MORPHOMETRY OF THE HUMAN PINEAL GLAND: RELATIONSHIP TO THE ADRENAL CORTEX

To investigate the role of the pineal gland in the endocrine system, we examined 26 autopsy cases dying from non-neoplastic diseases. The study was carried out on the hypothetic basis of the possible influences of the pineal gland on the pituitary-ad renal axis, which we believe to be existing also in man. Measurements on the pineal gland revealed that the weight of the gland was directly proportional to the volume (r=0.94; P<0.001) and also to the nuclear density of the parenchyme (r=0.65; P<0.01). Then, the interrelationship between the weight of the pineal gland and the thickness of the adrenal cortex was determined (r=-0.56; P<0.05). The pineal gland was significantly larger in weight in the prednisolone treated patients (166±66 mg, [±SD]) than in the others (97±52 mg; P<0.05). We conclude that the functional antagonism exists between the pineal gland and the adrenal cortex in man, although the mechanism involved has not been clarified yet.     

Effect of 3-acetylpyridine on adrenocortical function

The corticosteroid concentration in the blood of rats was found to be lowered after injection of 3-acetylpyridine. In rats previously given 3-acetylpyridine, ACTH reduced the fall in the corticosteroid level in the blood and adrenal tissue compared with that in intact animals. Glucose-6-phosphate dehydrogenase activity in the adrenals was reduced after administration of 3-acetylpyridine. It is suggested that 3-acetylpyridine exerts its action at the adrenal level by inhibiting NADPH generation in dehydrogenase system.Department of Regulation of Metabolism, Academy of Sciences of the Belorussian SSR, Grodno. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 2, pp. 161–162, February, 1977.     

Effects of intracranial surgery on pineal lipid droplets, on other structures, and on melatonin secretion

Unique effects of sham-pinealectomy [intracranial surgery (IS)] which include reduced functional activity of the adrenal gland and suppressed circadian rhythms of the adrenal medulla, and which are reversed by pinealectomy, have been reported in rodents. To clarify the mechanisms, we investigated whether or what changes occur in pineal functional activity after IS. Sixty-six male rats of normal and IS groups were used at 50 days of age. The pineal gland was first examined by quantitative electron microscopy. The Sudan III-stained lipid droplet content of the pinealocytes and plasma melatonin level were then investigated using the same animals. In IS rats, the lipid droplet content of the pinealocytes decreased in both the dark and light phases 14 days after surgery. Mean volumetric ratio of nucleus, nucleolus, and mitochondria tended to increase in IS rats. The mean plasma concentration of melatonin showed apparent day–night changes, but no significant changes because of IS, 36 h and 14 days after surgery. But in the dark phase 14 days after surgery, plasma melatonin levels showed increased dispersion of values (P < 0.04). Thus, after IS the lipid content of pinealocytes showed changes not closely related to those of plasma melatonin level. From these and other results it is speculated that IS effects are dissimilar to usual stress responses, that day–night rhythms of functional activities of the pineal and adrenal medulla are differently controlled, and that pineal gland-dependent IS effects are most probably induced by changed sensitivity/states of target mechanisms to the pineal hormone melatonin.     

Application of confocal laser scanning microscopy to the deep pineal gland and other neural tissues.

The study of the deep pineal gland of the Mongolian gerbil and other neuronal tissue from the rat by means of confocal laser scanning microscopy (CLSM) is described. Opical serial sectioning was performed on thick (100-200 microns) sections of the deep pineal gland of the Mongolian gerbil stained immunohistochemically using antisera to S-antigen and tyrosine hydroxylase (TH). Both dual-stained and single-stained material was examined using the fluorochromes fluorescein isothiocyanate (FITC) and Texas Red. High resolution images were obtained showing that pinealocytes have 1-3 processes that extend primarily to other pinealocytes or presumptive pinealocytes. Pinealocytes are located within the deep pineal gland as well as adjacent to the posterior aspect of the medial habenular nuclei. Pinealocyte processes were not seen extending into the habenular nuclei, but rather ended within the deep pineal gland a significant distance from their perikarya. The TH-immunopositive fibers were distributed throughout the deep pineal gland, often forming "baskets" of fibers around pinealocytes rather than being associated primarily with blood vessels. Other uses of the confocal microscope are demonstrated on rat neural tissue reacted with peroxidase/diaminobenzidine (DAB) immunohistochemistry and FITC fluorescence immunohistochemistry (paraventricular nucleus) as well as Golgi-stained neuronal tissue (cerebral cortex). The HRP/DAB and Golgi-stained images were visualized using the reflected image mode of the confocal system.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lymphopoiesis in the chicken pineal gland

