The effects of adrenalectomy and corticosterone replacement on maternal memory in postpartum rats

Hormones associated with parturition prime rats to behave maternally, although hormonal changes are not necessary for these behaviors to occur. Experience with pups after birth enhances maternal responsiveness after a period of isolation, creating a maternal memory. The purpose of this study was to determine the role of corticosterone in the formation of maternal memory. Adrenalectomy or sham surgeries were performed in late gestation with corticosterone or vehicle pellets being given to adrenalectomized rats. Pups were removed immediately following parturition, and half of the rats received 4 h of pup experience, while the other half received only brief pup experience associated with parturition. Ten days following pup experience, foster pups were given to all rats. Latency to become maternal and maternal behaviors on the first 2 days of re-exposure and the first two maternal days were recorded. Among adrenalectomized rats given corticosterone, 4-h experience with pups decreased maternal latency when compared to brief experience with pups. This maternal experience effect was not found in comparisons between adrenalectomized rats not given corticosterone. In addition, corticosterone decreased latencies regardless of pup experience. Corticosterone also increased maternal behavior upon initial exposure to foster pups. In conclusion, corticosterone enhanced maternal memory and initial maternal behavior in postpartum rats.     

The effects of adrenalectomy and corticosterone replacement on maternal behavior in the postpartum rat

It is well known that the hypothalamic-pituitary-adrenal (HPA) axis is activated during stress. Recent work suggests it is also implicated in the regulation of "normal" behaviors. The present studies investigated the effects of adrenalectomy and of varying glucocorticoid concentrations on adult maternal behavior in primiparous rats. In two studies, rats in late pregnancy were adrenalectomized or given sham surgeries and were tested for maternal behavior. In the first study, primiparous rats were given 0, 25, 100, 300, or 500 microg/ml of corticosterone in their drinking water. In the second study, primiparous rats were given either control or corticosterone time-release pellets. Blood samples were taken to ensure that rats demonstrated levels of corticosterone in blood that were relative to doses received. In studies one and two, primiparous adrenalectomized rats showed slightly, but significantly, lower levels of some maternal behaviors, including licking and time in nest, than primiparous sham rats. Primiparous rats given higher doses of corticosterone replacement showed higher levels of these maternal behaviors than primiparous rats given lower doses of corticosterone. In conclusion, adrenalectomy decreases, but does not abolish, maternal behavior. Corticosterone replacement reverses these effects. Corticosterone is not necessary for the initiation or maintenance of maternal behavior but plays a role in the modulation of ongoing maternal behavior.     

The ultrastructure of the human fetal pineal gland

Summary The ultrastructure of the pineal gland of 18 human fetuses (crown-rump lengths 30–178 mm) was investigated.The pineal gland exhibits a pyramidal shape and consists of an anterior and posterior lobe. Only one parenchymal cell type, the pinealocyte, was observed. Few neuroblasts were seen between the pinealocytes and in the extended perivascular space. The pinealocytes possess all the organelles necessary for hormone synthesis. No specific secretory granule could be observed. The organ is abundantly vascularized and richly innervated. The morphology of the capillaries indicates the existence of a blood-brain barrier.The ultrastructure of the human fetal pineal gland suggests that the gland has a secretory function in early intrauterine life. Acknowledgements. The author is grateful to Mrs. Yael Balslev and Miss Inger Ægidius for their able technical assistance. This investigation was supported in part by The Carl and Ellen Hertz's foundation and the Johann and Hanne Weimann foundation.     

