|
|
||||||||
Inhibin bioactivity and mRNA for inhibin subunits were measured in four dog Sertoli cell tumours and in the testes of five normal control dogs. The tumours contained increased levels of inhibin (P <0·05) and mRNA for the
and βB subunits when compared with controls, whereas the mRNA for the βA subunit was not detected in tumours or control testes. The inhibin bioactivity was associated with a 32 kDa molecule in both Sertoli cell tumours and normal dog testes; no higher molecular weight forms were found after sodium dodecyl sulphate-polyacrylamide gel electrophoresis.
Peripheral levels of immunoassayable inhibin in dogs with Sertoli cell tumours were higher than those in the controls (P = 0·01), indicating that it might be possible to use this parameter as a marker for Sertoli cell tumours. Other testicular tumours, however, might also secrete immunoactive inhibin. The increased inhibin concentrations are likely to be the cause of the suppressed peripheral levels of FSH (P <0·02). However, peripheral levels of LH (P <0·02) and testosterone (P <0·01) were also suppressed in the dogs with Sertoli cell tumours, whereas the concentrations of oestradiol in the peripheral plasma of both groups did not differ. Finally, i.v. injection of the LHRH agonist buserelin caused a significant increase in LH and testosterone in the control dogs, but not in the dogs with Sertoli cell tumours.
It was concluded that secretory products from the Sertoli cell tumours suppressed pituitary gonadotrophin secretion. It is unlikely that testosterone or oestradiol play a role in this respect. FSH may be suppressed by the high levels of inhibin in tumour-bearing dogs, but it remains unclear whether inhibin or another Sertoli cell product is responsible for the unresponsiveness of the pituitary gland to LHRH and the suppression of LH.
Journal of Endocrinology (1990) 127, 235–242
This article has been cited by other articles:
![]() |
G. P. Risbridger, J. F. Schmitt, and D. M. Robertson Activins and Inhibins in Endocrine and Other Tumors Endocr. Rev., December 1, 2001; 22(6): 836 - 858. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Taniyama, K. Hirayama, K. Nakada, K. Numagami, N. Yaosaka, Y. Kagawa, Y. Izumisawa, T. Nakade, Y. Tanaka, G. Watanabe, et al. Immunohistochemical Detection of Inhibin-{alpha}, -{beta}B, and -{beta}A Chains and 3{beta}-hydroxysteroid Dehydrogenase in Canine Testicular Tumors and Normal Testes Veterinary Pathology, November 1, 2001; 38(6): 661 - 666. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. A. Rahman and I. T. Huhtaniemi Ovarian Tumorigenesis in Mice Transgenic for Murine Inhibin {{alpha}} Subunit Promoter-Driven Simian Virus 40 T-Antigen: Ontogeny, Functional Characteristics, and Endocrine Effects Biol Reprod, April 1, 2001; 64(4): 1122 - 1130. [Abstract] [Full Text] |
||||
![]() |
K. Kananen, Rilianawati, T. Paukku, M. Markkula, E.-M. Rainio, and I. Huhtanemi Suppression of Gonadotropins Inhibits Gonadal Tumorigenesis in Mice Transgenic for the Mouse Inhibin {alpha}-Subunit Promoter/Simian Virus 40 T-Antigen Fusion Gene Endocrinology, August 1, 1997; 138(8): 3521 - 3531. [Abstract] [Full Text] |
||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |