| First Author | Kanki K | Year | 2000 |
| Journal | Gen Comp Endocrinol | Volume | 119 |
| Issue | 3 | Pages | 276-86 |
| PubMed ID | 11017775 | Mgi Jnum | J:65250 |
| Mgi Id | MGI:1913246 | Doi | 10.1006/gcen.2000.7502 |
| Citation | Kanki K, et al. (2000) Spatio-temporal expression of TSHbeta and FSHbeta genes in normally metamorphosing, metamorphosed, and metamorphosis-arrested hynobius retardatus. Gen Comp Endocrinol 119(3):276-86 |
| abstractText | Expression patterns of TSHbeta and FSHbeta genes were investigated in normally metamorphosing and metamorphosed individuals and in goitrogen-treated (TU-SPC), metamorphosis-arrested larvae of a Japanese salamander, Hynobius retardatus, a particular population of which had been reported to show neoteny. Cloned sequences for Hynobius TSHbeta and FSHbeta covered 66 and 56% of full-length genes, respectively, and both showed relatively high similarity to those of other vertebrates. TSHbeta-expressing cells were observed at the ventro-caudal region of the pars distalis of controls, whereas an extraordinarily large number of cells which occupied the whole area of the pituitary glands strongly expressed TSHbeta in TU-SPCs. In contrast, no FSHbeta-expressing cells were observed in the pituitary glands of controls, whereas several positive cells were observed in the pituitary glands of TU-SPCs. Northern blot analyses revealed a rapid increase of TSHbeta expression in the pituitary gland of TU-SPCs that finally reached the level of 20- to 30-fold as much as that of controls. Surprisingly, the expression of FSHbeta also increased in the pituitary gland of TU-SPCs compared with that of controls. On the other hand, triiodothyronine administration to the control juveniles reduced the expression of TSHbeta compared with saline-administrated controls, suggesting that thyroid hormone (TH) exerts a repressing effect on TSHbeta gene. These results suggest that TSHbeta overexpression in TU-SPCs must be caused by a deprivation of TH which plays a role in the negative feedback system and that FSHbeta expression also might be enhanced by mechanisms similar to those of TSHbeta, probably due to certain overlapping of the endocrinological regulation of TSH and FSH in H. retardatus. Copyright 2000 Academic Press. |
