XB-ART-19690J Vet Med Sci 1995 Jun 01;573:539-42. doi: 10.1292/jvms.57.539.
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Immunohistochemical studies on the development of TSH cells in the pituitary of Xenopus laevis larvae.
Since thyroid-stimulating hormone (TSH) producing cells are thought to play an essential role during metamorphosis, their development was immunohistochemically examined to reveal the appearance and topographical changes in the distribution in the hypophysis of Xenopus laevis tadpole from hatching to the end of metamorphosis. TSH-immunoreactive cells initially appeared at stage 49 (just the beginning of development of the pars nervosa in the hypophysis) as small clusters in the middle part of the pars distalis. They showed conspicuous changes in number during late premetamorphosis: their number reached a peak at stage 51, suddenly decreased at stage 52 (just before completion of the hypophysial histogenesis) followed by gradual increase until the end of metamorphosis. At later stages, they were restricted to the posterior half of the pars distalis.
PubMed ID: 7548415
Article link: J Vet Med Sci
Species referenced: Xenopus laevis
Genes referenced: tshb
Antibodies: Tshb Ab1
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|Table 1. Stage criteria and hypophysial differentiation during the development of Xenopus laevis NF-stage Age General survey of development (days) 1:36' 2.1 37/38 2.2 39 2.4 40 2.8 41 3.2 42 3.3 43 I I 3.6 44 ! 3.8 A 45 '' 4.1 46 I 4.4 47 5.5 48 7.5 49 12 50 15 51 17 52 21 53 54 1 ~ 55 32 56 33 57 41 B 58 44 :~ 48 Hatching Existence of hypophysial anlage Beginning of intestinal tract coiling Appearance of dermal color adaptation Beginning of segregation of primordial germ cells from dorsal endoderm Appearance of adrenal cortex anlage Appearance of thyroid anlage Beginning of feeding Appearance of hindlimb bud Beginning of differentiation in pars imermedia of adenohypophysis Appearance of forelimb bud Beginning of development in pars nervosa Formation of complete gonadal rudiments Beginning of sexual differentiation of gonads Completion of hypophysial histogenesis First meiotic division in ovary Appearance of forelimbs Ultimate length of larva First meiotic division in testis Beginning of head narrowing --------------------------- ! 62 49 Beginning of tail shrinkage 63 51 c 64 53 I 65 54 f 66 58 Completion of metamorphosis A: Premetamorphosis, B: Prometamorphosis, C: Climax (Terminology used by Etkin ) really useful chart of xenopus stages and developmental landmarks|
|Figs. 1-4. Sagittal section stained with anti-TSH serum. Fig. 1. First appearance ofTSH cells with weak immunoreactivity at stage 49 in the middle part of the pars distalis (arrow). X 230. Fig. 2. TSH cells with intense immunoreactivity at stage 51. x 230. Fig. 3. Abrupt decrease in number of TSH cells at stage 52. x 230. Fig. 4. TSH cells in the posterior half of the pars distalis at stage 66. x 230. RI: Recessus infundibularis|