated high levels of expression in the cervical glandular epithelial cells with only occasional staining of smooth muscle cells in pregnant baboons. Decreased PGHS2 mRNA concentration gradient from the cervical external os to the fundus suggests that prostaglandin (PG) production in the uterus and cervix strongly depends on anatomical relations. This increased local PG production activity may be critical to pregnancy-associated lower uterine segment elongation, cervical softening and effacement in primate labor. These data provide a compelling biological basis for the use of PGHS2 inhibitors in the prophylaxis of preterm birth and cervical incompetence.

Effects of gestational age and labor on expression of prostanoid receptor genes in baboon uterus.

We determined the effect of gestational age and labor on the regional expression of prostanoid receptor genes in baboon myometrium. Cesarean hysterectomy was performed on 15 pregnant baboons of known gestational age in the last third of pregnancy, five of them during spontaneous term labor. Expression of prostanoid receptor genes was studied using Northern blot analysis. Transcripts of similar size to the human were detected for prostanoid EP(1), EP(2), EP(3), EP(4), IP, FP, and TP receptor genes using Northern blot analysis. There were no gestational age-related changes in expression of these genes. Expression of EP(1), EP(3), and IP receptor RNA mRNA was significantly higher in myometrium from the fundus (compared with the lower segment), whereas EP(2) gene expression was significantly lower in the fundus. Labor was associated with a reduction in the regional variation of both EP(2) and IP receptor gene expression, but not EP(1) and EP(3) expression. Labor was also associated with an overall lower level of expression of EP(2) receptor mRNA. We conclude that regional and labor-related variation in myometrial expression of prostanoid receptor genes may have a key role in primate parturition.

Modulation of the Action of Chorionic Gonadotropin in the Baboon (Papio anubis) Uterus by a Progesterone Receptor Antagonist (ZK 137.316)1

Signals from the developing mammalian blastocyst rescue the corpus luteum (CL) and modulate the uterine environment in preparation for implantation and early pregnancy. Our previous studies demonstrated that both short- and long-term administration of chorionic gonadotropin (CG) markedly alters the morphology and the biochemical activity of the receptive endometrium. Because the effects of CG were superimposed on a progesterone-primed endometrium, this study was undertaken to determine if the inhibition of progesterone action by progesterone receptor antagonists (PRa) in intact and ovariectomized baboons would alter the action of CG on the endometrium at the time of uterine receptivity. In the short-term hCG-treated baboons, the PRa reduced the epithelial plaque reaction, completely inhibited alpha-smooth muscle actin (alphaSMA) expression in stromal fibroblasts, and induced the reappearance of the progesterone (PR) and estrogen (ERalpha) receptors in epithelial cells. However, this treatment protocol had no effect on the expression of glycodelin in the glandular epithelium. In contrast, glycodelin expression in addition to alphaSMA was suppressed in the ovariectomized animals. In the long-term hCG-treated baboons, the PRa had a similar effect on both alphaSMA, PR, and ER. In addition, this treatment also resulted in an inhibition of glycodelin expression in the glandular epithelium. These results indicate that blocking the action of progesterone on the endometrium even for a short period of time has a profound effect on the hCG-induced response in stromal fibroblasts. In contrast, for the diminution of glandular epithelial function in the presence of an ovary requires prolonged inhibition of progesterone action, suggesting a potential paracrine effect on the endometrium from the CL in response to hCG.

Expression of Prolactin and Its Receptor in the Baboon Uterus during the Menstrual Cycle and Pregnancy1

PRL is known to be a major secretory product of the human decidua. However, the physiological role of decidual PRL during the menstrual cycle and pregnancy has not been fully defined, primarily due to the lack of an appropriate nonhuman primate model for in vivo studies. Therefore, this initial study examined the expression of PRL and its receptor in the baboon uterus during the cycle and pregnancy. PRL and PRL receptor messenger ribonucleic acid expression were detected by semiquantitative RT-PCR, and protein was localized by immunocytochemistry. PRL was shown to be expressed in myometrial smooth muscle during the follicular phase by both RT-PCR and immunocytochemistry. Expression of PRL messenger ribonucleic acid and protein was first observed in the epithelial cells of the deep basal glands during the late luteal phase. With the onset of pregnancy, PRL expression increased steadily and was evident primarily in the decidual tissue. In contrast to PRL, its receptor was expressed at constant levels in both the myometrium and endometrium during the cycle. An increase in receptor expression was evident in both the decidua and placenta throughout pregnancy. In summary, these results demonstrate that the baboon uterus is a site of both PRL production and action during the cycle and pregnancy. These studies establish the baboon as a nonhuman primate model to investigate the potential roles of PRL in implantation and maintenance of pregnancy.

