Abstract.To investigate the effect of hypothyroidism on gonadal and adrenal functions in male Japanese quail (Coturnix japonica), hypothyroidism was induced in male adult Japanese quail by daily administration of 2-Mercapto-1-methylimidazole (methimazole) in their drinking water. Four weeks after methimazole treatment, the Japanese quail were scarificed, and the plasma concentrations of free triiodothyronine (FT3), free thyroxine (FT4), total T3 (TT3), total T4 (TT4), corticosterone, testosterone, LH and immunoreactive (ir) inhibins were measured by radioimmunoassy, the testes and adrenal glands were removed and weighed and the thyroid glands and testes were fixed in 4% paraformaldehyde for histological observation. The results showed that the hypothyroidism induced by methimazole caused a significant decrease in body and testes weight; the plasma levels of FT3, FT4 and TT4 significantly decreased, and the hypothyroid quail possessed a greater number of small follicles and more follicular epithelial cells in the thyroid gland. In addition, hypothyroidism resulted in a significant decrease in the plasma concentrations of corticosterone, LH, testosterone and irinhibin. Furthermore, no spermatogenesis was found in the seminiferous tubules of the methimazole treatment groups. These results clearly demonstrate that hypothyroidism caused both gonadal and adrenal disturbances in the adult male Japanese quail.
Abstract. The objective of this study was to investigate the changes in secretion of inhibin and cellular localization of the inhibin α and inhibin/activin (βA and βB) subunits in male Japanese quail from 1 to 7 weeks after hatching. The posthatch profile of plasma luteinizing hormone (LH), immunoreactive (ir) inhibin and testosterone were measured by radioimmunoassay. Testes were immunostained by the avidin-biotin-peroxidase complex method (ABC) using polyclonal antisera raised against inhibin α, inhibin/activin βA and inhibin/activin βB from one week of age to sexual maturity. Testicular weight increased gradually until 4 weeks and abruptly increased from 5 weeks of age onwards. The plasma concentrations of LH and ir-inhibin increased significantly at 5 weeks of age, and the plasma concentration of testosterone increased significantly at 6 weeks of age. Pituitary contents of LH showed a steady increase until 6 weeks of age and then abruptly increased at 7 weeks of age. Coincident to the increase in plasma testosterone, the testicular contents of testosterone significantly increased from 5 weeks through sexual maturity.Immunohistochemically, localization of the inhibin/activin α, βA and βB subunts was found in the Sertoli and Leydig cells at all ages of development from one week of age to sexual maturity. These results suggest that Sertoli and Leydig cells are the major source of inhibin secretion during development in male Japanese quail. Key words: Inhibin, Japanese quail (Coturnix japonica), Luteinizing hormone (LH), Testes, Testosterone (J. Reprod. Dev. 54: [100][101][102][103][104][105][106] 2008) nhibins and activins are growth and differentiation factors that have been localized in both the reproductive and non-reproductive organs. They exert their effects through both endocrine and local (autocrine/paracrine) mechanisms [1]. Inhibins and activins are structurally related dimeric gonadal proteins with the ability to regulate follicle-stimulating hormone (FSH) secretion from the pituitary glands [2,3]. Inhibin consists of an α subunit linked by a disulfide bridge to one of the 2 highly homologous β subunits (βA and βB) to form inhibin A (α and βA) or inhibin B (α and βB) [4]. In mammalian species, apart from their action on FSH secretion, the inhibins and activins have been shown to exert paracrine/autocrine effects within the gonads [5][6][7][8] and other tissues [9] and have been proposed to have an important paracrine function during testes development [10,11]. In the male, inhibin is produced in the testis, principally by Sertoli cells. There are temporal changes in inhibin expression and secretion with the changing role of the Sertoli cell in immature and adult testes. Variations in inhibins production among species reflect the different patterns of maturation [11][12][13].In avian species, studies have confirmed a mammalian-type endocrine role for inhibins [14][15][16][17]; however, the autocrine/paracrine roles of inhibins and activins in the gonads are still being defined. The profiles of plasm...
Abstract.To clarify the cellular source and secretory pattern of inhibin in the Japanese quail during follicular development, the plasma concentrations of immunoreactive (ir) inhibin were measured from 1 to 7 weeks after hatching. Localization of the inhibin/activin α, βA and βB subunts was investigated by immunohistochemistry. To monitor development of the pituitary and ovarian functions, the plasma luteinizing hormone (LH) and progesterone concentrations were also measured. Ovarian weight increased gradually until 6 weeks of age and then abruptly increased at 7 weeks of age just at the onset of egg production. Plasma concentrations of LH increased significantly at 6 weeks of age. The plasma concentrations of ir-inhibin and progesterone and the pituitary contents of LH also increased significantly at 7 weeks of age. Immunohistochemically, the inhibin/activin α, βA and βB subunts were localized in the granulosa cells of all follicles during different stages of development from 1 to 7 weeks after hatching. The inhibin α, βA and βB subunts were also found in the interstitial cells but not theca cells of all follicles. These results demonstrated that the plasma concentrations of ir-inhibin of the female Japanese quails rose with ovarian development. The immunohistochemical results suggested that granulosa and interstitial cells are the major source of ovarian inhibins in female Japanese quails. Key words: Development, Female quail, Inhibin, Luteinizing hormone (LH), Progesterone (J. Reprod. Dev. 54: [52][53][54][55][56][57] 2008) nhibins and activins are structurally related dimeric gonadal proteins with the ability to regulate follicle-stimulating hormone (FSH) secretion from pituitary glands in mammals [1,2]. Inhibin consists of an α subunit linked by a disulfide bridge to one of the 2 highly homologous β subunits (βA and βB) to form inhibin A (α and βA) or inhibin B (α and βB) [3]. Apart from their action on FSH secretion, inhibins and activins have been shown to exert paracrine/autocrine effects within the gonads [4,5] and other tissues [6]. In mammalian females, the roles played by inhibin/ activin in modulating FSH secretion by the pituitary gland in vivo and in vitro have been well documented. Inhibins selectively suppress [7-12] while activins stimulate [11][12][13][14][15] the release of FSH. Previous studies have shown that the avian ovary also produces inhibins, which plays important roles in the regulation of pituitary FSH [16][17][18][19][20][21]. However, the roles of inhibins have received little attention in quail. As a laboratory animal, the female Japanese quail has been extensively used in reproductive research, because of its adaptability to battery breeding cages, small body size, early sexual maturation, short generation interval, regular egg laying and high egg production. However, studies on the reproductive endocrinology of quails are scarce. Specifically, no research results have been published concerning the secretion of inhibins in female quails. In order to clarify the possible endoc...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.