The ultrastructure of the accessory sex organs of the male rat

Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components.Changes in the nucleoplasm were primarily reflected by a condensation of chromatin, particularly along the nuclear membrane and adjacent to the nucleolus. Later, different types of intranuclear inclusions were observed.After 21 days, the nuclei were characterized by an irregular outline with large indentation. Within the nucleoplasm aggregates of coarse granular chromatin were found. No cell necrosis was observed, indicating that androgen deprivation results in a remodeling of the cell to a less active state with marked cellular alterations and cessation of secretion, but apparently with some of their basic functions still intact.Injections of testosterone completely reverse the castrated-induced alterations.The changes observed are assumed to be due to the withdrawal of the androgenic stimulus, with a direct influence on the secretory function of the cell. The findings support the view that the stimulating secretory effect of androgen is mediated via an intranuclear androgen receptor, probably located in the nucleolus-associated-chromatin. It is also proposed that the secretory function of the epithelial cells of the prostatic complex, initiated by androgens, may be regulated by an intranuclear secretory center.     

The effects of niamid and reserpine on the nerve endings of the pineal gland

Summary Kitten pineal glands were studied cytochemically under normal conditions, after reserpine injection, and after niamid administration. Adrenergic nerve elements were in perivascular spaces while cholinergic terminals were adjacent to pinealocytes, often times in synaptic contact. BA reactions are primarily in dotted vesicles of adrenergic terminals with some reaction in granular vesicles. Positive reaction occurs along neurotubules and membranous structures of adrenergig nerve fibers and terminals indicating membrane-bounded BA's. Niamid increased the number and density of dotted vesicles, and some granular vesicles are increased in density and size. Reserpine produced a loss reaction in dotted vesicles and a loss of vesicle matrix, producing elliptical vesicles. There is loss of reaction of the dotted vesicles, but occasionally, the positive granular reaction remains. Cholinergic terminals demonstrate no changes with either niamid or reserpine. These findings indicate BAs are stored in reserpine sensitive dotted vesicles and membraneous structures. The findings also show that the dotted vesicle matrix is reserpine sensitive and is necessary for storage of the BA's. Possibly biogenic amines cannot be stored or synthesized in terminals unless the matrix of the dotted vesicle is intact.Supported by: HEW Grant No. NS-10326. The University of Texas Medical School at Houston. — Special appreciation to Mrs. Charlotte Smith for her valuable technical assistance. Appreciation to Ciba-Geigy Corporation for supply of Serpasil (reserpine).     

Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure

Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.     

The effects of adrenalectomy and corticosterone replacement on induction of maternal behavior in the virgin female rat

Maternal behavior of the sensitized virgin rat is affected by approach-avoidance systems as well as by hypothalamic-pituitary-adrenal (HPA) axis, which is also activated during stress. The present experiments investigated the effects of adrenalectomy and of varying corticosterone concentrations on the onset and expression of maternal behavior in sensitized virgin rats. In the first experiment, latency to onset of maternal behavior and time spent licking once maternal were positively related to endogenous levels of corticosterone. However, few rats showed licking. In the second experiment, virgin rats were adrenalectomized or given sham surgeries before being sensitized and being given 0, 25, 100, 300, or 500 microg/mL of corticosterone in their drinking water. In the third experiment, virgin rats were adrenalectomized or given sham surgeries and given either control or corticosterone time-release pellets after being sensitized. Maternal behavior was then tested. Adrenalectomy increased licking in the second experiment and time over pups in the third experiment. Corticosterone replacement reduced licking in the second experiment and both licking and time over pups in the third experiment. In conclusion, exogenous corticosterone had an inhibitory effect on the expression of maternal behavior in the sensitized virgin rat, unlike the facilitatory effect previously found in the postpartum rat.     

The ultrastructure of the accessory sex organs of the male rat

Summary The seminal vesicles and the coagulating gland of the rat were studied 2, 3, 5, 7 and 21 days after castration. The major changes within the seminal vesicles were primarily formation of whorls of the rough endoplasmic reticulum (RER), followed by a general atrophy with a numerical reduction of the RER-profiles, and with general simplification of the cytoplasm due to loss of the organelles. It was a gradually reduction of secretion granules, diminution of the Golgi apparatus, formation of pigment bodies and autophagic vacuoles. Lipid droplets were observed in the basal cytoplasm of the epithelial cells. In the coagulating gland, similar changes occurred within the Golgi area and the lysosome complex. On the other hand, cisternae of the basal endoplasmic reticulum tended to persist in many cells. The similarity in response strongly suggests that the pathogenetic mechanisms are similar in both organs, i.e. atrophy due to deprivation of the androgenic stimulus. The deprivation of androgen gave rise to an inflammatory-like process with infiltration of lymphocytes and macrophages. The increased number of macrophages may indicate that they contribute in some way to the involution of the prostate by removing the material in the autophagic vacuoles.     