Expression of Prolactin and Its Receptor in the Baboon Uterus during the Menstrual Cycle and Pregnancy

Expression of Prolactin and Its Receptor in the Baboon Uterus during the Menstrual Cycle and Pregnancy

Regional variations in contractile responses to prostaglandins and prostanoid receptor messenger ribonucleic acid in pregnant baboon uterus

Objectives: The aims of this study were to compare (1) the contractile responses of the lower uterine segment and fundus to prostaglandins, (2) expression of genes encoding prostanoid receptors in myo-metrium from different regions of the uterus, and (3) the distribution of expression of genes encoding prostanoid receptors (P receptors) in key intrauterine tissues. Study Design: Cesarean hysterectomy was performed in 8 pregnant baboons, not in labor, in the last third of pregnancy. Contractile responses of fresh tissue were quantified in a superfusion system. Polyadenylated ribonucleic acid was extracted from frozen tissue and gene expression was quantified by Northern blot analysis with complementary deoxyribonucleic acid probes. Results: Prostaglandin E 2 contracted strips of myometrium from the fundus but had no significant effect on strips from lower uterine segment. Prostaglandin F 2 α contracted myometrium from both regions equally. Compared with fundus tissue, lower uterine segment tissue had greater expression of EP 2 receptor messenger ribonucleic acid, less expression of EP 3 receptor messenger ribonucleic acid, but similar levels of EP 4 receptor and FP receptor messenger ribonucleic acid. EP 2 receptor, EP 3 receptor, and EP 4 receptor messenger ribonucleic acids were also detected in cervix, decidua, and chorion. EP 2 receptor messenger ribonucleic acid was most abundant in the cervix, EP 3 receptor messenger ribonucleic acid was most abundant in the myometrium, and EP 4 receptor messenger ribonucleic acid was most abundant in the decidua. Conclusions: The reduced contractile response of lower uterine segment tissue to prostaglandin E 2 is paralleled by greater inhibitory EP 2 receptor expression and less contractile EP 3 receptor expression, a pattern similar to that seen in the cervix. Drugs with selective activity at prostanoid receptor types and subtypes are likely to allow safer and more effective control of the uterus and cervix than native prostaglandins. (Am J Obstet Gynecol 1998;179:1545-52.)

Parathyroid hormone–related peptide (1 to 34) inhibits in vitro oxytocin-stimulated activity of pregnant baboon myometrium

OBJECTIVES: We sought to determine the in vitro effect of parathyroid hormone–related protein fragment 1 to 34 on oxytocin precontracted myometrium from baboons in late gestation and to explore possible regional uterine differences in responsiveness comparing muscle strips from the lower uterine segment, posterior and anterior corpus, and fundus. STUDY DESIGN: We used cumulative concentration response (1 to 100 nmol/L) curves to parathyroid hormone–related protein (1 to 34) in isolated strips of baboon myometrium obtained at cesarean hysterectomy of 6 pregnant baboons in the last third of pregnancy. RESULTS: Parathyroid hormone–related protein (100 nmol/L) decreased both amplitude and frequency of contraction. The maximum effect of parathyroid hormone–related protein on the amplitude of contractions was greater than saline solution (2-way analysis of variance, F ratio 424.0, P < .001), but there was no difference comparing the four regions of the uterus ( F ratio 1.342, P = .286). The maximum effect of parathyroid hormone–related protein on the frequency of contractions was greater than saline solution (2-way analysis of variance, F ratio 162.5, P < .0001), but no difference in response was noted in the 4 regions of the uterus ( F ratio = 0.682, P = .572). CONCLUSION: Parathyroid hormone–related protein completely inhibited the contractile effect of high doses of oxytocin in the lower segment, corpus, and fundus of the baboon uterus. No difference in response of myometrium was obtained from different regions of the uterus. (Am J Obstet Gynecol 1998;179:492-6.)

Regulation of the glycosylated beta-lactoglobulin homolog, glycodelin [placental protein 14:(PP14)] in the baboon (Papio anubis) uterus.

