Thyroid Feeding From Conception and Hypo-thalamo Pituitary-Adrenal Axis Response in 30-Day-Old Rats

Elevation of thyroid status in preand postnatal rats has been previously shown to accelerate the development of the neuroendocrine axis controlling adrenal response to stress. The present study determined the influence of feeding desiccated thyroid powder (0.03%) in the maternal diet from conception until young were 30 d old. Circulating corticosterone levels were compared in control and thyroid-fed young before stimulation, after a general stress (one min exposure to ether fumes), direct adrenal stimulation (subcutaneous adrenocorticotropin (ACTH) injection) or control injection (physiological saline subcutaneously). Corticosterone levels were measured by both fluorometric assay and radioimmunoassay (RIA). These comparisons revealed that thyroid feeding did not significantly influence basal corticosterone levels, or response to general stress or saline injection. However, injected ACTH stimulated a significantly greater adrenal response in controls than thyroid-fed rats. Since responses relying on endogenous ACTH were not altered by thyroid feeding, it is suggested that absorption of subcutaneously injected ACTH was subnormal in the experimental animals. Results were similar for both assay techniques, indicating that the advantages of precision and specificity given by RIA over fluorometric assay were not critical in this study. OHIO J. SCI. 85 (1): 17-22, 1985

[1]  V. S̆trbák,et al.  Thyroid hormones in milk: physiological approach--a review. , 1983, Endocrinologia experimentalis.

[2]  E. L. Besch,et al.  Radioimmunoassay (RIA) of Serum Corticosterone in Rat 1 2 , 1982, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[3]  J. Rabii,et al.  Maturation of adrenal stress responsiveness in the rat. , 1980, Neuroendocrinology.

[4]  R. Rubin,et al.  Postnatal Maturation Patterns of Serum Corticosterone and Growth Hormone in Rats: Effect of Chronic Thyroxine Administration , 1979, Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme.

[5]  J. Finkelstein,et al.  Growth hormone secretion in hyperthyroidism. , 1974, The Journal of clinical endocrinology and metabolism.

[6]  J. Davenport,et al.  Neonatal thyroxine stimulation in rats: accelerated behavioral maturation and subsequent learning deficit. , 1973, Journal of comparative and physiological psychology.

[7]  N. H. Bass,et al.  Adverse effects of excess thyroid hormone on the maturation of rat cerebrum. , 1973, Archives of neurology.

[8]  J. Leathem,et al.  Hypothyroidism and the maturation of the hypothalamo-hypophyseal-adrenal axis. , 1973, Developmental psychobiology.

[9]  P. Nakane,et al.  Adrenal and plasma corticosterone and vitamin A in rat adrenal glands during postnatal development. , 1967, Endocrinology.

[10]  S. Schapiro.  Metabolic and maturational effects of thyroxine on the infant rat. , 1966, Endocrinology.

[11]  E. Geller,et al.  Neonatal Adrenal Cortical Response to Stress and Vasopressin.∗ , 1962, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[12]  M. Obregon,et al.  L-thyroxine and 3,5,3'-triiodo-L-thyronine in rat embryos before onset of fetal thyroid function. , 1984, Endocrinology.

[13]  Meserve La,et al.  Altered growth patterns and depressed pituitary growth hormone content in young rats: effects of pre- and postnatal thiouracil administration. , 1982 .

[14]  A. Tenore,et al.  Effect of triiodothyronine injection on levels of triiodothyronine and thyroid-stimulating hormone in sera and milk of lactating rats and in sera of their sucklings; precocious development of jejunal alpha-disaccharidases in the sucklings. , 1980, Biology of the neonate.