Adrenergic regulation of cytoplasmic structures related to secretory processes in pig pinealocytes—an ultrastructural, quantitative study

Przybylska‐Gornowicz, Barbara; Lewczuk, Bogdan; Ziółkowska, Natalia; Prusik, Magdalena

doi:10.1016/j.micron.2017.06.004

Cited by 1 publication

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“…The morphology and physiology of the pig pineal gland show several species-specific features concerning mechanisms of adrenergic regulation of melatonin secretion [ 36 , 37 ], daily patterns of plasma melatonin level [ 38 , 39 , 40 ], and the ultrastructure of pinealocytes [ 41 , 42 , 43 ]. In contrast to the rat pineal gland, norepinephrine stimulates melatonin synthesis in pig pinealocytes without an induction of transcription and translation of serotonin N-acetyltransferase [ 36 , 37 ], most likely by an increase in the affinity of this enzyme to serotonin [ 44 ].…”

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confidence: 99%

Effects of Streptozotocin-Induced Diabetes on the Pineal Gland in the Domestic Pig

Lewczuk

Prusik

Ziółkowska

et al. 2018

IJMS

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Several observations from experiments in rodents and human patients suggest that diabetes affects pineal gland function, including melatonin secretion; however, the accumulated data are not consistent. The aim of the present study was to determine the effects of streptozotocin-induced diabetes on the pineal gland in the domestic pig, a species widely used as a model in various biomedical studies. The study was performed on 10 juvenile pigs, which were divided into two groups: control and diabetic. Diabetes was evoked by administration of streptozotocin (150 mg/kg of body weight). After six weeks, the animals were euthanized between 12.00 and 14.00, and the pineal glands were removed and divided into two equal parts, which were used for biochemical analyses and for preparation of explants for the superfusion culture. The pineal contents (per 100 μg protein) of serotonin, 5-hydroxyindole acetic acid, 5-hydroxytryptophol, 5-methoxyindole acetic acid, 5-methoxytryptophol, and 5-methoxytryptamine were significantly lower in diabetic pigs than in control pigs. In contrast, the level of N-acetylserotonin was significantly higher in diabetic animals. No significant differences were found in the level of melatonin between control and experimental pigs. The amounts of 3,4-dihydroxyphenylalanine, dopamine, norepinephrine, and 3,4-dihydroxyphenylacetic acid were significantly lower in the pineal glands of diabetic animals. The level of vanillylmandelic acid was higher in diabetic pigs. No differences were observed in the level of basal and NE-stimulated release of N-acetylserotonin or melatonin between the pineal explants prepared from control and experimental animals. In vitro treatment with insulin was ineffective. In conclusion, streptozotocin-induced diabetes affects both indole metabolism and adrenergic neurotransmission in the pig pineal gland.

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