Observations on the vasculature of the reproductive tract in some Australian marsupials

The origin, distribution and structure of the blood vessels of the female reproductive tract and the testis of the brush possum (Trichosurus vulpecula) were studied using latex and silicone rubber casting and histological techniques. Latex casts of the vessels of the female tract were also studied in five macropod species – Macropus giganteus, M. eugenii, M. agilis, Megaleia rufa and Thylogale billardierii, and in the common wombat (Vombatus ursinus). The female reproductive tract in the brush possum was supplied and drained by four major sets of paired vessels – ovarian, cranial urogenital, caudal urogenital, and internal pudendal arteries and veins. These vessels formed substantial anastomoses with one another on each side of the midline, and also across-the-midline anastomoses. The proximal part of the ovarian artery ran in close apposition to the ovarian vein, which received one or more large uterine branches. In its distal protion the ovarian artery gave rise to a leash of small, tortuous ovarian branches, which wound around and between the plexiform ovarian veins. The testicular arteries and veins in this species also ran in close apposition to one another. Both arteries and veins branched into many smaller, mildly tortuous, parallel vessels in the spermatic cord, which reunited before entering the testis. The blood vessels of the reproductive tract in all of the macropod species studied, and in the common wombat, were basically similar to those of the brush possum. The intimate structural relationships between ovarian arteries and veins, and their ovarian branches, in these marsupials are suggestive of specializations for counter-current exchange between venous and arterial blood. However, in contrast to those of the testicular vessels where heat exchange is a demonstrated function, their physiological significance remains unknown.     

Branchial vascular pathways in two species of Tetraodontiformes and the concept of secondary vessels and nutrient arteries

The vascular organisation of the branchial basket was examined in two Tetraodontiform fishes; the three-barred porcupinefish, Dicotylichthys punctulatus and the banded toadfish, Marylina pleurosticta by scanning electron microscopy of vascular casts and standard histological approaches. In D. punctulatus, interarterial anastomoses (iaas) originated at high densities from the efferent filamental and branchial arteries, subsequently re-anastomosing to form progressively larger secondary vessels. Small branches of this system entered the filament body, where it was interspersed between the intrafilamental vessels. Large-bore secondary vessels ran parallel with the efferent branchial arteries, and were found to constitute an additional arterio–arterial pathway, in that these vessels exited the branchial basket in company with the mandibular, the carotid and the afferent and efferent branchial arteries, from where they gave rise to capillary beds after exit. Secondary vessels were not found to supply filament muscle; rather these tissues were supplied by single specialised vessels running in parallel between the efferent and afferent branchial arteries in both species examined. Although the branchial vascular anatomy was generally fairly similar for the two species examined, iaas were not found to originate from any branchial component in the banded toadfish, M. pleurosticta, which instead showed a moderate frequency of iaas on other vessels in the cephalic region. It is proposed that four independent vascular pathways may be present within the teleostean gill filament, the conventional arterio–arterial pathway across the respiratory lamellae; an arterio–arterial system of secondary vessels supplying the filament and non-branchial tissues; a system of vessels supplying the filament musculature; and the intrafilamental vessels (central venous sinus). The present study demonstrates that phylogenetic differences in the arrangement of the branchial vascular system occur between species of the same taxon.     

环颈雉胃的血供

用血管铸型法和大体解剖学方法对环颈雉胃动脉的起源、分布及胃静脉的回流情况进行了解剖学研究。结果表明,环颈雉的胃动脉均由腹腔动脉分出;腺胃由腺胃背侧动脉和腺胃腹侧动脉营养,腺胃背侧动脉直接起自腹腔动态的左侧,腺胃腹侧动脉起自腹腔动脉左支。腺胃血液的静脉有腺胃前静脉和腺胃后静脉,分别汇入后腔静脉和左肝门静脉。肌胃由肌胃左动脉、肌胃右动脉和肌胃背侧动脉营养,肌胃左动脉起自腹腔动脉的左支;肌胃右动脉起自腹腔动脉的右支;肌胃背侧动脉从腺胃背动脉分支而来。回流肌胃血液的静脉有胃右静脉、胃左静脉和胃腹侧静脉;胃右静脉汇入右肝门静脉,胃左静脉和胃腹侧静脉汇入左肝门静脉。另外腺胃和肌胃的表面缺乏主干动脉间的吻合。     

