Infradian rhythm of secretory activity and calcification pineal gland in experiment

2020 ◽  
pp. 18-20
Author(s):  
A.V. Gerasimov ◽  
D.K. Garmaeva ◽  
S.A. Fedorova ◽  
V.P. Kostyuchenko ◽  
A.V. Potapov ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Secretory Activity ◽  
Infradian Rhythm

FURTHER STUDIES ON PRENATAL FUNCTIONAL RELATIONS BETWEEN RAT PINEAL GLAND AND EPITHELIUM OF LOWER ILEUM

1964 ◽  
Vol 47 (3) ◽  
pp. 500-516 ◽  
Author(s):  
Christer Owman
Keyword(s):  
Pineal Gland ◽  
Secretory Activity ◽  
In Utero ◽  
Intact Proteins ◽  
Functional Relations ◽  
Pineal Function ◽  
Protein Nature ◽  
Eosinophilic Inclusions ◽  
Rat Pineal Gland ◽  
Lower Ileum

ABSTRACT It has previously been demonstrated by the author that the developing pineal gland of the rat possesses functional activity during a definite period. Destruction of the active gland in utero regularly causes marked changes in the lower ileum, the epithelial cells being filled with large eosinophilic inclusions of carbohydrate-protein nature. These inclusions are a manifestation of the absorption of muco- or glycoproteins from the amniotic fluid, known to be ingested by the foetus. In the present study, pinealectomy in utero was performed by electrocoagulation on forty-eight foetuses at certain specific stages. Twenty-six foetuses were sham-operated. For comparison, seventy-two unoperated controls were analyzed. The stage at which the inclusions first appear after pinealectomy is determined and discussed. Furthermore, the foetuses have been analyzed near the expected term after pinealectomy at different stages. Destruction of the gland before pineal secretory activity causes very marked changes in the ileal epithelium; these are less distinct when the operation is performed during the secretory period. Pinealectomy after the secretory period does not cause any changes in the lower ileum in comparison with sham-operated control foetuses. Thus, a remote action has been demonstrated for the foetal pineal gland. The function seems to be that of preventing significant intestinal absorption of intact proteins while the foetus is still within the uterus. After birth such absorption is known to occur normally from colostrum. The possible connection of the foetal adrenals to the prenatal pineal function is discussed.

scholarly journals The effects of treatment with melatonin on the ultrastructure of mouse leydig cells: a quantitative study

2002 ◽  
Vol 62 (3) ◽  
pp. 517-523 ◽  
Author(s):  
C. A. REDINS ◽  
G. M. REDINS ◽  
J. C. NOVAES
Keyword(s):  
Pineal Gland ◽  
Leydig Cells ◽  
Direct Action ◽  
Secretory Activity ◽  
Nuclear Volume ◽  
Sham Control ◽  
Subcutaneous Injections ◽  
Testosterone Secretion ◽  
Transmission Electron

Both the presence of receptors for gonadal steroids in the pineal gland and in vitro observations of direct action of melatonin upon Leydig cells, inhibiting testosterone secretion, indicate a direct connection between pineal gland and gonadal function. In the present study, we used a transmission electron microscope to analyze the morphologic parameters of Leydig cells from adult Swiss outbred white mice treated with daily subcutaneous injections of 100 µg of melatonin (N-acetyl, 5-methoxytryptamine), during 22 consecutive days, compared with sham-control animals which had only received the melatonin vehicle. The melatonin group of mice showed a decrease in nuclear volume and fractional nuclear volume; smooth and rough endoplasmic reticulum; mitochondria; and Golgi complex. Our data also showed an increase in cytoplasmic volume, fractional cytoplasmic volume, and lysosomes in these same animals. The results suggest that melatonin, directly or indirectly, alters the ultrastructure of mouse Leydig cells and possibly influences their secretory activity by inhibiting their capacity to secrete steroids.

EFFECTS OF SHEEP AND YOUNG CALF PINEAL EXTRACTS AND CONTINUOUS LIGHT ON THE PINEAL GLAND, THE GONADS AND THE OESTROUS CYCLE OF THE RAT

1968 ◽  
Vol 57 (4) ◽  
pp. 585-594 ◽  
Author(s):  
N. Prop ◽  
I. Ebels
Keyword(s):  
Pineal Gland ◽  
Continuous Light ◽  
Secretory Activity ◽  
Young Female ◽  
Oestrous Cycle ◽  
Water Soluble ◽  
Female Rats ◽  
Pineal Extract ◽  
Water Soluble Extract ◽  
Pineal Extracts

ABSTRACT Injections of a water-soluble pineal extract into young female rats kept under a normal light/dark rhythm caused a relatively high frequency of abnormal nuclei in the pineal gland. This nuclear response suggests a secretory activity in normal pinealocytes. No effect of the pineal extract on the reproductive system was observed. In females exposed to continuous light, neither the water-soluble extract nor the acetone-soluble pineal material interfered with the light induced alterations in the oestrous cycle, the uterine and ovarian weights, the condition of the pineal nuclei and the quantity of pineal lipids.