Pineal lymphoid development was studied in two breeds of chickens from hatching until sexual maturity. No lymphocytes were found in the pineal prior to 9 days of age (da). Lymphocytes migrate through the endothelium of venules into the pineal stroma. Lymphoid tissue reached its maximal accumulation in 32-da pineal glands of both breeds. At this age, the New Hampshire (NH) breed had a larger proportion of lymphoid volume to total pineal volume (32%) than did pineal glands from White Leghorn (WL) chickens (18%). Averaged over the period 23 to 62 da, NH chickens (a heavy breed) had a lymphoid volume (0.753 mm³) that was about three times greater (P < 0.05) than that of the lighter WL breed (0.251 mm³). Lymphocytes are able to enter cerebrospinal fluid from lymphoid accumulations (LA) embedded in the choroid plexus by migrating between choroid ependymal cells. The 122-da chickens typically lacked lymphoid tissue in the pineal gland with the exception of occasional LA contained in capsular tissue. Surgical bursectomy, thymectomy, or their combination at hatching followed with whole-body irradiation (IR) at 24 hours postsurgery inhibited the initial influx of lymphocytes usually seen in 9-da pineal glands. Also, these treatments prevented formation of germinal centers normally found in the pineal at 3 and 5 weeks and reduced total pineal volume at each age examined. However, pineal lymphoid volume of the surgical-IR group did not differ from control-IR chickens at either 3 or 5 weeks. Pineal glands from birds made agammaglobulinemic (bursa-cell depleted) by cyclophosphamide treatment in ovo were devoid of germinal centers, although thin strands of lymphocytes were usually found along venous sinuses. These dissociation studies suggest that the normal expression of lymphoid tissue in the chicken pineal gland is dependent on the bursa and thymus. Furthermore, these observations indicate that the pineal gland should be considered a functional component of the chicken's lymphomyeloid complex.     

Melatonin reduces noradrenaline-induced vasoconstriction in the uterine artery of pregnant hooded seals (Cystophora cristata)

In pregnant seals the dive-associated constriction of the uterine artery is inhibited for unknown reasons. The seal fetus has an extremely large and active pineal gland, not found in any other mammals. We have investigated if the pineal hormone melatonin affects fetal blood supply during diving. Using isolated ring segments of the uterine artery from pregnant hooded seals (Cystophora cristata), we measured the change in isometric tension caused by noradrenaline (NA) with and without physiological concentrations of melatonin. Melatonin alone had no effects while NA increased the tension in a dose-dependent manner. The NA-induced tension was about 70% reduced by melatonin, but was completely recovered after washout of melatonin. These results indicate that the large and active pineal gland of the fetal seal may be involved in upholding maternal uterine blood flow during diving.     

Evidence of a role for melatonin in fetal sheep physiology: direct actions of melatonin on fetal cerebral artery, brown adipose tissue and adrenal gland