The arterial supply of the cervical vertebral body in newborns

The cervical vertebral column is mainly supplied by both vertebral arteries. A regular ladder pattern of arteries is on the dorsal plane as well as on the ventral plane of the cervical vertebral bodies, opposite to the thoracal and the lumbar area of the vertebral column with only a dorsal ladder pattern of arteries. The cervical arterial anastomoses are built by the segmental arteries of the vertebral arteries, in the back of the cervical vertebral bodies by the arteriae canalis vertebralis anteriores and in the front by the rami anteriores (corporum vertebrarum). The thyrocervical and the costocervical trunks are an additional blood supply especially to the ventral anastomoses. A loss of a segmental artery may have no effect because of the good anastomoses. Some decades of aa. nutriciae come in the vertebral body from all sides, but only 2 up to 4 rr. centrales anteriores and 2 rr. centrales posteriores join in the middle of the vertebral body. There are parallels to the arterial blood supply of the thoracal and the lumbar vertebral bodies. The longitudinal ligaments are supplied by both ladder patterns of arteries.     

Vascular anatomy of the gills of the stingarees Urolophus mucosus and U. paucimaculatus (Urolophidae,Elasmobranchii)

The branchial vascular anatomy of Urolophus mucosus and U. paucimaculatus was studied by scanning electron microscopical examination of critical-point-dried tissue or of vascular corrosion casts. The vasculature could be divided into arterioarterial and arteriovenous pathways, which channel the flow of blood through the gills. The arterioarterial pathway consists of an afferent branchial artery which gives rise to afferent distributing arteries that run through the tissues of the interbranchial septum and supply the afferent filament arteries of several filaments. Afferent filament arteries open regularly into a corpus cavernosum in the core of the filament; unlike other elasmobranchs no septal corpora cavernosa are found. At the tip of the filament, channels of the corpus cavernosum connect to a channel which passes across the distal end of the filament from afferent to efferent side. This channel always connects to the afferent filament artery, and in many filaments it connects to the efferent filament artery as well. In addition, a vascular arcade connects all the afferent filament arteries along the entire length of each hemibranch. The filament corpus cavernosum supplies the secondary lamellae. The lamellae drain into efferent lamellar arterioles which in turn drain into the efferent filament artery and the efferent branchial artery. The vascular anatomy of the arteriovenous pathway is similar to that described in other elasmobranchs and consists of arteriovenous anastomoses, found only arising from efferent arterial circulation, and the venolymphatic system, which is composed of the central venous sinus and the companion vessels.     

Scanning electron microscopy of vascular architecture in the gastric mucosa of the golden hamster

Summary The three-dimensional architectures and the regional differences of the vascular system in the mucosa of the hamster stomach were revealed by scanning electron microscopy of corrosion casts. In the forestomach, the vascular network spreads two-dimensionally in a thin lamina propria. In the corpus and the antrum, the capillaries in the thick lamina propria are well developed, extending three-dimensionally along the gastric pits and glands. In the corpus, the submucosal arteries enter the lamina propria to become ascending capillaries, which project toward the top of the lamina propria and anastomose to create a capillary network beneath the mucosal epithelium. A subepithelial capillary is much wider in diameter than an ascending capillary and is, therefore, a sinusoid capillary. Subepithelial capillaries join descending venules, which are less numerous than the ascending capillaries. Near the gastric lumen, the capillaries in the corpus can be classified into two types: arched type in the cephalic (upper) region and honeycomb type in the caudal (lower) region. In the antrum, the submucosal arterial plexus is less well developed than that in the corpus. The mucosal aspect of the corrosion cast shows many clumps, formed by a unit of capillary network. Functional significances of different vascular architectures in the gastric mucosa of the forestomach, corpus, and antrum are discussed.This study was supported in part by grants from the Research Fund of the Ministry of Education, Science, and Culture, Japan     

Stabilizing rôle of epididymal plasma in relation to the capacitation time of boar spermatozoa

