Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania 'Luigi Vanvitelli', Via Vivaldi, 43-81100 Caserta, Italy.
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania 'Luigi Vanvitelli', Via Vivaldi, 43-81100 Caserta, Italy.
Gen Comp Endocrinol. 2020 Oct 1;297:113548. doi: 10.1016/j.ygcen.2020.113548. Epub 2020 Jul 15.
The Harderian gland (HG) is an exocrine gland located within the eye socket in a variety of tetrapods. During the 1980s and 1990s the HG elicited great interest in the scientific community due to its morphological and functional complexity, and from a phylogenetic point of view. A comparative approach has contributed to a better understanding of its physiology. Whereas the chemical nature of its secretions (mucous, serous or lipids) varies between different groups of tetrapods, the lipids represent the more common component among different species. Indeed, besides being an accessory to lubricate the nictitating membrane, the lipids may have a pheromonal function. Porphyrins and melatonin secretion is a feature of the rodent HG. The porphyrins, being phototransducers, could modulate HG melatonin production. The melatonin synthesis suggests an involvement of the HG in the retinal-pineal axis. Finally, StAR protein and steroidogenic enzyme activities in the rat HG suggests that the gland contributes to steroid hormone synthesis. Over the past twenty years, much has become known on the hamster (Mesocricetus auratus) HG, unique among rodents in displaying a remarkable sexual dimorphism concerning the contents of porphyrins and melatonin. Mainly for this reason, the hamster HG has been used as a model to compare, under normal conditions, the physiological oxidative stress between females (strong) and males (moderate). Androgens are responsible for the sexual dimorphism in hamster and they are known to control the HG secretory activity in different species. Furthermore, HG is a target of pituitary, pineal and thyroid hormones. This review offers a comparative panorama of the endocrine activity of the HG as well as the hormonal control of its secretory activity, with a particular emphasis on the sex dimorphic aspects of the hamster HG.
哈德氏腺（HG）是一种位于各种四足动物眼眶内的外分泌腺。在 20 世纪 80 年代和 90 年代，由于其形态和功能的复杂性，以及从系统发育的角度来看，HG 引起了科学界的极大兴趣。比较方法有助于更好地了解其生理学。虽然其分泌物（粘液、浆液或脂质）的化学性质因四足动物的不同群体而异，但脂质是不同物种中更常见的成分。事实上，除了作为一种辅助性的眨眼膜润滑剂外，脂质可能具有信息素功能。卟啉和褪黑素的分泌是啮齿动物 HG 的特征。作为光传感器的卟啉可以调节 HG 褪黑素的产生。褪黑素的合成表明 HG 参与了视网膜-松果腺轴。最后，大鼠 HG 中的 StAR 蛋白和类固醇生成酶活性表明该腺参与了类固醇激素的合成。在过去的二十年中，人们对仓鼠（Mesocricetus auratus）HG 有了更多的了解，与啮齿动物不同的是，它在卟啉和褪黑素含量方面表现出显著的性别二态性。主要是由于这个原因，仓鼠 HG 被用作模型，在正常条件下比较雌性（强）和雄性（中度）之间的生理氧化应激。雄激素是仓鼠性别二态性的原因，它们被认为控制着不同物种的 HG 分泌活性。此外，HG 是垂体、松果腺和甲状腺激素的靶器官。本综述提供了 HG 内分泌活动以及其分泌活性的激素控制的比较概况，特别强调了仓鼠 HG 的性别二态性方面。
