Thyroid hormone effects on chick scale morphogenesis and keratinization

Development ◽  
1970 ◽  
Vol 24 (1) ◽  
pp. 65-71
Author(s):  
Nancy K. Lawrenz ◽  
Leland G. Johnson
Keyword(s):  
Thyroid Hormone ◽  
Scale Development ◽  
New Hampshire ◽  
Chick Embryos ◽  
White Leghorn ◽  
Endocrine Effects ◽  
Hormone Effects ◽  
Hormone Responsiveness

The effects of thiourea injection on scale development were studied in New Hampshire Red × White Leghorn Cross chick embryos. Normal morphogenesis and keratinization of scales were significantly delayed in thioureatreated specimens. Subsequent thyroxine injection resulted in normal or even precocious scale development. The thyroid hormone responsiveness of scale development is discussed in relation to other studies of endocrine effects on differentiation of skin and skin derivatives.

Dexamethasone Effect on Embryonic Chick Respiratory Epithelium

1982 ◽  
Vol 40 ◽  
pp. 248-249
Author(s):  
M.R. Richter ◽  
R.V. Blystone
Keyword(s):  
Lung Development ◽  
Critical Role ◽  
Respiratory Epithelium ◽  
Chick Embryos ◽  
Embryonic Chick ◽  
White Leghorn ◽  
Lung Maturation ◽  
Synthetic Analogs ◽  
Lung Physiology ◽  
Avian Lung

Dexamethasone and other synthetic analogs of corticosteroids have been employed clinically as enhancers of lung development. The mechanism(s) by which this steroid induction of later lung maturation operates is not clear. This study reports the effect on lung epithelia of dexamethasone administered at different intervals during development. White Leghorn chick embryos were used so as to remove possible maternal and placental influences on the exogenously applied steroid. Avian lung architecture does vary from mammals; however, respiratory surfactant produced by the lung epithelia serves an equally critical role in avian lung physiology.

scholarly journals Development of the Testes and Combs of White Leghorn and New Hampshire Cockerels

1942 ◽  
Vol 21 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Jesse E. Parker ◽  
Fred F. McKenzie ◽  
H.L. Kempster
Keyword(s):  
New Hampshire ◽  
White Leghorn

scholarly journals A production trial with layers of four hybrids under different environmental conditions in the Eastern Province of Saudi Arabia.

1971 ◽  
Vol 19 (4) ◽  
pp. 204-210
Author(s):  
H. Appelman ◽  
B.J. Bonhof
Keyword(s):  
Saudi Arabia ◽  
Rhode Island ◽  
New Hampshire ◽  
Egg Production ◽  
Live Weight ◽  
Egg Mass ◽  
White Leghorn ◽  
Eastern Province ◽  
Egg Weight ◽  
Food Consumed

161 Australorp X Rhode Island Red (RIR) X New Hampshire (NH) and 166 White Leghorn (WL) imported fowls were kept in insulated housing; 161 Australorp X RIR X NH, 166 WL, 154 RIR X WL and 148 RIR X NH X RIR fowls were kept in open houses. In the 6 groups resp., live weight at 126 days of age averaged 1602, 1227, 1578, 1234, 1397 and 1539 g, food consumption 4.02, 4.49, 4.03, 4.47, 4.25 and 4.17 kg/kg gain, overall laying percentage 56.6, 56.4, 52.5, 53.4, 55.0 and 37.5, egg production/hen 202, 201, 188, 191, 196 and 134, and egg weight 56.3, 56.3, 55.0, 55.8, 55.0 and 57.5 g. Egg mass averaged 1335, 1323, 1191, 1151, 1126 and 796 kg and food consumed/kg eggs produced 3.68, 3.53, 3.71, 3.25, 3.37 and 4.74 kg. Live weight at 16 mth of age averaged 2894, 2040, 2665, 1874, 2132 and 2517 g, and mortality 12.8, 11.1, 33.6, 43.5, 52.8 and 50.4%. (Abstract retrieved from CAB Abstracts by CABI’s permission)

In vivo regulation of β-MHC gene in rodent heart: role of T3 and evidence for an upstream enhancer

1999 ◽  
Vol 276 (4) ◽  
pp. C883-C891 ◽  
Author(s):  
Carola E. Wright ◽  
F. Haddad ◽  
A. X. Qin ◽  
P. W. Bodell ◽  
K. M. Baldwin
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Reporter Gene ◽  
Normal Control ◽  
Transcriptional Activity ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Promoter Construct ◽  
Hormone Responsiveness

Cardiac β-myosin heavy chain (β-MHC) gene expression is mainly regulated through transcriptional processes. Although these results are based primarily on in vitro cell culture models, relatively little information is available concerning the interaction of key regulatory factors thought to modulate MHC expression in the intact rodent heart. Using a direct gene transfer approach, we studied the in vivo transcriptional activity of different-length β-MHC promoter fragments in normal control and in altered thyroid states. The test β-MHC promoter was fused to a firefly luciferase reporter gene, whereas the control α-MHC promoter was fused to the Renilla luciferase reporter gene and was used to account for variations in transfection efficiency. Absolute reporter gene activities showed that β- and α-MHC genes were individually and reciprocally regulated by thyroid hormone. The β-to-α ratios of reporter gene expression demonstrated an almost threefold larger β-MHC gene expression in the longest than in the shorter promoter fragments in normal control animals, implying the existence of an upstream enhancer. A mutation in the putative thyroid response element of the −408-bp β-MHC promoter construct caused transcriptional activity to drop to null. When studied in the −3,500-bp β-MHC promoter, construct activity was reduced (∼100-fold) while thyroid hormone responsiveness was retained. These findings suggest that, even though the bulk of the thyroid hormone responsiveness of the gene is contained within the first 215 bp of the β-MHC promoter sequence, the exact mechanism of triiodothyronine (T3) action remains to be elucidated.

A comparison of purebred and strain-cross New Hampshire hens as dams

1986 ◽  
Vol 26 (3) ◽  
pp. 291
Author(s):  
RW Polkinghorne
Keyword(s):  
New Hampshire ◽  
Reciprocal Effects ◽  
White Leghorn ◽  
Reciprocal Crosses

Two purebred New Hampshire strains and their reciprocal crosses were investigated as dams when mated to White Leghorn sires. Considerable heterosis was found in the strain-cross New Hampshire hens for the production characters measured, and no important reciprocal effects were detected. As no disadvantages were detected in the performance of progeny, it was concluded that appropriately chosen strain-cross hens can be used as a means of increasing the productivity of breeder dams.

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