Functional aspects of the maturation of epididymal spermatozoa have been examined by means of surgical insemination of two types of sperm suspension directly into the oviducts. Suspensions were prepared by macerating tissue from the upper corpus region of the epididymis, and cell-free plasma was prepared from the contents of the cauda epididymidis. Each comparison of the fertilizing ability of the two sperm suspensions was made within the same animal, known numbers of upper corpus spermatozoa in either medium TCM 199 or caudal plasma being instilled into separate oviducts close to the time of ovulation.Activated eggs were recovered from 11 of 12 inseminated animals some 4–6 h later, but within the intervals examined there was a distinct difference in the fertilizing ability of the two types of sperm suspension; 87% of the eggs were activated by upper corpus spermatozoa in TCM 199 compared with 9% of the eggs exposed to similar spermatozoa suspended in caudal plasma. Furthermore, the fertilization process was invariably more advanced when eggs had been activated by the upper corpus spermatozoa suspended in TCM 199, and the number of spermatozoa on or in the zona pellucida was likewise consistently higher with such sperm suspensions. The rôle of the factor(s) in cauda epididymal plasma contributing to the observed delay in fertilizing ability is discussed in the context of sperm transport and capacitation after natural mating.     

Three-dimensional analysis of the arterial pattern of the upper limbs in Lorisiformes (Prosimiae, Primates)

A study of the arterial patterns of the upper limbs in Lorisiformes (Prosimiae), especially those of the rete mirabile and their correlating arteries, was carried out by three-dimensional arteriographic analysis. The rete displayed at least two types of plexiform distribution: (1) a vascular bundle in Lorisidae, which consists of a division of the main artery into a principal trunk surrounded upwards by about 50 small arteries, and (2) a simple network pattern in Galagidae, which, at most, is composed of simple vascular networks of the nature of a few widely scattered anastomoses. The arterial patterns of the upper limb in Lorisiformes are basically the same, but the position of divergence and the number and size of the vessels in the rete differ. The arterial patterns of the upper limbs in Lorisiformes closely resemble the development of the vessels in the 21- to 23-mm stages of human embryonic growth. In this study, we observed some similarity in the patterns between the rete mirabile and the superficial brachial artery in man.     

The angioarchitecture of estrous, pseudopregnant and pregnant rabbit ovary as seen by scanning electron microscopy of vascular corrosion casts

Ovarian angioarchitecture was studied by scanning electron microscopy of vascular corrosion casts in estrous, pseudopregnant (stimulated with human chorionic gonadotropin) and pregnant rabbits. In all samples, the proper ovarian branch of the ovarian artery (ramus ovaricus) entered the ovarian hilus near the caudal pole of the organ and ran parallel to the major axis of the hilus. The extraovarian venous drainage was formed by several vessels emptying into a distal large vein. The ramus ovaricus exhibited various degrees of coiling and branched in the medulla. The coiling of the ramus ovaricus and its ramifications were maintained in all samples. A venous meshwork and/or flat vein branches closely enveloped the arterial coils found in the hilus and outer medulla. At this level numerous arteriovenous contacts were demonstrated in all samples. The coiled arteries, prior to entering the ovarian cortex, supplied several small peripheral follicles which were drained by the hilar veins. In the cortex the coiled arteries branched in numerous thin, straight or slightly undulated arterioles which supplied developing estrous follicles and pseudopregnant corpora lutea. The arterioles supplying the pregnant corpora lutea were long, large and tightly spiraled. The venous drainage followed the modifications of the arterial supply. These data demonstrate that ovarian cycle and pregnancy induced significant changes in the cortical vessels, which adapted their structure to the temporary functional needs of the recruited follicles or corpora lutea. Hilar and medullary vessels have permanent structures that may represent morphological devices for (a) a continuous control of the blood flow (spiral arteries) and (b) a local recirculation of endocrine products (arteriovenous contacts) comparable to the ”countercurrent mechanism” previously shown to operate in ovaries of other species, but not yet found in rabbits. Received: 19 June 1996 / Accepted: 7 October 1996     