Although the fetal pineal gland does not secrete melatonin, the fetus is exposed to melatonin of maternal origin. In the non-human primate fetus, melatonin acts as a trophic hormone for the adrenal gland, stimulating growth while restraining cortisol production. This latter physiological activity led us to hypothesize that melatonin may influence some fetal functions critical for neonatal adaptation to extrauterine life. To test this hypothesis we explored (i) the presence of G-protein-coupled melatonin binding sites and (ii) the direct modulatory effects of melatonin on noradrenaline (norepinephrine)-induced middle cerebral artery (MCA) contraction, brown adipose tissue (BAT) lypolysis and ACTH-induced adrenal cortisol production in fetal sheep. We found that melatonin directly inhibits the response to noradrenaline in the MCA and BAT, and also inhibits the response to ACTH in the adrenal gland. Melatonin inhibition was reversed by the melatonin antagonist luzindole only in the fetal adrenal. MCA, BAT and adrenal tissue displayed specific high-affinity melatonin binding sites coupled to G-protein ( K _d values: MCA 64 ± 1 p m , BAT 98.44 ± 2.12 p m and adrenal 4.123 ± 3.22 p m ). Melatonin binding was displaced by luzindole only in the adrenal gland, supporting the idea that action in the MCA and BAT is mediated by different melatonin receptors. These direct inhibitory responses to melatonin support a role for melatonin in fetal physiology, which we propose prevents major contraction of cerebral vessels, restrains cortisol release and restricts BAT lypolysis during fetal life.     

P-450c17mRNA在原发性醛固酮增多症肾上腺皮质腺瘤及增生组织中的表达及意义

为探讨细胞色素P-450 c17 -羟化酶(P-450 c17 )mRNA 在原发性醛固酮增多症(原醛)肾上腺皮质腺瘤（APA）及增生组织中的表达及其意义，采用 Northern Blot 法对7 例APA 组织，3 例结节样增生组织，7 例正常肾上腺组织，1 例腹壁骨骼肌组织P-450 c17 mRNA 的表达水平进行检测。结果显示P-450 c17 mRNA 在原醛APA组织与正常肾上腺组织中的表达有显著性差异P<0.05。P-450 c17 mRNA 在原醛肾上腺皮质增生组织与正常肾上腺组织中的表达、在原醛APA 组织与原醛肾上腺皮质增生组织中的表达相似。提示P-450 c17 mRNA 在APA 组织中的表达降低很可能是原醛APA 组织分泌过多醛固酮(ALD)的分子生物学原因。     

Vascularization of the pineal complex in the lizard Tiliqua rugosa

The vascularization of the pineal complex in the lizard Tiliqua rugosa was investigated by vascular corrosion and latex casting techniques. The fine structure of the pineal capillaries was also studied by transmission electron microscopy. The pineal complex in T. rugosa consists of an elongated pineal gland proper and a separate, distinct parietal eye. The pineal complex derives an abundant blood supply from branches of the middle and posterior cerebral arteries. Scanning electron microscopy of vascular corrosion casts revealed a dense and extensive pineal capillary bed which drains ultimately into a wide longitudinal sinus suggesting an efficient pathway for the rapid removal of substances secreted by the gland. The parietal eye, which receives a unilateral left-sided blood supply from the unpaired anterior pineal artery, is shown to be a highly vascularized structure. The close morphological relationship between the pineal gland and dorsal sac, where the two structures apparently share the same blood vessels, suggests a functional relationship between them. The pineal capillaries are fenestrated with tight junctions between adjoining endothelial cells. Podia-like abluminal extensions of the endothelial cells were observed in close relation to unmyelinated nerve bundles. The basal margin of the pineal parenchyma is highly invaginated with thin finger-like cytoplasmic protrusions into the pericapillary space. Distinct bands of microfibrils form “struts” anchoring the pineal parenchyma to the endothelial wall. These features may have a role in the transfer of materials between the pineal gland and the blood stream. © 1993 Wiley-Liss, Inc.     

In vivo observation of a non-noradrenergic regulation of arylalkylamine N-acetyltransferase gene expression in the rat pineal complex