Fine structure and innervation of the avian adrenal gland

Summary According to their ultrastructure and histochemistry three types of efferent nerve fibers can be distinguished in the bird's adrenal gland. The main part is made up of cholinergic fibers recognizable by a positive reaction for acetylcholinesterase and two specific populations of granules within the synaptic ending. Synaptic vesicles measuring 300 to 500 Å in diameter and dense-cored vesicles with a diameter of about 1 000 Å are discernible.In the periphery of the gland cholinergic axons for the innervation of adrenal cells form large bundles surrounded by a perineural sheath. The bundles cross the capsule and are situated within the adrenal chromaffin cords or at their periphery. Finally small groups of fibers enter a group of chromaffin cells which are surrounded by a basal lamina and which consist of about a dozen or more cells producing adrenaline and noradrenaline. Synaptic endings occur, above all in passeriform species, in the center of a chromaffin cell complex. They are either attached to the innervated cells or their dendrite-like processes, or embedded into the cells, or connected to short spines of the innervated cells. Synaptic and dense-cored vesicles leave the bouton by exocytosis. One synaptic terminal may innervate up to three A- or NA-cells. The existence of different types of synapses for A- and NA-cells cannot be excluded.Supported by a grant from the Deutsche Forschungsgemeinschaft (Un 34/1).     

Fine structure and innervation of the avian adrenal gland

Summary Apart from cholinergic nerve fibers, which make up the main part of efferent fibers to the avian adrenal gland (Unsicker, 1973b), adrenergic, purinergic and afferent nerve fibers occur. Adrenergic nerve fibers are much more rare than cholinergic fibers. With the Falck-Hillarp fluorescence method they can be demonstrated in the capsule of the gland, in the pericapsular tissue and near blood vessels. By their green fluorescent varicosities they may be distinguished characteristically from undulating yellow fluorescent ramifications of small nerve cells which are found in the ganglia of the adrenal gland and below the capsule. The varicosities of adrenergic axons exhibit small (450 to 700 Å in diameter) and large (900 to 1300 Å in diameter) granular vesicles with a dense core which is usually situated excentrically. After the application of 6-hydroxydopamine degenerative changes appear in the varicosities. Adrenergic axons are not confined to blood vessels but can be found as well in close proximity of chromaffin cells. Probably adrenergic fibers are the axons of large ganglion cells which are situated mainly within the ganglia of the adrenal gland and in the periphery of the organ and whose dendritic endings show small granular vesicles after treatment with 6-OHDA.A third type of nerve fiber is characterized by varicosities containing dense-cored vesicles with a thin light halo, the mean diameter (1250 Å) of which exceeds that of the morphologically similar granular vesicles in cholinergic synapses. Those fibers resemble neurosecretory and purinergic axons and are therefore called p-type fibers. They cannot be stained with chromalum-hematoxyline-phloxine. Axon dilations showing aggregates of mitochondria, myelin bodies and dense-cored vesicles of different shape and diameter are considered to be afferent nerve endings. Blood vessels in the capsule of the gland are innervated by both cholinergic and adrenergic fibers.Supported by a grant from the Deutsche Forschungsgemeinschaft (Un 34/1).     

