brain-pituitary-gonadal axis in the rainbow trout, Salmo gairdneri. II. Direct effect of gonadal steroids on the gonadotropic cells

• Published in: Cell and tissue research 1983, Vol.233 (2), p.377-388
• Main Authors: Gielen, J.T, Goos, H.J.T
• Format: Article
• Language: English
• Subjects: animal anatomy; animal morphology; animal physiology; Animals; aquatic organisms; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Glycoproteins - metabolism; Gonadotropins, Pituitary - metabolism; Male; Microscopy, Electron; Non mammalian vertebrate reproduction; Pituitary Gland - physiology; Pituitary Gland - transplantation; Pituitary Gland - ultrastructure; Salmonidae - physiology; Testosterone - physiology; Trout - embryology; Trout - physiology; Vertebrates: reproduction
• ISSN: 0302-766X; 1432-0878
• DOI: 10.1007/BF00238304

In a cytophysiological study it was investigated whether in juvenile trout gonadal steroids stimulate the gonadotropic (GTH)-cells directly or indirectly via the brain. Pituitaries of donor animals were transplanted into the caudal musculature of testosterone-treated and non-testosterone-treated host fish. Testosterone treatment caused an increase in GTH-content in the in situ pituitaries and in the grafts. Accordingly, the gonadotrops displayed ultrastructural changes such as the appearance of well-developed Golgi systems and large globules. The stimulation of the morphological development of gonadotrops and of synthesis and storage of GTH in the allografted pituitaries indicates that testosterone affects the GTH-cells directly. In untreated juvenile trout the gonadotropin content of the pituitary and the gonadotropin concentration in the plasma vary with the time of year. This variation and the role of testosterone and gonadotropin-releasing hormone on the release of GTH are discussed.