Thesis (Ph. D.)--Columbia University, 1943. / Cover title. Vita. Includes bibliographical references.

No description available.

Thesis (Ph. D.)--University of Chicago, 1940. / Lithoprinted. Bibliography: p. 19-20.

The effect of various concentrations of thiourea on the production of thyroid hormones was investigated in the starry flounder, Platichthys stellatus. Flounder were immersed in sea water solutions of thiourea in concentrations of 0.0001%, 0.0005%, 0.001% and 0.0025% for periods of 10 - 11 days and in concentrations 0.005%, 0.01%, 0.02% and 0.03% for as long as 74 days. After injections of tracer doses of radioiodine, extracts of the thyroid glands were subjected to autoradiochromatography. It was established that concentrations of thiourea ranging from 0.0025% - 0.03% completely inhibited the synthesis of the thyroid hormones throughout the course of the experiments. Although the synthesis of the thyroid hormones was abolished in flounder exposed to 0.0025% and higher concentrations of thiourea, flounder in some instances were able to synthesize moniodotyrosine and diiodotyrosine. The significance of this phenomenon is discussed in connection with biosynthesis of the thyroid hormones and the mechanism of antithyroid activity of thiourea. Measurement of the percentage uptake of the injected dose of radioiodine revealed that inhibited flounder consistently had lower values in the thyroid when compared to controls. / Science, Faculty of / Zoology, Department of / Graduate

Thesis--Helsinki. / Includes five papers on which the present dissertation is based (p. 61-131). Includes bibliographical references.

Thesis--Helsinki. / Includes five papers on which the present dissertation is based (p. 61-131). Includes bibliographical references.

No description available.

Male and female alligators ranging from 58 cm to 361 cm in length (N=1054) were captured and their blood was sampled between 9 A.M. and midnight from June 2000 - June 2002 at the Rockefeller Wildlife Refuge in Grand Chenier, LA. Animals were captured in a variety of habitats including marsh, open water, canals, and ponds. Total thyroid hormones were measured by radioimmunoassay. Four criteria were used to evaluate changes in hormone levels: sex, total length, season, and time of day. Thyroxine (T4) varied over a wide range from 0.5 to 57 ng/mL. Triiodothyronine (T3) levels were below the sensitivity of the assay (<0.6ng/mL). A distinct seasonal peak in T4 was observed between December and April, peaking in March with highest mean T4 levels observed in the spring. Mean T4 declined significantly from the spring to an intermediate summer mean and declined significantly again in the winter. No T4 differences between the sexes were observed. Mean T4 was highest in juveniles, significantly lower in subadults, and significantly lower still in adults. Highest levels were found between 5 P. M. and midnight. With values up to 57 ng/ml in the spring, alligators exhibit T4 levels among the highest recorded for reptiles.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Joseph Travis, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed Apr. 12, 2004). Includes bibliographical references.

Male and female alligators ranging from 58 cm to 361 cm in length (N=1054) were captured and their blood was sampled between 9 A.M. and midnight from June 2000 - June 2002 at the Rockefeller Wildlife Refuge in Grand Chenier, LA. Animals were captured in a variety of habitats including marsh, open water, canals, and ponds. Total thyroid hormones were measured by radioimmunoassay. Four criteria were used to evaluate changes in hormone levels: sex, total length, season, and time of day. Thyroxine (T4) varied over a wide range from 0.5 to 57 ng/mL. Triiodothyronine (T3) levels were below the sensitivity of the assay (<0.6ng/mL). A distinct seasonal peak in T4 was observed between December and April, peaking in March with highest mean T4 levels observed in the spring. Mean T4 declined significantly from the spring to an intermediate summer mean and declined significantly again in the winter. No T4 differences between the sexes were observed. Mean T4 was highest in juveniles, significantly lower in subadults, and significantly lower still in adults. Highest levels were found between 5 P. M. and midnight. With values up to 57 ng/ml in the spring, alligators exhibit T4 levels among the highest recorded for reptiles.