Luteinizing hormone and prolactin are not retrograde transferred in perihypophyseal vascular complex in ewes

The objective of the study was to determine whether luteinizing hormone (LH) and prolactin (PRL) can access the brain by way of transfer from the venous blood of the cavernous sinus to the arterial blood supplying the brain and hypophysis. Studies were performed on heads of 22 mature sheep isolated during different phases of the estrous cycle and perfused with autologous blood. We were not able to demonstrate any transfer of LH and PRL in the investigated periods. This suggests that molecular weight of hormone may be a main factor determining the permeation and transfer of hormones in the perihypophyseal vascular complex.     

Ultrastructure of the median eminence and posterior lobe of the hypophysis in newborn Diocrostonyx torquatus lemmings during a decline in the population count

Electron microscopically using morphometric analysis, the median eminence and hypophysis posterior lobe have been studied in newborn lemmings (Dicrostonyx torquatus Pallas) at the stage of decreasing population. A comparative characteristics of capillaries in the primary plexus of the portal system and capillaries of the hypophysis posterior lobe is presented. Overtaking developmental rate is demonstrated in the posterior hypophyseal lobe in comparison to that of the median eminence. In the lemmings investigated level of differentiation of the neurohemal areas of the hypothalamus is lower than development of these areas in laboratory mice and rats, according to the literature data. Possible results of weak development of the hypothalamo-hypophyseal connections in newborn lemmings at the stage of decreasing population are discussed.     

Differentiation of immunopositive ACTH cells in the human fetal pituitary gland

Differentiation and localization of corticotrophic cells in the human fetus hypophysis (5-30 weeks of development) have been studied. The immune cytochemical reaction is performed in sagittal and horizontal sections 5 mcm thick. Rabbit anti adrenocorticotrophic hormone (ACTH)-, anti ACTH- and anti ACTH-sera are used. In the hypophysis anlage of a 6-week-old fetus single immune positive ACTH-cells are revealed situating at the border where the intermediate part gets into the anterior part. With age, the number of the corticotrophic cells increases and till the first third of the intrauterine development they are mainly localized along the periphery of the epithelial cords and the adenoid- or other parts of the adenohypophysis. During the second part of the intrauterine development the corticotrophic cells localize in the same places as in a mature person. The hormone-producing ability of the hypophysis coincides with the beginning of its organogenesis.     

Effect of progesterone and estrogens on the state of the hypothalamo-hypophyseal neurosecretory system in pregnancy and labor

Morphofunctional state of the hypothalamo-hypophyseal neurosecretory system was studied in rats at late stages of pregnancy. No special differences both in function of the supraoptical and praventricular nuclei, and in the hypophysis of intact and pregnant rats at administration of progesterone were noted. When estrogenes were administered to pregnant animals, a sharp increase in functioning of the supraoptic and especially of the paraventricular nuclei was noted. The greatest activity of the supraoptic nucleus was observed at delivery that could be resulted from a stress reaction to pain.     

Humoral pathway for transfer of the boar pheromone, androstenol, from the nasal mucosa to the brain and hypophysis of gilts

Signaling and priming pheromones play an important role in intraspecies behavioral and sexual interactions and in the control of reproduction. It is generally accepted that pheromones act by stimulating the dendritic receptors in the mucus-imbedded cilia of olfactory neurons massed in the olfactory epithelium. The boar pheromone androstenol, known to induce sexual behavior in pigs, is 1 of 2 pheromones that have been chemically defined, tritiated and thus made available for use in studies. In Experiment 1, sexually mature cyclic gilts at Days 16 to 21 of the estrous cycle were humanely killed and the heads separated from the bodies. The heads were attached to a perfusion system using heated, oxygenated, heparinized, autologous blood. A total amount of 10(8) dpm (758 ng) of 3H-5 alpha-androstenol (3HA) was either infused into the angularis oculi veins that drain the nasal cavities (n = 7) over a 5-min period or applied through intranasal catheters onto the mucose surface (n = 16) for 2 min. In both groups frequent blood samples were collected from the carotid rete and from venous effluent. Concentration of 3HA in the arterial blood of the carotid rete after direct (into angularis oculi veins) or indirect (onto the nasal mucosa) administration of 3HA into veins draining the nasal cavities was significantly higher than background radioactivity before 3HA administration (P < 0.0001 and P < 0.05, respectively). The 3HA was selectively accumulated (compared with the respective control tissue) in the neurohypophysis (P < 0.001), adenohypophysis (P < 0.01), ventromedial hypothalamus (P < 0.05), corpus mammillare (P < 0.01), and perihypophyseal vascular complex (P < 0.001). In a second in vitro experiment, active uptake of 3HA into the nasal mucosa of the proximal, respiratory segment of the nasal cavity was observed. These results demonstrate a humoral pathway for the transfer of pheromones from the nasal cavity to the hypophysis and brain. Androstenol was taken up by the respiratory part of the nasal mucosa, resorbed into blood, transported to the cavernous sinus and transferred into the arterial blood of the carotid rete (supplying the hypophysis and brain), and then selectively accumulated in the hypophysis and certain brain structures.     

Hypothalamo-hypophyseal system and thyroid gland of Acipenser güldenst?dti sturgeon fry during temperature changes

In the parr of the sturgeon (body length varies from 6.1 to 14.0 cm) histometric studies have been made on the elements of hypothalamo-hypophyseal neurosecretory system, tireotropic cells (TC) of the hypophysis and the thyroid gland (TG) during the decrease of water temperature from 24--27 degrees to 10--14 degrees. It was shown that in all size groups of the fish an increase in the number, growth and differentiation of neurosecretory cells in the dorsal part of the preoptic nucleus are taking place. Correlation was found between the activity of neurosecretory cells of the dorsal part of the preoptic nucleus and hypophyseal TC. The response to the decrease in water temperature follows the pattern of stress reaction, being expressed to different extent in various size groups of the parr depending on the initial condition of the functional complex investigated.     

Problems of body structure and size of the hypophysis.

The size of the hypophysis, especially of the anterior lobe, is related to body size while the nervous lobe is related to the brain weight. The anterior lobe of the hypophysis in domestic animals is smaller than that of their ancestors in the wild. The proportions of the body, the distribution of bulk, as they appear in different races--whippets and bulldogs--are related to the size of the anterior lobe. Same body weight implies that the anterior lobe is nearly twice as large in animals with a compact body structure. These intraspecific results can also be shown interspecificly by comparing the species of African Bovidae. Independent of the influence of body size, the subfamilies Alcelaphinae and Hippotraginae possess a larger anterior lobe. A tendency can be shown for a relation to body structure as short-legged species living on marshy grounds (Kobus) or soft sands (Addax) have larger anterior lobes.     

Brain – Hatschek's pit relationships in amphioxus species

The vertebrate hypothalamo-hypophyseal neurosecretory system is a complex anatomical device for central nervous control over secretion of pituitary hormones. Since it is present in the most primitive vertebrates, the cyclostomes, it is of interest to look for a possible invertebrate anatomical equivalent, or precursor, for clues as to its evolution. We have found in six species of amphioxus, members of an invertebrate group (cephalochordates), considered to be closest to the vertebrates, that there is a morphologically equivalent neuro-epithelial complex, that in many ways resembles the hypothalamo-hypophyseal system of vertebrates. In the six amphioxus species described here the nervous element is a ventral lobe of the brain, the infundibulum, that extends downward along the right side of the notochord, and ends near the dorsal surface of a Rathke's pouch-like structure known as Hatschek's pit. This part of Hatschek's pit has been found earlier to contain a vertebrate LH-like gonadotropin. Therefore, the infundibulum-Hatschek's pit system of amphioxus may be involved in regulating the seasonal reproductive cycle, and it appears to be a direct homologue of the vertebrate hypothalamo-hypophyseal neurosecretory system functionally as well as morphologically.     

Action of testicular graft on the ovary of chick embryo having undergone a partial decapitation]

The absence of the hypothalamo-hypophyseal complex had neither influence on the ovarian atrophy, nor on the mullerian retrogression induced by an embryonic testicular graft in the female embryo. So, the hormone responsible of the mullerian retrogression had an inhibiting action on the embryonic ovary of the chick which is independant of the hypothalamo-hypophyseal complex.     

Allometry and linear correlation coefficients binding the volumes of the different pituitary gland lobes, of the pituitary gland, of the subfornical organ and of the pineal gland to body weight and to hypothalamic volume in Rodents and in a Lagomorphe]

The morphometric study of the hypophysis, of the subfornical organ and of the pineal gland of 41 Rodents and one Lagomorphe shows that the anterior lobe of the hypophysis as well as the total hypophysis are better correlated to body weight than to the volume of the hypothalamus, while it is the contrary for the pars nervosa. The volume of the intermediate lobe varies very much from one species to another for the same body weight. The high value of the allometry coefficient of the pineal gland on somatic weight (1.25) is due to the fact that the heavy Rodents of our temperate climates have a large epiphysis while the small african Rodents possess a small pineal gland.     