In vitro studies indicate that glycodelin (PP14) synthesis by the human endometrium increases dramatically at the time of implantation and early pregnancy. It has been postulated that this protein may have an immunosuppressive function. Due to the limitations associated with in vivo studies in the human, this study was undertaken to study the regulation of the baboon glycodelin homolog in vivo during the menstrual cycle and early pregnancy. In nonpregnant baboons, between days 10-12 postovulation (n = 3) the mid and apical regions of the glandular epithelium showed a distinct punctate staining pattern, which increased between days 12-18 of pregnancy (n = 3). Between days 25-60 of pregnancy, staining intensity in the glandular epithelium decreased. The decrease was more apparent at the implantation site compared with the nonimplantation site. The immunostaining correlated with the synthesis of radiolabeled baboon glycodelin in explant culture. Northern blot analysis demonstrated two messenger RNA (mRNA) transcripts [1.0 and 1.7 kilobases (kb)] in the baboon uterus compared with a single 1.0-kb transcript in the human, and mRNA expression was consistent with protein localization and synthesis. The protein and mRNA expression was consistently higher in the deeper glands of the functionalis and basalis during early pregnancy. Because the increased expression of glycodelin in the baboon endometrium coincided with peak levels of CG, a simulated pregnant baboon model was used to confirm hormonal regulation. Exogenous human CG (hCG) followed by estrogen and progesterone treatment in intact and ovariectomized baboons up-regulated glycodelin expression between days 18-25 postovulation (n = 10). By day 32 postovulation (n = 3), glycodelin synthesis decreased. Estrogen and progesterone treatment in the absence of exogenous hCG did not result in an increase of glycodelin synthesis. Analysis of uterine flushings from hCG-treated animals revealed that a minimum of 7 days of hCG treatment was required for glycodelin to be detectable in the uterine lumen. These studies indicate that a posttranslationally modified glycodelin homolog is synthesized by the baboon uterus during early pregnancy and appears to be regulated directly by CG. This pattern of synthesis is comparable with that observed with in vitro studies in the human. Because glycodelin expression is associated with CG secretion, we suggest that this protein may have a functional role during implantation in the primate. Thus, the baboon may serve as a nonhuman primate model to elucidate the function of this protein in vivo.

Regulation of cyclins E and D, and the p2l inhibitor in the baboon uterus during the menstrual cycle and the window of uterine receptivity

Regulation of cyclins E and D, and the p2l inhibitor in the baboon uterus during the menstrual cycle and the window of uterine receptivity

Smooth Muscle Myosin II and Alpha Smooth Muscle Actin Expression in the Baboon (Papio Anubis) Uterus is Associated with Glandular Secretory Activity and Stromal Cell Transformation1

The objective of this study was to investigate the localization and hormonal regulation of smooth muscle myosin II (SMM II) and alpha smooth muscle actin (alpha SMA) in the baboon uterus, since cytoskeletal proteins are involved in secretory function and morphological transformation. Uterine tissue was obtained from baboons 1) during the menstrual cycle, 2) following steroid treatment of ovariectomized baboons, 3) during pregnancy (Days 14-60 postovulation [PO]), and 4) during simulated pregnancy (Days 18-32 PO). Tissues were processed for immunocytochemical localization of SMM II or alpha SMA with specific polyclonal or monoclonal antibodies, respectively. SMM II stained all smooth muscle cells of blood vessels and myometrium regardless of treatment. Glandular epithelial staining was present only in endometrium obtained during the luteal phase or following estrogen and progesterone treatment. Staining intensity was greater in the basalis than in the functionalis. The number of glands staining positive for SMM II on Days 18-32 of pregnancy and simulated pregnancy was variable. Glandular stain was absent after Day 32 PO. These immunocytochemical data were confirmed by immunoblot analysis of glandular cytosolic extracts. Stromal staining for SMM II was present under the luminal epithelium during simulated pregnancy (Days 18-32), on Day 25 of steroid treatment in the simulated-pregnant controls, and in nonimplantation sites during pregnancy. In contrast, alpha SMA staining was low or absent in all uterine cell types in ovariectomized baboons. Under estrogen-dominated conditions (follicular phase and estrogen treatment), alpha SMA staining was present in smooth muscle cells, and this staining persisted throughout the remaining treatment periods. Glandular epithelial staining for alpha SMA was absent in all treatment groups. However, alpha SMA staining in stromal fibroblasts underneath the luminal epithelium was evident as early as Day 14 of pregnancy and Day 18 of simulated pregnancy. The number of stromal fibroblasts that stained positive increased in the surface region of the functionalis between Days 18 and 32 PO, and the staining extended throughout the upper functionalis region. There was a decrease in the number of positively stained stromal fibroblasts, particularly at the implantation site, between Days 32 and 40 of pregnancy. By Days 50-60 of pregnancy, this staining was almost absent. The induction of alpha SMA in stromal fibroblasts in the functionalis region in pregnant baboons was confirmed by immunoblot analysis of stromal cell cytosol extracts. We conclude that the progesterone-induced glandular expression of SMM II may be involved in uterine secretory function and that alpha SMA expression in stromal fibroblasts during pregnancy and after long-term steroid treatment is associated with the decidualization process.