Zona glomerulosa of the adrenal gland in a transgenic strain of rat: a morphologic and functional study

Transgenic rats for the murine Ren-2 gene display high blood pressure, low circulating levels of angiotensin II, and high renin content in the adrenal glands. Moreover, transgenic rats possess and increased aldosterone secretion (maximal from 6 to 18 weeks of age), paralleling the development of hypertension. To investigate further the cytophysiology of the adrenal glands of this strain of rats, we performed a combined morphometric and functional study of the zona glomerulosa of 10-week-old female transgenic rats. Morphometry did not reveal notable differences between zona glomerulosa cells of transgenic and age- and sex-matched Sprague-Dawley rats, with the exception of a marked accumulation of lipid droplets, in which cholesterol and cholesterol esters are stored. The volume of the lipid-droplet compartment underwent a significant decrease when transgenic rats were previously injected with angiotensin II or ACTH. Dispersed zona glomerulosa cells of transgenic rats showed a significantly higher basal aldosterone secretion, but their response to angiotensin II and ACTH was similar to that of Sprague-Dawley animals. Angiotensin II-receptor number and affinity were not dissimilar in zona glomerulosa cells of transgenic and Sprague-Dawley rats. These data suggest that the sustained stimulation of the adrenal renin-angiotensin system in transgenic animals causes an increase in the accumulation in zona glomerulosa cells of cholesterol available for steroidogenesis, as indicated by the expanded volume of the lipid-droplet compartment and the elevated basal steroidogenesis. However, the basal hyperfunction of the zona glomerulosa in transgenic animals does not appear to be coupled with an enhanced responsivity to its main secretagogues, at least in terms of aldosterone secretion.     

Influence of short photoperiods on the ultrastructure of hamster Harderian glands

Summary A sexual dimorphism of the hamster Harderian gland at the ultrastructural level, has been reported. Castration of males and the administration of testosterone to females are known to alter the male type gland to the female type and vice versa. In this paper we present data that exposure to a short photoperiod (1L:23D) can induce similar structural alterations between the 4th and 10th week of exposure. Changes in the male included reduction in the number of tubular clusters and large vacuoles, while in the female the number of membrane formations decreased with an accompanying appearance of tubular clusters.     

Secretion in the rat coagulating gland (Anterior Prostate) after copulation

Summary The effect of copulation on the rat coagulating gland (anterior prostate) was studied. At 4 to 6 h after the beginning of copulation the coagulating glands of rats that had produced copulatory plugs were nearly empty of secretion. Ultrastructurally, the coagulating gland has large cisternae of rough endoplasmic reticulum (RER) and few condensing vacuoles or secretion granules. After copulation the number of secretion granules and the frequency of their expulsion into the lumen increased. Also in the lumen were fragmentation vesicles (50–100 nm diameter) that were bounded by a unit membrane and appeared to arise from microvilli. At 4, 6, and 7h after the beginning of copulation there was an increase in apical blebbing. Blebbing was found in both perfusion and immersion-fixed tissue. Also, after copulation there was an increase in light cells that were characterized by reduced RER cisternae, an electron lucent cytoplasm, and atrophic Golgi apparatus. The luminal ground substance, secretion granules, and some Golgi elements, contained polysaccharides as seen with the periodic acid-thiocarbohydrazide-silver proteinate method.     

Immunocytochemical localization of a growth-associated protein (GAP-43) in rat adrenal gland

We have localized at light and electron-microscopic level the growth-associated protein GAP-43 in adrenal gland using single and double labelling immunocytochemistry. Clusters of GAP-43-immunofluorescent chromaffin cells and many immunofluorescent fibres were observed in the medulla. GAP-43-immunoreactive fibres also formed a plexus under the capsule, crossed the cortex and ramified in the zona reticulata. Double labelled sections showed the coexpression of GAP-43 with a subpopulation of tyrosine hydroxylase-and of dopamine--hydroxylase-immunoreactive chromaffin cells. Dual colour immunofluorescence for GAP-43 and calcitonin gene-related peptide (CGRP) revealed that some of the GAP-43-immunoreactive fibres also express CGRP. Pre-embedding electron microscopy showed GAP-43 immunoreactivity associated with the plasma membranes and cytoplasm of noradrenaline-producing chromaffin cells, and with processes of nonmyelin-forming Schwann cells. Immunoreactive unmyelinated axons and terminals were also observed. The immunostained terminals made symmetrical synaptic contacts with chromaffin cells. Immunoreactive unmyelinated fibres and small terminals were present in the cortex. Our results show that GAP-43 is expressed in noradrenergic chromaffin cells and in various types of nerve fibres that innervate the adrenal. Likely origins for these fibres include preganglionic sympathetic fibres which innervate chromaffin cells, postganglionic sympathetic fibres in the cortex, and CGRP containing sensory fibres.     