State of the hypothalamo-hypophyseal neurosecretory system of rabbits in anaphylactic shock]

With the aid of morphometric and histochemical methods a study was made of the hypothalamo-hypophyseal neurosecretory system of rabbits in anaphylactic shock. The following occurred in rabbits which survived the shock: an enlargement of the perikarions and reduction in the size of the nuclei and nucleoli of the neurosecretory cells; the content of the neurosecretory substance was increased in the whole neurosecretory system. In rabbits which perished from shock the nuclei and the nucleoli of the neurosecretory cells diminished to a lesser extent, perikarion measurements remained unchanged and the content of the neurosecretory substance in the posterior lobe of the hypophysis fell. Thus, in the animals which survived the shock the processes of synthesis of the neurohormones by the neurosecretory cells were sharply activated, but the secretion of the neurohormones from the posterior lobe of the hypophysis was inhibited; in animals which perished from shock the activation of the hormone formation in the neurosecretory cells was less pronounced, but the processes of the secretion of the neurohormones from the posterior lobe were apparently intensified.     

Endocrine cells share expression of N-CAM with neurones

The expression of the neural cell adhesion molecule, N-CAM, was examined in the anterior lobe of rat hypophysis by immunocytochemistry at light and electron microscope levels. In addition, N-CAM antigenic determinants present in adrenal medulla, anterior hypophysis and PC12 cells were compared by immunoblotting with those found in cerebellum. All secretory cells in the anterior hypophysis were found to be N-CAM positive on their surfaces, but not all of the three polypeptide determinants typical of cerebellum were present in the endocrine tissues or cell line tested. In addition, a new N-CAM determinant of 49 kDa not present in cerebellum was found in adrenal medulla and hypophysis, although it was absent from PC12 cells. The possible implications of these data are discussed.     

Vascularization of the pars intermedia of the hypophysis in the toad,Bufo bufo (L.) (Amphibia,Anura)

The vascularization of the pars intermedia of the hypophysis of the toad, Bufo bufo (L.) was studied by injection of a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further methyl-methacrylate corrosion casts of brains were made and the hypophysial region of the corrosion casts was examined with the scanning electron microscope. The results showed that the vascularization of the pars intermedia of the toad hypophysis consists of a single-layered vascular network, which is located on the ventral surface of the pars intermedia. The network is formed by capillaries, which primarily run caudally in a fan-like manner and which show only a few cross-connections. In the rostral region of the pars intermedia this network lies rather superficially, while in the caudal region it slightly penetrates the parenchyma. The vascular network originates from vessels of the neural stalk and from wide capillaries of the rostro-ventral region of the neurointermediate junction. The venous drainage of the pars intermedia is exerted by veins, which leave the caudal region and drain into the veins leaving the venous pole of the pars distalis. The flat, wide meshed vascular net on the ventral side of the pars intermedia, demonstrated in this study, fits into the concept that the pars intermedia of the anuran hypophysis is under the control of nerve fibers coming from the hypothalamus.     

Nuclei of the mammillary bodies and their fiber connections in cattle (Bos taurus var. domesticus). 2. Fiber connections of the mammillary bodies in cattle]

1. In the present information the course of fibre pathways which are connected with the mammillary body of the cattle is described in 14 series of brains (6 frontal, 4 sagittal, 4 horizontal series, stained by the combined cell-fibre-method after KLUVER and BARRERA and by the method for myelined fibres after HEIDENHAIN). 2. The mammillary body of cattle is connected with four main fibre systems. These are the fornix and the mamillary peduncle as well as the mamillo-thalamic and the mamillo-tegmental tracts. 3. The fornix system first of all represents a rich myelined fibre connection between the hippocampus and the mamillary body. But also fornix fibres entering the poor-myelined regions of the hypothalamus and the mesencephalon have been demonstrated. 4. The mamillary peduncle ascending from the mesencephalon can be traced to the lateral mamillary nucleus. 5. The mamillo-thalamic tract of cattle has its origin in the mamillary body with the mamillotegmental tract associated to a common principal mamillary tract and passes to the complex of the anterior nucleus of the thalamus, while the mamillo-tegmental tract branching off from it curves into the mesencephalon.     