Expression of urocortin and its receptors in the rat epididymis

Urocortin (UCN; 40 aa) is a corticotrophin-releasing hormone (CRH)-related peptide. The biological actions of CRH family peptides are mediated by two types of G-protein-coupled receptors, CRH type 1 receptor (CRHR1) and CRH type 2 receptor (CRHR2). The biological effects of the peptides are mediated and modulated not only by CRH receptors but also by a highly conserved CRH-binding protein (CRHBP). The aim of the present study was to investigate the expression of UCN, CRHR1, CRHR2 and CRHBP by immunohistochemistry, Western blot, RT-PCR and real-time RT-PCR in the rat epididymis. Urocortin, CRHR1 and CRHR2, but not CRHBP, were expressed in all segments of the rat epididymis. Specifically, UCN- and CRHR2-immunoreactivities (IRs) were distributed in epididymal epithelial cells of the caput, corpus and cauda. CRHR1-IR was found in the fibromuscular cells surrounding the epididymal duct and in the smooth musculature of the blood vessels throughout the organ. UCN and CRHR2 mRNA expression levels were higher in the caput and corpus than in the cauda, while CRHR1 mRNA level was higher in the cauda than those in the caput and corpus. In summary, UCN, CRHR1 and CRHR2 are expressed in the rat epididymis. It is suggested that CRH-related peptides might play multiple roles in the maturation and storage of spermatozoa.     

Isolation, immunolocalization, and sperm-association of three proteins of 18, 25, and 29 kilodaltons secreted by the mouse epididymis.

Three murine epididymal secretory proteins have been characterized by their site of synthesis, sperm association, and tissue localization by use of polyclonal antisera and immunochemistry. Mouse epididymal protein 7 (MEP 7) was localized initially within the supranuclear regions of some principal epithelial cells in the proximal corpus while other cells remained unstained. In the mid-proximal corpus, all principal cells and stereocilia were stained, and luminal staining increased from corpus to cauda. Some clear cells in the distal corpus and cauda also showed immunoperoxidase staining. Sequential extraction of caudal spermatozoa indicated that MEP 7 was predominantly loosely associated with spermatozoa and that only a small amount of MEP 7 required detergent to extract it from spermatozoa. Examination of other rodent caudal fluids revealed a related protein in rat caudal fluid of 32 kDa, and amino acid sequence analysis of MEP 7 showed a 68% sequence similarity with rat proteins AEG and D/E. MEP 9 immunolocalized within the cytoplasm of all principal cells of the distal caput. In a transition zone between the distal caput and the corpus, some principal cells were stained while others were not. Distal to the corpus, the principal cell staining gradually decreased. In the distal caput and proximal corpus, large heavily stained droplets associated with spermatozoa were seen in the lumen. The staining intensity of these droplets also decreased from corpus to cauda. The clear cells of the distal corpus and cauda did not stain with the antibody to MEP 9. Sequential extraction of caudal spermatozoa showed that some MEP 9 was extractable under low-salt conditions, whereas extraction with 0.1% Triton X-100 was required to remove all MEP 9, indicating it was firmly associated with spermatozoa. The antibody to MEP 9 cross-reacted with a 25-kDa protein present in rat caudal fluid. MEP 10 was localized within the cytoplasm of the principal cells, the stereocilia, and the lumen of the epididymis at the junction of the distal caput and corpus. In the distal corpus, a large number of clear cells were stained, but very few of these cells stained in the cauda. MEP 10 dissociated completely from caudal spermatozoa under low-salt conditions, indicating that it was not firmly bound to spermatozoa. The antiserum to MEP 10 cross-reacted with proteins present in rat and guinea pig caudal fluid. The related rat protein migrated at approximately 20 kDa. Amino acid sequence analysis of MEP 10 revealed an 86% sequence similarity with rat proteins B and C.(ABSTRACT TRUNCATED AT 400 WORDS)     

Urogenital vasculature and local steroid concentrations in the uterine branch of the ovarian vein of the female tammar wallaby (Macropus eugenii)

