P. Vyboh et al., PLASMA THYROID-HORMONE AND GROWTH-HORMONE PATTERNS IN PRECOCIAL JAPANESE-QUAIL AND ALTRICIAL EUROPEAN STARLINGS DURING POSTNATAL-DEVELOPMENT, Comparative biochemistry and physiology. Part C, Pharmacology toxicology & endocrinology, 114(1), 1996, pp. 23-27
Plasma concentrations of thyroid hormones (TH) and growth hormone (GH)
during postnatal development in the precocial Japanese quail (Coturni
x japonica), and the altricial European starling (Sturnus vulgaris) we
re measured. Developmental changes in plasma TH found in the starling,
differ considerably from those detected in quail. In quail rather hig
h triiodothyronine (T-3) values were measured during the first few day
s after hatching. Subsequently a steady decrease of plasma T-3, to adu
lt levels, was observed. Thyroxine (T-4) concentrations did not change
significantly during the period studied. In starlings, on day 1, plas
ma T-3 was low and T-4 was at or below the assay detection limit. An i
ncrease in concentrations of both hormones occurred between day 1 and
day 5 after hatching. A gradual increase of T-4 occurred afterwards, w
hile plasma T-3 levels remained nearly constant during this growing pe
riod. Plasma GH concentrations showed a similar pattern in both specie
s. There was an increase during first days after hatching and GH conce
ntrations peaked at day 7 in quail and day 5 in starlings. A subsequen
t decrease was observed in both species. Although the GH profiles in s
pecies studied were comparable, there were noticeable differences in t
heir growth rates. Thus different developmental strategies have been r
eflected in different developmental patterns of TH in precocial Japane
se quail and altricial European starling whereas developmental changes
of GH levels were similar in both species.