The rodent pineal gland is the end point of several peripheral and central fibers innervating the superficial and deep parts of the gland. Up to now, only the sympathetic transmitter norepinephrine is thought to regulate melatonin synthesis, although numerous biochemical experiments have reported in vitro effects of various transmitters on melatonin synthesis. To find out whether there is non-noradrenergic regulation of in vivo pineal metabolism, the mRNA encoding the enzyme arylalkylamine N-acetyltransferase was studied using the highly sensitive technique of in situ hybridization. The existence of a marked nocturnal increase of arylalkylamine N-acetyltransferase mRNA in the superficial pineal gland was confirmed. Interestingly and for the first time, a similar daily variation was observed in the deep pineal. After removal of superior cervical ganglia, the daily rhythm in arylalkylamine N-acetyltransferase mRNA was abolished in both the superficial and deep pineal indicating that the rhythm is driven by sympathetic input in the entire pineal complex. Interestingly, the remaining arylalkylamine N-acetyltransferase mRNA level in the pineal of day- and night-time ganglionectomized rats was significantly higher than in the pineal of day-time intact animals. These data reveal a sympathetic-dependent day-time inhibition of arylalkylamine N-acetyltransferase gene expression. In addition, the day-time pineal arylalkylamine N-acetyltransferase mRNA expression in ganglionectomized rats persisted after adrenal gland removal but was reduced by 50% after propranolol injection. These results indicate that arylalkylamine N-acetyltransferase mRNA in ganglionectomized rats is not induced by circulating catecholamines and may be caused by both a centrally originated norepinephrine, as already suggested, and other non-adrenergic transmitter(s). In conclusion, this work shows that norepinephrine drives the nocturnal increase of arylalkylamine N-acetyltransferase gene expression both in the superficial and deep pineal and strongly suggests that other neurotransmitters are involved in day-time inhibition and night-time stimulation of pineal metabolism.     

Effect of stress and dexamethasone on immunoreactive β-endorphin levels in rat hypothalamus and pineal

In response to mild stress the levels of immunoreactive β-endorphin in rat anterior pituitary, hypothalamus and pineal fell within 10 minutes from 210 to 129 pmol/lobe, 1.47 to 0.89 pmol/mg protein and 2.53 to 0.41 pmol/gland, respectively. No alterations were found to take place in β-endorphin levels in posterior pituitary or plasma. Dexamethasone pre-treatment given 18 h prior to stress resulted in significantly greater reduction of β-endorphin levels in hypothalamus and pineal than stress alone—hypothalamic levels fell to 0.73 pmol/mg protein and pineal to 0.07 pmol/gland. Plasma β-endorphin levels in dexamethasone pretreated stressed rats were significantly lower than in intact rats (42 fmol/ml vs. 98 fmol/ml). The almost complete disappearance of β-endorphin from the pineal in response to stress and dexamethasone suggests that pineal does not itself synthesize the hormone but only utilizes and/or stores it. Gel filtration analysis of the β-endorphin im-munoreactivity in tissue extracts and plasma showed that anterior pituitary and plasma contain three immunoreactive components, eluting like β-endorphin,βP-Epotropin and pro-opiocortin, whereas only β-endorphin-like material was detected in posterior pituitary, hypothalamus and pineal.     

Nervous control of the adrenal cortex

Summary Rabbits were used to study the effect on function of denervating the adrenal gland. The amount of ascorbic acid in the gland served as an index. Twenty to sixty-five days after the splanchnic nerve had been divided, the semilunar ganglion and the two superior ganglia of the addominal sympathetic chain excised, and the nerve fibers running to the adrenal gland along the blood vessels divided, the ascorbic acid content of the adrenal gland fell. The decrease was most marked between the 20th and 36th days. It is suggested that the CNS exterts a trophic effect on the adrenal cortex.(Presented by Active Member AMN SSSR A. B. Lebedinskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 51, No. 6, pp. 24–28, June, 1961.     