Endocrine function of the heart. Structure and biological properties of peptides secreted by the heart atrium

Apart from the generally known functions, the heart has also an endocrine function. Atrial cardiocytes, being typical secretory cells, release peptide hormones into the blood stream: atrial natriuretic peptide containing 28 amino acids and cardiodilatin. The structure of atrial peptides was determined. It was shown that both peptides were derived from their common precursor, a protein containing 151 amino acids. The presence of specific receptors is demonstrated on plasmatic membranes of cells of kidney epithelium, arterial smooth muscle, arterial endothelium, kidney cortex and hypophysis. The interaction of atrial peptides with these receptors activates the guanylate cyclase system. The biological action of atrial peptides manifests itself in the quick, massive and instantaneous increase of diuresis and electrolyte excretion, elevated clearance of creatinine, decrease of kidney vascular resistance, intensification of glomerular filtration, inhibition of stimulated secretion of aldosterone, relaxation of blood vessels, elimination of arterial and intestinal spasm induced by various endogenous and exogenous vasoconstrictors and in correction of kidney hypertension. Various radioimmunoassays for the presence of atrial peptides in human plasma were developed; it was shown that in patients with congestive heart failure the content of atrial peptides is increased.     

Morphological characteristics of the structures delimiting the residual cavity of the hypophysis in rats after electrocoagulation of the median eminence of the hypothalamus]

By means of light and electron microscopy it has been shown that the remnant cavity of the hypophysis of intact and sham-operated rats on the side of the intermedial lobe is restricted with a continuous layer of epithelial cells with a well pronounced basal membrane. On the side of the frontal lobe the covering epithelium has peculiar "fenestra" through which adenocytes have free contacts with the remnant cavity. After electrocoagulation of the rostral area of the medial eminence, especially in remote postoperative terms, the remnant cavity enlarges up to gigantic size, contains a great amount of colloid, erythrocytes, fragments of cells of the anterior lobe of the hypophysis and secretory granules. The anterior epithelium is lacking on considerable areas and hence adenocytes are disposed in the cavity directly. All their organoids are preserved though a little changed, the cytomembrane is absent. On the apical surface of the posterior epithelium there appear large cytoplasmic protrusions which having separated enter the remnant cavity. The main provider of the "raw material" for colloid is likely to be the anterior lobe of hypophysis.     

Anatomical characteristics of the uppermost internode of winter wheat genoypes differing in stem length

Twenty one winter wheat(Triticum aestivum L.) genotypes classified as (1) short, (2) medium or (3) tall were grown in field trials. The following parameters have been measured on the main stem: stem length, peduncle length, dry mass and conducting system parameters including number of vascular bundles and their total and phloem area on peduncle cross section, ear yield and its components. Regardless of differences in peduncle length among the genotypes groups differing in stem length, the peduncle relative length varied only between 36 and 38 % of the total stem length. Nearly identical was also the peduncle specific dry mass reaching 7.4 to 7.6 mg (dry mass) per cm (peduncle length). The highest number of vascular bundles as well as the largest bundle and phloem area per peduncle cross section were found in the group of short cultivars. There was a positive correlation between the anatomical parameters and kernel number or dry mass per spike. The relationships need not be valid with each genotype because the final ear productivity is subjected to climatic variation well after anthesis when the formation of the stem anatomy has been by far accomplished.     

EXPERIMENTAL PRODUCTION OF GIGANTISM BY FEEDING THE ANTERIOR LOBE OF THE HYPOPHYSIS

1. Metamorphosed salamanders of the species Ambystoma opacum and Ambystoma tigrinum were fed on a pure diet of the anterior lobe of the hypophysis of cattle; the controls were fed on an abundant diet of earthworms. 2. The rate of growth of the animals fed on the anterior lobe of the hypophysis was greatly increased over the rate of growth of normal animals. 3. Growth of the animals fed on anterior lobe did not cease after they had reached the normal "maximum" size of the species, and experimental giants were produced. 4. The largest animal of the species Ambystoma opacum fed on anterior lobe of the hypophysis was 19 mm. larger than the largest normal animal of this species known to the writer; the largest animal of the species Ambystoma tigrinum fed on anterior lobe is at present about 28 mm. larger than the largest normal animal of the eastern race of this species known to the writer.     

Ultrastructural and immunoelectron-microscopic study of the human pharyngeal hypophysis

The ultrastructural characterization of seven cell types in the pharyngeal hypophysis from adult subjects is described. By immunoelectron microscopy, two of the granular cell types were identified as growth-hormone- and prolactin-producing cells. The vascular supply of this gland was mainly composed of capillaries without fenestrations. Review of the literature allows a comparison with the ultrastructure of the sellar adenohypophysis and with the pharyngeal hypophysis of children.