Inhibitory Effects of a Pineal Extract on Adrenal Cortex Lack of Competition with ACTH

Heiman, Mark L.; Porter, Johnny R.

doi:10.1159/000179110

Cited by 20 publications

(6 citation statements)

References 12 publications

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“…Probably, this is closely related to the variations that were found in the activity of the pineal gland of this rodent throughout the year (6). Its action on glomerulosa (25), fasciculata (26) and reticularis zones has been described by other authors. In addition, the results of the reproductive study matched those obtained for the inhibitory action of the pineal on both the pituitary-gonadal and the pituitary-adrenal systems.…”

Section: Discussionsupporting

confidence: 65%

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

Ribes

Mohamed

Domínguez

et al. 1999

Braz J Med Biol Res

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The neuroendocrine system regulates several organic functions such as reproduction, metabolism and adaptation to the environment. This system shows seasonal changes linked to the environment. The experimental model used in the present study was Lagostomus maximus maximus (viscacha). The reproduction of males of this species is photoperiod dependent. Twenty-four adult male viscachas were captured in their habitat at different times during one year. The adrenal glands were processed for light microscopy. Serial cuts were stained with hematoxylin-eosin for the morphometric study, and 100 nuclei of each zone of the adrenal cortex were counted per animal. Data were analyzed statistically by ANOVA and the Tukey test. The cells of the glomerulosa zone are arranged in a tube-shaped structure. The fasciculata zone has large cells with central nuclei and clearly visible nucleoli and with a vacuolar cytoplasm. In the reticularis zone there are two of types of cells, one with a nucleus of fine chromatin and a clearly visible nucleolus and the other with nuclear pycnosis. Morphometric analysis showed maximum nuclear volumes during the FebruaryMarch period with values of 133 ± 7.3 µm 3 for the glomerulosa, 286.4 ± 14.72 µm 3 for the fasciculata, and 126.3 ± 9.49 µm 3 for the reticularis. Minimum nuclear volumes were observed in August with values of 88.24 ± 9.9 µm 3 for the glomerulosa, 163.7 ± 7.78 µm 3 for the fasciculata and 64.58 ± 4.53 µm 3 for the reticularis. The short winter photoperiod to which viscacha is subjected could inhibit the adrenal cortex through a melatonin increase which reduces the nuclear volume as well as the cellular activity.

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Section: Discussionsupporting

confidence: 65%

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

Ribes

Mohamed

Domínguez

et al. 1999

Braz J Med Biol Res

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“…Pinealectomy promoted an impressive 2-fold increase in plasma corticosterone levels at all times investigated. Classical studies have shown that melatonin and pinealectomy have a modulatory effect on rat adrenal glands [11,24,25]. In addition, a recent study demonstrated the presence of melatonin receptors in primate adrenals, which inhibited ACTH-stimulated cortisol production [14].…”

Section: Discussionmentioning

confidence: 99%

Light/Dark Cycle-dependent Metabolic Changes in Adipose Tissue of Pinealectomized Rats

et al. 2004

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We investigated the effects of pinealectomy on adipose tissue metabolism at different times of day. Adult male Wistar rats were divided into two groups: pinealectomized and control (sham-operated). Eight weeks after surgery, the animals were killed at three different times (at 8.00 a.m., at 4.00 p.m. and 11.00 p.m.). We collected blood samples for glucose, insulin, corticosterone, and leptin determinations, and periepididymal adipocytes for in vitro insulin-stimulated glucose uptake, oxidation, and incorporation into lipids. Pinealectomy caused insulin resistance as measured by 2-deoxyglucose uptake (a fall of approximately 40 % in the maximally insulin-stimulated rates) accompanied by hypercorticosteronemia at the three time points investigated without changes in plasma insulin an or leptin levels. Furthermore, pinealectomy increased the insulin-induced glucose incorporation into lipids (77 %) at 4.00 p.m. and insulin-induced glucose oxidation in the morning and in the afternoon, while higher rates were observed in the evening and in the morning in control rats. In conclusion, cell responsiveness to insulin was differentially affected by pineal ablation and time of day, and persistent insulin resistance was obtained in pinealectomized rats. We hypothesize that pinealectomy exposes the animal to an inadequate match between energy requirements and fuel mobilization.

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“…To what extent (if at all) phenomena such as induction, repression, transcription, and translation of gene expression are involved can then be studied at critical times in the feed-sideward. In any event, if the feed-sideward switches the biogenesis of adrenocortical hormones from the path leading to aldosterone or cortisol to that leading to dehydroepiandrosterone, it could account for the fact that both stimulation and inhibition have been reported for pineal effects upon aldosterone production (Farrell, 1959;Fabre et al, 1965) as well as for corticosterone responses (Porter and Heiman, 1977;Heiman and Porter, 1980;Porter, personal communication). Yet more important is the possibility that one may switch competing risks and perhaps one day manipulate such risks to optimize them.…”

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confidence: 99%

Quo vadis basic and clinical chronobiology: Promise for health maintenance

Halberg

1983

Am. J. Anat.

127

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Chronobiology is the eminently interdisciplinary science of interactions in time among metabolic, hormonal, and neuronal networks. It involves anatomy, biochemistry, microbiology, physiology, and pharmacology, at the molecular, intracellular, intercellular, and still higher levels of organization. The compounds coordinating a time structure--proteins, steroids, and amino-acid derivatives--provide for the scheduling of interactions among membrane, cytoplasmic, and nuclear events in a network involving rhythmic enzyme reactions and other intracellular mechanisms. The integrated temporal features of the processes of induction, repression, transcription, and translation of gene expression remain to be mapped in relation to the available framework, consisting of the sequences of phospholipid and RNA labeling, DNA formation, and mitosis, to delineate a circadian cell cycle upon which further hormonal and neural coordination acts (Halberg et al., 1959a,b, 1979a). There is a need for communication over temporal as well as spatial distances among different specialized structures devoted, in individuals, to metabolism, growth, reproduction, and the ability to adjust, and, in species, to the capacity to adapt. For a better understanding at all levels of behavior in its broader sense of organization in time, chronobiology requires familiarity with temporal aspects of metabolism, hormones, and neurons. In other words, broadly trained, full-time "general practitioners" of a chronobiology in its own right are needed.

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Inhibitory Effects of a Pineal Extract on Adrenal Cortex Lack of Competition with ACTH

Cited by 20 publications

References 12 publications

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

Light/Dark Cycle-dependent Metabolic Changes in Adipose Tissue of Pinealectomized Rats

Quo vadis basic and clinical chronobiology: Promise for health maintenance

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