Cytologic features of the normal pineal gland on squash preparations

As primary pineal lesions are extremely rare, many surgical pathologists are unfamiliar with normal pineal cytologic features. We describe cytologic features of the normal pineal gland in patients of varying ages and identify common diagnostic pitfalls. We performed a retrospective review of pineal gland biopsies performed at our institution, where approximately 30,000 surgical specimens are accessioned yearly, for the last 23 years. Only two pineal gland biopsies were found. Although both cases were initially diagnosed as low‐grade gliomas on frozen section, the final diagnosis was benign pineal tissue based on light microscopy and immunohistochemistry results. Additionally, we performed squash preparations of five normal pineal gland autopsy specimens with Papanicolaou and Diff–Quik® (Dade Behring, Newark, DE) stains. Infant preparations were highly cellular smears composed of numerous, uniform, single cells with indistinct cytoplasm, small round‐to‐oval nuclei, fine chromatin, and absent nucleoli and calcifications. The vague microfollicular pattern mimicked a pineocytoma and the fine fibrillary background mimicked a glial neoplasm. Young adult smears were similar; however, microcalcifications were present with fewer background single cells. Older patients had much less cellular smears composed of small clusters of cells with fusiform‐to‐spindle nuclei, a fine chromatin pattern, and indistinct cytoplasmic borders. There were fewer background single cells and more microcalcifications. The cytologic features of the native pineal gland vary with age. Normal pineal tissue can be confused with a pineocytoma or low‐grade glioma. Familiarity with normal pineal gland cytological features will help to avoid a potential misdiagnosis. Diagn. Cytopathol. 2014;42:939–943. © 2014 Wiley Periodicals, Inc.     

Pineal influence on intermale aggression in adult house mice.

Previously isolated, adult male mice of a wild-derived strain were sham-operated or pinealectomized (pinx) and 14 days later were paired for 15 min, then grouped three per cage for 7 days. During 15 min pairings, mean latency to initiation of fighting was increased twofold and duration of fighting was reduced 35 to 41 percent in pairs comprised of one or both pinx animals. Although pinealectomy failed to influence which pair member initiated fighting, sham males were ranked as dominant in 75 percent of sham-pinx pairs. Pinealectomy reduced adrenal gland weights among isolated animals and increased in general the effects of social subordination in grouped males. Compared to sham subordinates, pinx subordinates experienced adrenal enlargment and twofold greater wounding and had lighter thymus glands and final body weights. Additionally, however, pinealectomy prevented atrophy of seminal vesicles among subordinates. Thus, present results suggest a role of the pineal gland in influencing intermale aggression and linking social stimuli with testis dysfunction in adult house mice.     

The mechanisms of stress and immunosuppression

The effects of stress on the central nervous system, endocrine balance, and immunity were observed in male Sprague-Dawley rats. Food and water were supplied in unlimited quantities. Extraneous odors were kept away from the control room by an exhaust fan in the adjacent room. At 70 days, experimentation occurred for 20 days.In the aspirin, parathroid, serotonin, and pineal groups, there was no significant difference between the undisturbed control and experimental groups. A significant reduction in both the pituitary and adrenal weights was seen in the melatonin experimental group and the undisturbed control group. The placebo control group showed a significant increase in both the pituitary and adrenal gland weights.Stress was blocked in the groups receiving aspirin, parathroid, serotonin, and pineal preparations. The melatonin group, however, very significantly blocked the stress in that both the pituitary and adrenal weights were significantly below the undisturbed control group. The aspirin blocked stress by inhibiting synthesis of prostaglandins. Melatonin works through the pituitary — adrenal axis to reduce adrenal secretion.     

Immunobiological changes of in vivo glucocorticoid depleted male Swiss albino rats

Whether endogenous deficiency of adrenal corticosteroid by unilateral adrenalectomy leads to any modulation of macrophage response is not clear and needs investigation in detail. We performed unilateral adrenalectomy on male Swiss albino rats. Fractions of splenic macrophages were isolated and their functional activities were determined. To test the effect of adrenal hormone insufficiency (after unilateral adrenalectomy) on the cell mediated and humoral immune response, sheep red blood cells were injected, then the delayed type hypersensitivity (DTH) response and the number of antibody secreting plasma cells were determined. Studies reported herein indicate that in vivo glucocorticoid (GC) insufficiency due to unilateral adrenalectomy decreases chemotactic migration, myeloperoxidase enzyme release, and lysozyme release from rat splenic macrophages that were also related to the induction of cell mediated and humoral immune responses. The maximum number of plaque was obtained from control cells isolated from spleen after 10 days from the control rats, whereas the number of plaque was decreased in spleens isolated 20 days after unilateral adrenalectomy. Our study also showed time dependent decrease in foot pad swelling in the unilaterally adrenalectomized rats where endogenous GC was reduced with respect to control indicating reduced DTH response in case of GC insufficiency. We found slower clearance of bacterial burden from the blood and spleen isolated from unilaterally adrenalectomized rats with respect to control. Thus on one hand partially GC insufficient animals show altered macrophage response and on the other hand it heightens the persistence (in vivo) of Staphylococus aureus. The study may be helpful in understanding that adrenal corticosteroid insufficiency due to adrenalectomy interferes with immune functions, which may also support the hypothesis that endogenous GC plays a role in regulating immune response.     