Secretory proteins and growth factors of the baboon (Papio anubis) uterus: potential roles in pregnancy.

The primate endometrium undergoes distinct morphological changes during the menstrual cycle. These alterations are regulated by the steroid hormones, estrogen and progesterone. Several lines of evidence suggest that some of these hormonally induced changes may be modulated by growth factors. Our studies have focused on characterizing the secretory activity of the uterine endometrium associated with these hormonally regulated morphological changes during the menstrual cycle and pregnancy in the baboon. Additionally, we have also attempted to study the regulation of specific growth factors and their receptors. In this review we present evidence to indicate that growth factor receptors for insulin-like growth factor-I (IGF-I) and epidermal growth factor (EGF), and secretory proteins, insulin-like growth factor binding protein-1 (IGFBP-1) and retinol binding protein (RBP), which are present in the glandular epithelium during the menstrual cycle, undergo cell-specific changes in gene expression at the implantation site during pregnancy. We postulate that these alterations in growth factor receptor and secretory protein expression are conceptus modulated and may play important regulatory roles during trophoblast invasion and decidualization.

Oxytocin antagonist inhibitory effect on the rat and baboon uterus may be overcome by prostaglandins

A potent, long-acting oxytocin antagonist produced in our laboratory (ANTAG-III) can inhibit uterine response to oxytocin in the rat and baboon for hours and even days. The purpose of this study was to evaluate uterine response to prostaglandins subsequent to the administration of ANTAG-III. For the rat study one cannula was inserted in the jugular vein, and another cannula to measure uterine activity was inserted in the uterus. In study 1 saline solution or 5 micrograms of ANTAG-III was administered to five rats each, followed by 100 mU of oxytocin at 0.1, 1, and 2 hours. In study 2 six rats each were infused with saline solution of 5 micrograms of ANTAG-III, followed 1 hour later by 5 micrograms of 15-methyl-prostaglandin F2 alpha and uterine activity monitored. After baseline activity returned to normal 100 mU of oxytocin was infused and the uterine response reassessed. For the baboon study ANTAG-III was administered into the aorta of tethered pregnant baboons (n = 2). An oxytocin challenge test was performed starting with 10 mU/min and going up to 400 mU/min. After a significant uterine contractile response was established and activity returned to baseline, a 15-methyl-prostaglandin F2 alpha challenge test was performed. During the period in which the response to oxytocin was inhibited the uterine response to 15-methyl-prostaglandin F2 alpha of the estrous rat and pregnant baboon was maintained. The inhibition of the estrous rat and pregnant baboon uterus to oxytocin caused by ANTAG-III may be prolonged. During this period uterine response to prostaglandins is not altered.

Retinol-Binding Protein in the Baboon (Papio Anubis) Uterus: Immunohistochemical Characterization and Gene Expression1

Retinols and retinoic acid (vitamin A) are essential for embryonic development; they are transported in circulation bound to retinol-binding protein (RBP). RBP has been shown to be synthesized in extrahepatic sites, i.e., the progestational uterus and concepti of pig, sheep, and cows. This study was undertaken to determine whether RBP is also synthesized by the primate reproductive tract. Uterine tissues were obtained from mature female baboons during the follicular and luteal stages of the menstrual cycle, after steroid (estrogen +/- progesterone) treatment of ovariectomized baboons and between Days 18 and 32 of pregnancy. Portions of the uterine tissues were either fixed in Bouin's fixative and embedded in paraffin, subjected to explant culture, or immediately frozen in liquid nitrogen for RNA isolation. Our studies indicate that RBP is present in the uterine glandular epithelium of the baboon during the late luteal stages of the menstrual cycle. Steroid hormone treatment of ovariectomized female baboons confirmed that both transcription and translation of uterine RBP is under progestational control. When uterine and placental tissues from pregnant baboons were analyzed between Days 18 and 32 of pregnancy, it was apparent that immunoreactive RBP increased in the mid and basal glands initially, but by Day 32 all of the glands stained positively. In contrast, the mRNA levels peaked at Day 25, and RBP message was more highly expressed in the basalis region of the uterus compared to the functionalis. Immunoreactivity for RBP was higher at the implantation site compared to the nonimplantation site. Neither RBP protein nor message was detectable in the baboon conceptus/placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization, localization, and regulation of receptors for insulin-like growth factor I in the baboon uterus during the cycle and pregnancy.