scholarly journals The effect of treatment with melatonin upon the ultrastructure of the mouse pineal gland: a quantitative study

2001 ◽  
Vol 61 (4) ◽  
pp. 679-684 ◽  
Author(s):  
G. M. REDINS ◽  
C. A. REDINS ◽  
J. C. NOVAES
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pineal Gland ◽  
Quantitative Study ◽  
Subcutaneous Injection ◽  
Secretory Activity ◽  
Secretory Process ◽  
Volumetric Density ◽  
Transmission Electron ◽  
Effect Of Treatment

In order to evaluate melatonin implication in the regulating of its own secretory process by pinealocytes, we used morphometric techniques for transmission electron microscopy. In mice treated with 100 mg of melatonin (N-acetyl-5-methoxy-tryptamine) by daily subcutaneous injection, we observed a decrease in number and volumetric density of lysosomes. Our results showed that melatonin influences the secretory activity of pinealocytes and participates in a complex secretory regulating mechanism.

scholarly journals Role of AA-NAT and TPH1 in the Ghrelin-Dependent Regulation of Melatonin Secretion in Sheep during Different Seasons: An In Vitro Study

2017 ◽  
Author(s):  
Katarzyna Kirsz ◽  
Malgorzata Szczesna ◽  
Dorota A. Zieba
Keyword(s):  
Food Intake ◽  
Pineal Gland ◽  
Real Time Pcr ◽  
Secretory Activity ◽  
Melatonin Secretion ◽  
Independent Manner ◽  
Phosphorylated Form ◽  
Different Seasons

Several studies suggests that ghrelin (GHRL) has neurobiological effects that extend beyond control of food intake. Our previous results confirmed that GHRL modulates the secretory activity of the pineal gland (PG) through nocturnal melatonin (MEL) secretion in sheep, the seasonally reproductive animals. Here we investigated the effects of GHRL (10 ng/ml) on the expression of enzymes limiting synthesis of MEL, including tryptophan 5-hydroxylase 1 (TPH1), serotonin N-acetyltransferase (AA-NAT) and its phosphorylated form p31T-AA-NAT in sheep PG explants (n = 72) during the 4-hour incubation in a gas-liquid interface, at a short (SD) and long (LD) photoperiods. After each hour of incubation selected explants were frozen in liquid nitrogen and stored at -80°C for subsequent analysis (real-time PCR, western-blotting, ELISA). Results show that GHRL regulates nightly MEL secretion in a TPH1-independent manner. The factor modulating GHRL activity was photoperiod. During SD photoperiod GHRL significantly reduced the expression of p31T-AA-NAT, AA-NAT and inhibited MEL secretion from PG explants. Whereas, during LD photoperiod no effect of GHRL on MEL secretion and expression of examined enzymes was noted. Studies indicate that GHRL directly affects PG under in vitro conditions and causes MEL secretion in animals which exhibit seasonality in reproductive and metabolic processes.

The Dermal Glands of Rhodnius Prolixus

1969 ◽  
Vol 27 ◽  
pp. 258-259
Author(s):  
J. E. Lai-Fook
Keyword(s):  
Fine Structure ◽  
Secretory Activity ◽  
Rhodnius Prolixus ◽  
Outermost Layer ◽  
Cement Layer ◽  
Dermal Glands

Dermal glands are epidermal derivatives which are reported to secrete either the cement layer, which is the outermost layer of the epicuticle or some component of the moulting fluid which digests the endocuticle. The secretions do not show well-defined staining reactions and therefore they have not been positively identified. This has contributed to another difficulty, namely, that of determining the time of secretory activity. This description of the fine structure of the developing glands in Rhodnius was undertaken to determine the time of activity, with a view to investigating their function.

Ultrastructural Aspects of Golgi Complex Function in Parathyroid Cells of Winter Frogs

1973 ◽  
Vol 31 ◽  
pp. 680-681
Author(s):  
William J. Dougherty
Keyword(s):  
Golgi Complex ◽  
Secretory Granules ◽  
Complex Function ◽  
Secretory Activity ◽  
Secretory Proteins ◽  
Perivascular Spaces ◽  
Pituitary Cells ◽  
Electron Microscopic ◽  
Ca Ions ◽  
Regulation Of Secretion

The regulation of secretion in exocrine and endocrine cells has long been of interest. Electron microscopic and other studies have demonstrated that secretory proteins synthesized on ribosomes are transported by the rough ER to the Golgi complex where they are concentrated into secretory granules. During active secretion, secretory granules fuse with the cell membrane, liberating and discharging their contents into the perivascular spaces. When secretory activity is suppressed in anterior pituitary cells, undischarged secretory granules may be degraded by lysosomes. In the parathyroid gland, evidence indicates that the level of blood Ca ions regulates both the production and release of parathormone. Thus, when serum Ca is low, synthesis and release of parathormone are both stimulated; when serum Ca is elevated, these processes are inhibited.

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

1975 ◽  
Vol 33 ◽  
pp. 378-379
Author(s):  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Pituitary Adenomas ◽  
Secretory Activity ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Cytoplasmic Staining ◽  
Human Pituitary Gland ◽  
Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

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