The urogenital vasculature of the tammar comprises 4 major paired arteries and veins: the ovarian, the cranial urogenital, the caudal urogenital and the internal pudendal artery and vein. The ovarian artery and vein and their uterine branches which supply the ovary, oviduct and uterus, ramify extensively. Each anterior urogenital artery and vein supplies the caudal regions of the ipsilateral uterus, lateral and median vagina and cranial parts of the urogenital sinus. The caudal urogenital arteries and veins supply the urogenital sinus and caudal regions of the bladder. The internal pudendal artery and vein vascularize the cloacal region, with some anastomoses with branches of the external pudendal vessels. Anastomoses connect the uterine branch of the ovarian artery with the uterine branch of the cranial urogenital and cranial branches of the caudal urogenital arteries, and connect the caudal urogenital and the internal pudendal arteries. Anastomotic connections between the left and right arterial supply also occur across the midline of the cervical regions of the uteri and the anterior lateral vaginae. Similar connections are seen in the venous system. The uterine branch of the ovarian artery ramifies extensively very close to the ovary, giving a plexiform arrangement with the ovarian veins, and also with the uterine venous system on the lateral side of each uterus. This plexiform structure provides an anatomical arrangement which could allow a local transfer of ovarian hormones from ovarian vein into the uterine arterial supply, and thence to the ipsilateral uterus. Progesterone concentrations in plasma from the mesometrial side of the uterine branch of the ovarian vein are markedly higher than in tail vein plasma, especially during the 'Day 5 peak' early in pregnancy, and also at full term. There is also a marked decrease in progesterone concentration from all sites immediately before birth as previously reported for peripheral plasma. These results support the suggestion of a countercurrent transfer mechanism, at least for progesterone, and possibly other hormones, between the ovarian vein and uterine artery. Such a local transfer could explain the different morphological responses of the endometria of the two adjacent uteri during pregnancy in macropodid marsupial species.     

Embryonic development of the ciliary arteries of the rabbit from inception through the emergence of the circulus arteriosus irdis

Since the rabbit's eye more nearly resembles the human eye than any other mammal used in experimental investigations, a detailed study of its ciliary arteries has been made. A closely timed series of embryos injected through the living umbilical vein and rendered transparent show, in thick sections, silhouetted vessels in perspective. Heretofore the ciliary arteries have been studied from their first identification until they have reached the primitive choriocapillaris, but no farther. This study shows their complete history including their relation to the circulus arteriosus iridis major and to the pupillary membrane. Our special concern has been ferreting out the mode of migration of the components of the definitive arteries. New findings include: (1) an arteriovenous plexus which mediates the transference from vessels anastomotic with it to other such vessels; (2) functionally different segments of the primitive ciliary arteries; (3) different arterial and venous plexuses which play roles in embryonic development; (4) discovery of the realignment of the choriocapillaris into vertical vessel meshes with transverse anastomoses between them, each of which have different fates; (5) the mode of development of the circulus arteriosus iridis major; (6) a crown of venous vessels looping around the iris margin; and (7) a special arterial supply for the ciliary processes.     

Contribution of the vertebral artery to cerebral circulation in the rat snake Elaphe obsoleta

Blood supplying the brain in vertebrates is carried primarily by the carotid vasculature. In most mammals, cerebral blood flow is supplemented by the vertebral arteries, which anastomose with the carotids at the base of the brain. In other tetrapods, cerebral blood is generally believed to be supplied exclusively by the carotid vasculature, and the vertebral arteries are usually described as disappearing into the dorsal musculature between the heart and head. There have been several reports of a vertebral artery connection with the cephalic vasculature in snakes. We measured regional blood flows using fluorescently labeled microspheres and demonstrated that the vertebral artery contributes a small but significant fraction of cerebral blood flow (∼13% of total) in the rat snake Elaphe obsoleta. Vascular casts of the anterior vessels revealed that the vertebral artery connection is indirect, through multiple anastomoses with the inferior spinal artery, which connects with the carotid vasculature near the base of the skull. Using digital subtraction angiography, fluoroscopy, and direct observations of flow in isolated vessels, we confirmed that blood in the inferior spinal artery flows craniad from a point anterior to the vertebral artery connections. Such collateral blood supply could potentially contribute to the maintenance of cerebral circulation during circumstances when craniad blood flow is compromised, e.g., during the gravitational stress of climbing. J. Morphol. 238:39–51, 1998. © 1998 Wiley-Liss, Inc.     

