Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13, 10-719 Olsztyn, Poland.
Molecules. 2021 Oct 20;26(21):6329. doi: 10.3390/molecules26216329.
The embryonic ontogeny of pineal secretory activity in birds has been investigated almost exclusively in chickens. This study aimed to characterize this process in domestic geese. The pineal organs of embryos aged 18-28 days were incubated in superfusion culture under different light conditions for 4-5 days and treated with norepinephrine (NE). Melatonin (MLT) was measured by radioimmunoassay and other indoles by HPLC with fluorescence detection. Additionally, pineal organs were collected from embryos at 14-28 days of age and used to measure catecholamines by HPLC with electrochemical detection. MLT secretion increased with embryo age, most intensively between the 22nd and 24th days of life. The daily changes in MLT secretion under the 12 L:12D cycle occurred on the first day of culture, starting from an embryonic age of 24 days. MLT secretion was controlled by the light-dark cycle in all age groups studied. However, exposure to light during the scotophase did not alter the secretion of MLT. The endogenous oscillator expressed its activity in regulating MLT secretion in the pineal organs of embryos aged 24 days and older but could not generate a rhythm after one cycle. The rhythm of 5-hydroxytryptophan release during the first day of culture was found in the pineal organs of all embryos, while the rhythmic release of -acetylserotonin and 5-methoxyindole acetic acid started at the age of 24 days. The proportion of released indoles changed with embryo age. NE caused a decrease in MLT secretion and provoked an increase in serotonin release. Incubation of the pineal organs induced the development of MLT secretory machinery and its diurnal rhythmicity. The pineal content of catecholamines increased prominently at the end of embryonic development.
鸟类松果腺分泌活动的胚胎发生过程在很大程度上仅在鸡中进行了研究。本研究旨在表征家鹅中的这一过程。将 18-28 日龄胚胎的松果腺在不同光照条件下于灌注培养中孵育 4-5 天，并加入去甲肾上腺素（NE）。通过放射免疫测定法测量褪黑素（MLT），并通过 HPLC 与荧光检测测量其他吲哚。此外，从 14-28 日龄的胚胎中收集松果腺，并用 HPLC 与电化学检测测量儿茶酚胺。MLT 分泌随胚胎龄增加而增加，在生命的第 22-24 天之间最为强烈。在 12L:12D 周期下，MLT 分泌的日变化发生在培养的第一天，从胚胎龄 24 天开始。在所有研究的年龄组中，MLT 分泌均受光暗周期控制。然而，在暗期暴露于光线下不会改变 MLT 的分泌。内源性振荡器在调节 24 日龄及以上胚胎松果腺中 MLT 分泌方面发挥作用，但在一个周期后无法产生节律。在培养的第一天发现所有胚胎的松果腺中都有 5-羟色氨酸释放的节律，而 -乙酰血清素和 5-甲氧基吲哚乙酸的节律性释放则始于 24 日龄。释放的吲哚比例随胚胎龄而变化。NE 导致 MLT 分泌减少并引起血清素释放增加。松果腺器官的孵育诱导 MLT 分泌机制及其昼夜节律的发育。在胚胎发育末期，松果腺中的儿茶酚胺含量显著增加。