Effect of cycloheximide on the fine structure of corpus luteum in intact and hypophysectomized rats

Summary In rats, one large intravenous dose of cycloheximide leads to extensive development of two types of membrane-formations in the cells of corpora lutea, within two hours. Both the laminated dense bodies (concentric layers of smooth membranes showing high electron density) and the tubular aggregates (tightly packed smooth tubules with diameter smaller than usual) exhibited obvious connections with endoplasmic reticulum membranes. The reorganization of tubular aggregates gave rise to crystalloids showing hexagonal symmetry. The crystalloids, being obviously unstable, were transformed into smooth fingerprints (concentric arrays of paired agranular membranes showing the same density as endoplasmic reticulum membranes). Hypophysectomy, performed 24 hours previously, moderated but did not totally abolish the development of membranous configurations. The described effect of cycloheximide is considered to represent cellular injury, probably due to membrane-denaturation.This work was supported in part by the Medical Research Council of Canada (Block Term Grant MT-1829), the Ministère des Affaires Sociales, Quebec, and Succession J.A. DeSève. The authors thank the Upjohn Company, Kalamazoo, Michigan, U.S.A., for the cycloheximide used in these experiments.Fellow of the Medical Research Council of Canada.     

Acinar ultrastructure of the submandibular gland of Mus musculus during embryonic development

Summary The development of the submandibular gland of the mouse was studied by means of electron microscopy, from the 14th day of gestation up to birth. In the first two days the acini are solid and their cells contain polyribosomes and a few lamellae of endoplasmic reticulum. Beginning with the 16th day secretory granules appear and rapidly fill an increasing number of cells. The different electron density of the granules makes it possible to distinguish 1. two types of granules, dense and pale, and sometimes intermediate ones, 2. polymorphic granules. The latter consists of electron dense and electron pale parts combined in different configurations. The possible significance of the various types of granules is discussed.     

Effects of adrenalectomy and of adrenal hormones on the tissue distribution of 14 elements in the rat

The effects of adrenalectomy (ADY) and of replacement therapy using a mineralocorticoid, deoxycorticosterone (DOC) and a glucocorticoid, dexamethasone (DEX) on the tissue distribution of elements in the rat, were studied under semichronic conditions. The elements, Na, K, Ca, Mg, Fe, S, P, Rb, Sr, Mn, Cu, and Zn were determined in whole blood, plasma, brain liver, kidney, heart, skeletal muscle, spleen, thymus, and bone. Additionally Mo was determined in kidney and liver and Ba in bone. ADY modified concentrations of all elements tested. Small changes were observed for K, Mg, Ca, S, and P, whereas much larger changes were noted for Na, Rb, and Sr. Cu, Zn, and Fe were mainly modified in liver and kidney, organs involved in storage and/or elimination. The consequences of ADY were corrected fairly well by DEX for Mg, Mn, Ca, Cu, and Mo; by DOC for Na and K, and by the two corticoids for Zn, Fe, Sr, and Rb. This study revealed that corticoids, mainly glucocorticoids, play an important role in the plasma and tissue balance of elements. It is suggested that these results may have a pathological and clinical significance.     