The objective of this study was to determine the presence, regulation, and localization of specific receptors for insulin-like growth factor I (IGF-I) in primate reproductive tissues. Uteri were obtained from baboons either during the menstrual cycle, after ovariectomy with or without steroid treatments, or during early pregnancy (Days 18-60 postovulation [PO]). Placental and decidual tissues were collected from baboons during late pregnancy (Days 130-160). Localization of type I IGF receptor was determined by indirect immunocytochemistry (alpha IR3 antibody), and levels of type I IGF receptors were determined by affinity cross-linking and binding assays. Specific staining for type I IGF receptors was present in the membranes of glandular epithelial cells throughout the cycle and early pregnancy; however, there was a decrease in staining intensity by the late luteal phase and also throughout early pregnancy compared to the late follicular phase. Specific receptor staining was absent in stromal cells throughout the cycle. By Day 19 PO, stromal cells directly under the trophoblast were positive for type I IGF receptor, and an increase in stromal staining at the implantation site was observed as pregnancy proceeded. Stromal staining was apparent in non-implantation site tissue by Day 32 PO. Some placental villi showed positive receptor staining as early as on Day 18 PO, and an increase in the number of positive villi was apparent as pregnancy progressed. An 125I-IGF-I-protein complex of approximately 140,000 daltons, corresponding to the alpha subunit of the type I IGF receptor, was detected in endometrial, placental, and decidual membranes. The intensity of this signal was high in endometrium from the follicular phase, whereas low levels were detected in endometrium from the luteal phase. Throughout early pregnancy, alpha receptor subunit was present in placental and decidual membranes; alpha receptor subunit increased in placenta as pregnancy proceeded. An additional 125I-IGF-I-protein complex of 43,000 daltons, corresponding to IGF binding protein-1 (IGFBP-1), was present in decidual membranes and appeared to increase as pregnancy proceeded. Specific binding of 125I-IGF-I to placental membranes was displaced by unlabeled IGF-I and alpha IR3 antibody, whereas both unlabeled IGF-I and IGF-II competed equally for binding to decidual membranes. Scatchard analysis of 125I-IGF-I binding to placental membranes revealed a single class of high-affinity receptors (KD = 2.35 +/- 0.8 nM; mean +/- SEM).(ABSTRACT TRUNCATED AT 400 WORDS)

Secretory and Morphological Changes in the Baboon (Papio Anubis) Uterus and Placenta during Early Pregnancy1

The study was undertaken to characterize changes in uterine endometrial secretory activity and morphology in the baboon between Days 18 and 32 of pregnancy. Proteins synthesized by the implantation site endometrium (RI) and non-implantation site endometrium (RIII) and developing placenta were analyzed by two-dimensional PAGE and fluorography. The electrophoretic mobility and localization of chorionic gonadotropin (CG) in the baboon placenta, and insulin-like growth factor binding protein-1 (IGFBP-1) and retinol binding protein (RBP) in the baboon uterus were confirmed by Western blot analysis and immunocytochemistry. Placental protein synthesis was primarily characterized by the presence of radiolabeled CG at Days 18 and 25, which decreased by Day 32. Peak CG synthetic activity, immunolocalized to the syncytiotrophoblast, occurred during the formation of tertiary villi. Also associated with the development of mature villi was a corresponding increase in a basic protein (M(r) 23,000). The overall secretory pattern of the baboon endometrium was similar to that observed during the midluteal stage; however, the synthetic activity was enhanced during pregnancy. Radiolabeled and immunoreactive IGFBP-1 and RBP were detectable in the Day 32 functionalis and basalis, respectively, and their synthesis was higher in RI compared to RIII. The immunolocalization of IGFBP-1 in RI appeared to be directly related to the degree of decidualization. In addition, a novel group of low molecular-weight (M(r) 27,000-30,000) isoelectrovariant proteins was secreted predominantly by the basalis at Days 18 and 25 of pregnancy and disappeared by Day 32 in all but one animal. The synthesis of this group of proteins did not show regional specificity. These studies indicate that the baboon endometrium undergoes morphological and secretory changes during pregnancy that are associated with the development of a functional placenta and decidualized endometrium. Furthermore, these studies suggest that the conceptus/placenta may mediate specific changes in IGFBP-1 and RBP expression at the implantation site.