Journal of Endocrinology and Reproduction

Sunanda Dubey ¹, Rakesh Verma ¹, Shraddha Rastogi ², Chandana Haldar ²

Affiliations
1 Department of Zoology, Udai Pratap Autonomous Degree College, Bhojubir, Varanasi-221002, IN
2 Pineal Research Laboratory, Department of Zoology, Banaras Hindu University, Varanasi - 221005, IN

Abstract

Mostly studied in the hamster, the Harderian gland (HG, an extra-orbital gland) has been shown to be capable of melatonin (MEL) synthesis and to possess steroid receptor binding sites. Sexual dimorphism and ability to respond to steroid hormones have been reported for HG of some temperate zone mammals. However, to date there is no report on functional relation of HG with pineal, pituitary and gonad in any rodent. Hence, we tested the effect of gonadotropins [FSH (10μg) + LH (10μg)] and steroids [testosterone (100μg) and 17-β estradiol (50μg)] on HG function in relation to the activities of the pineal gland and gonad in both sexes of Indian palm squirrel Funambulus pennanti during the sexually quiescent phase. In general, squirrels treated with gonadotropins and gonadal steroids showed a significant increase in gonadal weight and decrease in pineal weight and plasma melatonin level in LH- and testosterone-treated groups only. There was no change in the weight of HG on FSH treatment. Porphyrin content of HG decreased after testosterone and estradiol treatment. Pineal gland weight invariably decreased after treatment with gonadotropins and testosterone. Plasma testosterone and estradiol levels increased but melatonin level decreased in all treated groups. Our data suggest that in this tropical rodent gonadotropins have an indirect effect on HG and that gonadal steroids have significant effect on HG through the influence on gonadal and pineal functions.

Keywords

Gonadotropins, Harderian Gland, Melatonin, Pineal, Rodent.

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Sunanda Dubey ¹, Rakesh Verma ², Chandana Haldar ²

Affiliations
1 Department of Zoology, Udai Pratap Autonomous Degree College, Bhojubir, Varanasi-221002, IN
2 Pineal Research Laboratory, Department of Zoology, Banaras Hindu University, Varanasi-221005, IN

Abstract

The structure of Harderian gland (HG) of tropical avian species has never been studied in detail. In the present study we investigated the structure of HG of a t ropical avian species adopting light- and transmission electron microscopy. HG from both male and female adult birds, P. asiatica (N=5 each sex) were studied from light microscopic (hematoxylin-eosin staining) and transmission electron microscopic perspectives. The tubulo-alveolar HG of P. asiatica did not reveal any sexual dimorphism as reported in other birds. The HG of this bird is encapsulated by thick connective tissue consisting of collagen fibers, nerve fibers and blood vessels. HG lobules are lined with columnar epithelial cells. Plasma cells are found in interlobular spaces. The columnar epithelial cells are secretory in nature and have both rough and smooth endoplasmic reticula surrounding the nucleus when observed in transmission electron microscope. There is active Golgi apparatus with dilated cisternae. Mitochondria are well developed, with elongated cristae, and are scattered throughout the cytoplasm along with abundant free ribosomes. Lipid droplets are present in the cytoplasm along with two types of materials, electron-luscent and electron-dense. We could trace the various stages of synthesis of the secretory material for merocrine release. Thus, the light microscopic and ultrastructural organization of HG of P. asiatica have been elucidated.

Keywords

Bird, Indian Jungle Bush Quail, Harderian Gland, Secretory Acini.

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