Effects of maternal deprivation on adrenal and behavioural responses in rats with anterodorsal thalami nuclei lesions

There is evidence that repeated maternal isolation of neonatal rats may influence both emotional behavior and Hypothalamic-Pituitary Adrenal (HPA) activity. On the other hand the Anterodorsal Thalami Nuclei (ADTN) exerts an inhibitory influence on the hypophyso-adrenal system under basal and stressful conditions. In the present work we investigated whether neonatal maternal deprivation produces long term effects on the ADTN regulation of behavioral patterns (open field test) and on HPA axis activity. Specifically, we sought to determine whether adult female rats with ADTN lesions, previously isolated for 4.5 hours daily during the first 3 weeks of life, react in endocrinologically and behaviourally distinct manner as compared to controls. The examined groups were: non maternally deprived (NMD)/sham lesioned, NMD/lesioned, maternally deprived (MD)/sham lesioned, MD/lesioned with and without the open field test. At 3 months MD/sham lesioned animals showed a marked decrease in ambulation (P < 0.01), and with ADTN lesion, the rearing values were lower (P < 0.01) and grooming higher (P < 0.05) than NMD. This last data would indicate a high emotional index. Regarding the activity of the HPA axis, maternal deprivation induced a significant decrease in plasma ACTH concentration both in sham and lesioned animals (P < 0.001), and plasma Corticosterone (C) increased in sham animals (P < 0.001). This data would indicate a higher sensitivity of the adrenal glands. After the open field test ACTH and C were different between deprived and non-deprived animals depending on the ADTN lesion. Taking into consideration the increase of ACTH levels in sham lesioned MD animals exposed to the test, we could conclude that this new situation was a stressful situation. Finally in the present work, it was very difficult to relate the behavioral parameters with the endocrine data. It is known that depending on the context, corticosteroids may produce opposite effects on emotional behavior via different receptors in the brain.In summary, neonatal maternal deprivation induced alterations of behavioral patterns and affected the ADTN inhibitory influence on ACTH and C secretion.     

Recent observations on the ultrastructure of human urothelium

Summary An electron microscopic study of normal bladder urothelium of elderly patients ranging in age from 61 to 82 years has shown the occurrence of unusually thin regions consisting of either one or two layers of undifferentiated cells interspersed between 3–4 cell layers thick regions. A morphometric study has confirmed the existence of a pattern of cytodifferentiation in cells of the thick region. The generally microvillous nature of the luminal surface is attributed to incompletely differentiated cells that have come to occupy the superficial layer. The lack of thickened and/or asymmetric membrane plaques in luminal plasma as well as the dearth of characteristic precursor vesicles in the cytoplasm are also explicable in terms of a failure of normal cell differentiation. It is suggested that the unusual features noted are consequences of tissue ageing rather than prognostic of cancer. There are indications that the aged urothelium may be prone to increased leakiness and the bladder tissues may therefore be at greater risk from urine-borne chemicals and carcinogens.     

Evidence that an extrahypothalamic pituitary corticotropin-releasing hormone (CRH)/adrenocorticotropin (ACTH) system controls adrenal growth and secretion in rats

Within two weeks, hypophysectomy induced in rats a striking decrease in the level of circulating ACTH (the concentration of which was at the limit of sensitivity of our assay system), coupled with a net reduction in the plasma corticosterone concentration and an evident adrenal atrophy. Zona fasciculata, the main producer of glucocorticoids, was decreased in volume, due to a lowering in both the number and average volume of its parenchymal cells. Subcutaneous ACTH infusion (0.1 pmol·min^-1), administered during the last week following hypophysectomy, restored the normal blood level of ACTH and completely reversed all effects of hypophysectomy on the adrenals. Subcutaneous infusion for one week with -helical-CRH or corticotropin-inhibiting peptide (1 nmol·min^-1), which are competitive inhibitors of CRH and ACTH, evoked a further significant lowering of plasma corticosterone concentration and markedly enhanced adrenal atrophy in hypophysectomized rats. These findings strongly suggest that an extrahypothalamic pituitary CRH/ACTH system may be involved in the maintenance of the growth and steroidogenic secretory activity of the rat adrenal cortex.