The rete mirabile cranica in the genus Mobula: A comparative study

Devil rays (Mobulidae) have large brains that rest in a voluminous chondrocranium almost completely filled by a rete mirabile cranica (RMC). The RMC is a massive arterial network grossly divisible into a “caudal RMC” supplying blood to the brain, and an expanded, more complex “precerebral RMC” nested within the large cranial cavity rostral to the telencephalon. Both the caudal and precerebral retia originate from the posterior portion of the profundae cerebri arteries, which lie ventral to the brain and form the sides of a vascular triangle, the base of which is anterior and formed by the joining of the internal carotids; the vertex is posterior and median, corresponding to the anterior extreme of the spinalis impar artery. Vessels of the caudal RMC branch posteriorly from the profundae cerebri and course over and into the brain. Vessels branching more anteriorly course rostrally to form the precerebral RMC, which takes the shape of the cranial cavity and completely envelops the olfactory peduncles. Large retial arteries (1-mm diameter) branch and taper to about 50–150 μm, forming a system of small arteries or arterioles. Many give rise to a mesh of tertiary vessels (precapillary arterioles or capillaries, ca. 20–50 μm in diameter), which, along with arterioles, are embedded in the adventitia of these arteries, with which they communicate by numerous anastomoses. Although the function of the RMC remains enigmatic, its complexity and fine structure are suggestive, and hypotheses of its role are discussed.     

Arterial blood supply to the laryngeal part of the pharynx]

The sources, anastomoses and variations of bloodsupply of the laryngeal part of the pharynx were studied in 100 corpses of different sex and age. It has been established that the fronto-lateral divisions of the laryngeal part of the pharynx are supplied with blood by pharyngeal branches of the superior and inferior paryngeal arteries. Ligation of the pharyngeal arteries during laryngectomy prior to their entering the larynx, i. e. before the divergence of the pharyngeal branches from them, as conventional, causes restriction of supply of these parts and can contribute to disjunction of the pharyngeal suture. The trunks of laryngeal arteries with their pharyngeal branches should be preserved, if possible. The posterior wall of the laryngeal part of the pharynx is divided into three zones depending on the main arterial sources (the ascending pharyngeal, superior and inferior thyroid arteries).     

Status of the "dead point" of blood flow in anastomoses of superficial cerebral arteries as affected by an acute increase of blood pressure

Changes in pial arteries diameter and the condition of blood flow "dead point" in arterial anastomoses were established using the brain window during an acute increase of mean arterial pressure (MAP) induced by intravenous injection of norepinephrine (NE) with microcineangiography and the analysis of films and frames on a montage table and TAS ("Leitz"). During an acute increase of MAP the movement of blood flow "dead point" in anastomoses and the expansion of plasma segments occurred much more frequently than in normotension. The stabilization of blood flow "dead point" was observed at high constant MAP. Pronounced dilation of both pial arteries and veins first occurred in anastomoses, then spread to arterial branches. It is assumed that high vulnerability of the brain vessels of the borderline zones is due to breakthrough in autoregulation of cerebral blood flow on its upper limit and depends on the repeatedly changing directions of the blood flow and its moving "dead point", as the peripheral resistance of arterial anastomoses-forming branches under these circumstances changes in an irregular manner.     

Mechanics of caudal artery relaxation in control and hypertensive rats

Alterations of smooth muscle function can just as easily stem from mechanical alterations in its ability to relax as from alteration in contraction. Since a failure of arterial smooth muscle to relax may contribute to the development of hypertension, we felt it necessary to study the relaxation process in greater depth. The effect of load on the time course of relaxation of rat caudal artery smooth muscle was analyzed either by comparing afterloaded contractions against various loads or by imposing abrupt alterations in load. Unlike mammalian striated muscles in which relaxation was reported sensitive to loading conditions, relaxation in the smooth muscle of the rat caudal artery (n = 17) was found to be largely independent of loading conditions. This type of relaxation has been termed "inactivation-dependent" relaxation; it is typical of muscle tissue in which the calcium sequestering apparatus is poorly developed. Our results suggest that calcium resequestration, or some biochemical process downstream to it, is the rate-limiting step during relaxation in arterial smooth muscle and that this is not qualitatively different for hypertensive arterial smooth muscle. These analytic techniques were used in the study of relaxation of hypertensive vessels. Quantitative analysis of the relaxation curves showed that both isometric and isotonic relaxation time was prolonged in hypertensive arterial smooth muscle. Prolonged isotonic relaxation indicates that hypertensive arteries remain narrowed for prolonged periods compared with normotensive vessels. Such narrowed vessels may be a factor in the increased total peripheral resistance seen in genetic hypertension.     

