Horn, K.

Nolte, J.

Scriba, Peter Christian

English

Open Access LMU

Acta endocrinologica Supplementum 171 Interstitial Gland Tissue of Mammalian Ovary By Sardul S. Guraya P E R I O D I C A • C O P E N H A G E N 1973 19. Symp. Dtsch. Ges. Endokrin. Abstract No. 147 Acta endocr. (Kbh.) Suppl. 173 (1973) 147 Med. Univ.-Klinik, Freiburg1 und I I . Med. Univ.-Klinik, München2 EXPERIMENTAL THYROTOXICOSIS: EFFECTS OF GRADED DOSES OF T 4 PLUS T 3 * /. Nolte*, K. Horn2 and P. C. Scriba2 Earlier studies have shown marked species specific differences of the effects of thyroid hormones on the basal metabolic rate (BMR) and on the induction of en-zyme biosynthesis (1, 2). In order to produce experimental thyrotoxicosis closely resembling the pathophysiological conditions of human thyrotoxicosis, T 4 plus T 3 were applicated in a ratio of 3:1 (w/w), given for a period as long as 30 days and finally used in dosages ranging from very low to high. Groups of rats (160 g) received nightly a limited amount of food containing the desired T 4 / T 3 addition with unrestricted normal diet during the days. The rats were thus taking A : 3.0, B : 17, C : 85, D : 0 jug of a T 4 / T 3 mixture (3 : 1) per 24 hrs. After 30 days the following parameters were estimated: BMR, body weight, heart weight, serum T 4 and T 3 uptake test (3), and induction of liver enzyme acti-vities: glycogen metabolism, glucose oxidation, glycolysis, gluconeogenesis, glyce-rol-1 P -cycle, citrate cycle with side paths and ^-oxidation of fatty acids. As expected, the medium (B) and the high (C) T 4 /T 3 dosage resulted in an eleva-ted BMR and a definite increase of the heart weight, which is a sensitive parameter of adaptation to hypercirculation. Likewise, the activities of enzymes were raised, which are particularily involved in the elevation of the BMR: mitochondrial gly-cerol- 1 P D H , malic enzyme, PEP carboxykinase, NADP: isocitrate D H and glucose-6P D H . Increases of T 4 - I and of T3-uptake were found in groups B (3.5 //g0/o/32°/o) and C (5.2/41) as compared to controls (D : 2.7/30). The lower T 4 found in group A (1.4 /wg°/o) may represent suppression of thyroxine secretion due to exogenous T 3 . The data on BMR, body weight and liver enzyme activities are consistent with the assumption that the rats of group A were still euthyroid. The daily dose of thyroid hormones, which induces a well controlled experimental thyro-toxicosis, may be somewhat less than the amount used for group B. 1. Nolte, J., Pette, D., Bachmaier, B., Kiefhaber, P., Schneider, H., and Scriba, P. C: Eur. J. clin. Invest. 2 (1972) 141. 2. Nolte, J., Brdiczka, D., Scriba, P. C , and Sandte, H. W.: Acta endocr. (Kbh.) Suppl. 159(1972) 11. 3. Horn, K., Habermann, J,, Henner, J., zur Horst, L , and Scriba P. C: Z. anal. Chem. 259 (1972) 222. * Supported by the Deutsche Forschungsgemeinschaft (SFB 51). 147 10* 

Experimental thyrotoxicosis: Effects of graded doses of T4, plus T3

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