Effect of insulin on serotonin, 5-hydroxyindole-acetic acid, norepinephrine, epinephrine and corticosterone contents in chick.

Pineal serotonin (5-HT), 5-hydroxyindole-acetic acid (5-HIAA), norepinephrine (NE), epinephrine (E) and adrenal corticosterone, NE and E contents were measured spectrofluorometrically 5, 15, 30 and 60 min after insulin treatment to induce hypoglycemic stress. In the pineal gland, hypoglycemic stress caused dramatic decrease of 5-HT, resulted in initial decrease followed by an increase of 5-HIAA and brought about changes of NE and E. Corticosterone content in the adrenal gland increased significantly following treatment with insulin. Adrenal NE and E contents plummetted to control value followed by quick resynthesis. The findings indicate that insulin-induced hypoglycemia greatly modulates the activities of pineal and adrenal glands.     

Histophysiological evidence for the secretion of polypeptides by the pineal gland

Histophysiological examinations of the bovine and monkey pineal gland indicate that this organ may be involved in the secretion of polypeptides. Using various histochemical procedures designed to identify peptidesecreting cells, granules and/or droplets of presumptive secretory product were identified within cellular processes, within the walls of blood vessels and associated with multilayered corpuscles (corpora arenacea). In bovine pineal tissue, the stained material was found most often in what appeared to be pinealocyte processes, as perivascular granules and associated with multilayered corpuscles. In the monkey pineal the stainable material was more distinct; this was probably due to the earlier fixation of the glands after death of the animals. In this species, the presumptive secretory material was found in nerve fibers, occasionally in glial cell and pinealocyte processes and within and around the walls of capillaries. In nerve fibers, the stained material sometimes resembled Herring bodies of the posterior pituitary gland. Similar material appeared to be located in capillary endothelial cells and within multilayered corpuscles. In pineal tissue of both species, calcium was detectable histochemically within multilayered corpuscles. Although tinctorially different, the presumptive neurosecretory material was similar to that found in the posterior pituitary gland. As a working hypothesis, we propose that polypeptides may be released from cells in conjunction with a carrier protein and that the mechanism of secretion of the polypeptide into the vascular system may involve its exchange for calcium. The calcium is then theoretically deposited in the multilayered corpuscles.     

Quantitative estimation of 17alpha-hydroxypregn-4-ene-3,20-dione (17alphaOH-progesterone) in adrenal venous blood and adrenal glands

1. A method is described for the accurate estimation of small quantities of 17α-hydroxypregn-4-ene-3,20-dione (17αOH-progesterone) in blood and adrenal glands.

2. The dog adrenal was found to secrete 17αOH-progesterone under conditions of operative stress at a rate of 5-10 μg/g tissue/hr. This is similar to the secretion rate of aldosterone.

3. The secretion of 17αOH-progesterone was decreased after hypophysectomy and increased in response to adrenocorticotrophic hormone (ACTH).

4. The adrenal gland of the dog, the monkey and the guinea-pig was found to contain between 0·6 and 6 μg of 17αOH-progesterone/g tissue. The concentration was usually somewhat smaller than that of pregnenolone or progesterone and between 1 and 20% of the concentrations of the glucocorticoids.

5. A comparison of adrenal steroid contents and secretion rates under conditions of stress indicates a rate of synthesis in the order of 30-40 n-moles of 17αOH-progesterone/g adrenal tissue/min.