Rat epididymis-specific sperm maturation antigens. I. Evidence that the 26 kD 4E9 antigen found on rat caudal epididymal sperm tail is derived from a protein secreted by the epididymis

Monoclonal antibody 4E9, which was raised against a partially purified detergent extract of rat caudal epididymal sperm, recognizes the tail of sperm from the cauda, but not from caput epididymidis, as well as epithelial cells in a restricted region of the distal caput/corpus epididymidis and proteins in epididymal fluid from corpus and cauda epididymidis. The antigen is apparently a glycoprotein, since it is retained on a Ricinus communis agglutinin l lectin column. Epididymal fluid antigens have apparent M_rS of 38–26 kD, whereas the memrane-associated form of the molecule has an M_r of 26 kD. Immunocytochemical data and Western immunoblot data suggest that the membrane antigen is derived from the fluid antigen, which, in turn, is secrteted by the epididymal epithelium. Characterization of the membrane antigen indicates that it is tightly associated with the sperm surface, behaving as though it is an integral membrane protein. The antigen persists on ejaculated sperm. © 1994 Wiley-Liss, Inc.     

The development of the hypophysial portal system in the White-crowned Sparrow,Zonotrichia leucophrys gambelii

Summary The development of the hypophysial portal system has been studied in 35 embryos and 45 nestlings of the White-crowned Sparrow. The primordium of the hypophysis is vascularized by the infundibular (primary) capillary plexus, supplied by the right and left infundibular arteries, which, in the embryo, are constant branches of the right and left internal carotid arteries.The cellular proliferation and differentiation of the pars distalis into rostral and caudal lobes is accompanied by a penetration of portal vessels from the infundibular (primary) capillary plexus into these lobes beginning on the fifth day of incubation. The cellular proliferation of the rostral lobe of the pars distalis and development of the rostral group of the portal vessels precedes that of the caudal lobe of the pars distalis and the development of the caudal group of the portal vessels.The periglandular vessels, which originate in younger embryos from the infundibular (primary) capillary plexus, apparently become a part of the portal vessels.The portal vessels are the sole blood supply to the developing pars distalis of the White-crowned Sparrow; there is no evidence of a direct arterial supply at anytime during embryonic development. The neural-lobe artery appears at the end of incubation as a secondary branch of the right and left infundibular arteries. The rostral and caudal groups of the portal vessels are well-developed at the end of incubation (17–29 mm CRL) when aldehyde-fuchsin positive neurosecretory material first appears in the supraoptic and paraventricular nuclei, in the median eminence and in the neural lobe.The differentiation of the median eminence into rostral and caudal divisions begins at the end of the nestling period although its adult form is not achieved until later. The formation of the portal zone begins at the end of incubation (17–29 mm CRL) and is completed by the time of fledging.Dedicated to Professor Dr. W. Bargmann in honor of his 60th birthday.The investigations reported herein were supported by a research grant (HE 07240 NEUA) from the National Institutes of Health to Professor Vitums, by funds for biological and medical research made available by State of Washington Initiative Measure No 171 to Professor Vitums, by a research grant from the Deutsche Forschungsgemeinschaft to Professor Oksche, by aresearch grant (NB 01353) from the National Institutes of Health to Professor Farner, and by a Research Career Development Award from the National Institute of Arthritis and Metabolic Diseases (5 K 3 AM-18,370) to Professor King. We are grateful to Professor Bargmann for his generosity in making available the facilities of the Anatomisches Institut Kiel for this investigation. We wish to thank Frau Karin Graap and Mrs. Dianne Reno for technical assistance and Miss Janice Austin for the preparation of the drawings.