ABSTRACT
To investigate biological rhythms of the thyroid gland circannual oscillations of thyroxine (T4), triiodothyronine (T3), and thyrotropin (TSH) were compared in serum samples of untreated young male Wistar-rats with the circannual changes of thyroid weights and with the relative proportion of colloid, epithelium, and interstitium of the thyroids. Animals were kept under standard environmental conditions, however, lighting conditions simulated the natural day-night changes. Thyroid weights, T4, T3, and TSH showed a statistically significant circannual rhythm with maxima in winter and spring and minima in summer and autumn. The same circannual patterns were observed in the proportion of epithelium and interstitium of the thyroids, while the colloid exhibited an inverse circannual pattern. These data were verified by biomathematical methods, like locally adjusted functional approximation, analysis of variance, and Spearman rank correlation. Our results represent an example for the concordance between functional and morphometrical changes in the course of circannual oscillations. Furthermore, these data confirm our earlier results describing higher T4-levels in the winter time (short-day) and lower serum titers in the summer time (long-day).
Subject(s)
Periodicity , Thyroid Gland/metabolism , Thyrotropin/blood , Thyroxine/blood , Triiodothyronine/blood , Animals , Epithelial Cells , Male , Microscopy/methods , Organ Size , Radioimmunoassay , Rats , Rats, Inbred Strains , Seasons , Software , Thyroid Gland/anatomy & histology , Thyroid Gland/cytologyABSTRACT
In 19 patients with Turner's syndrome aged from 12 to 24 years (average age 17.0 years) the influence of mestranol and chlormadinone acetate on both basal and TRH stimulated TSH secretion, total thyroxine (T4), thyroxine binding capacity (TBC) and free thyroxine index (FT4-I) by means of sequential stimulation test (0.5 g arginine hydrochloride/kg body weight, 25 micrograms GnRH and 200 micrograms TRH) was investigated. These investigations were performed before hormonal substitution, during third to 5th cycles of treatment and 4 month after finishing treatment. TSH and T4 serum levels were determined by RIA, TBC by radio reagent assay. The FT4 index was calculated. Mean basal TSH levels both before, during and after hormonal treatment did not differ. Netto TSH level increase were somewhat higher in 8 of the 19 patients during hormonal treatment. TBC and T4 significantly increased under treatment. The rise of FT4 in a few patients under treatment could not be ensured statistically. After finishing treatment the levels of thyroid parameters decreased.
