Calf Thyroid Research Articles

Experimental studies on the correlation between male hormones and the pituitary-thyroid system

The correlation between female gonads and pituitary-thyroid system has been discussed very often in the realm of endocrinology and gynecology. As regard to the influence of male gonads upon pituitary-thyroid system there are still many discrepancies of opinion about the result of experimental studies. One of the reasons of such diverse opinions consists in the lack of an appropriate method for the direct measurement of thyrotropin (hereafter abbrev. as TSH) activity in blood. Ogura et al. of our clinic developed a new method for the direct measurement of plasma TSH activity using I131-release method of calf thyroid slices with Warburg apparatus.The author therefore tried to study the influence of castration and male hormone administration, i.e., testosterone propionate (abbrev. as T.P.) and Methylandrostendiol (abbrev. as MAD) upon the plasma TSH activity of normal and thyroidectomized dogs with Ogura's method. The serum PBI level was also determined on normal and castrated dogs, further more on castrated dogs treated with T.P. successively using Barker's method.The results are summarized as follows : 1) The castrated male adult dogs showed a transient elevation of plasma-TSH activity up to the 9th day after castration. A rather sharp decrease of plasma-TSH activity was observed thereafter, reaching it's lowest limit in postoperative 30-60days. The plasma-TSH level then turned to increase but it remained still in subnormal level even 120 days after castration.2) The plasma-TSH level of thyroidectomized dogs showed marked increase after the operation. If these thyroidectomized dogs are castrated, the elevated plasma-TSH volue turns directly to decrease, showing no transient increase, which was observed on nonthyroidectomized dogs. The plasma-TSH value reached the lowest level in between 8-14 days after castration, then it began to increase gradually but even 100 days after castration it remained still in a lower level than preoperative niveau.3) Injection of T.P. to the male castrated dogs produced elevation of plasma-TSH value. Simultaneous observation of serum PBI showed also an 'elevated value. The most marked increase of plasma-TSH was observed with single injection of testostererone heptanoate in doses of 5.0mg/kg of body weight, then T.P. 1.0mg/kg/day and 0.5mg/kg/day for three successive days followed the former. Single injection of T.P. in doses of 1.0mg/kg, 5.0mg/kg and 0.1mg/kg brought about also a slight increase of plasma-TSH value in order.4) The castrated dogs responded with greater percent inerease of plasma-TSH upon the injection of T.P. as compared with the castrated-thyroidectomized dogs. A Plausible explanation of this phenomenon was sought in the lowered reactivity of elevated plasma-TSH of the thyroidectomized dogs.5) The decrease of plasma-TSH value on the castrated dogs and the increase of the value upon injection of T.P. are most plausibly explained from the antagonism of TSH-producing activity and gonadotropin-producing activity of anterior pituitary.6) Injection of MAD showed no apparent influence upon the plasma-TSH level of male castrated dogs and castrated-thyroidectomized dogs. MAD seems to have no effect upon pituitary-thyroid system.Following the report I, the behavior of thyroid gland under castration or male hormone administration was observed. Normal and castrated adult male dogs under thyroid-constant feeding were used in the following experiment to observe the behavior of the thyroid gland. The thyroid gland was totally resected under Isozol-anesthesia and the following examinations were carried out on them.1) Papar radiochromatography of the iodinized amino acid fractions of the thyroid gland.The gland was homogenized with NH4OH-NH4C1 buffer, then digested with trypsin and urea.' The butanol extract of trypsin digest was examined on paper-radiochromatography.

Clinical and Experimental Studies on the Correlation between Thyroid Gland and Diabetes Mellitus

1) This article summarily discusses the experimental results of the effects of the thyroid hormone on carbohydrate metabolism. The present investigation was carried out by the departmental staffs.2) Serum P.B.I., I131 uptake, basal metabolism and cholesterol contents of 62 diabetic patients admitted to our hospital were determined. Two of the 62 patients had hyperthyroidism, of the two one had devloped hyperthyroidism during the course of diabetes mellitus, which was improved by treatment for hyperthyroidism. Generally speaking, severe diabetic patients, having high fasting blood sugar and severe form of glucose tolerance test, were apt to show hypothyroidism.3) A new method to determine T.S.H. in vitro was recently desingned by appling what I131 release-inhibiting ratio in calf thyroid slice run paralelled with standard T.S.H. concentration (U.S.P.) (Bakke-Ogura modification for plasma T.S.H. determination). By means of this method the normal plasma T.S.H. level was 0.69±0.51 m J.S.E. per ml.The patients with moderately advanced and severe diabetes mellitus were apt to show elevated plasma T.S.H., especially in three juvenile diabetic patients.4) Relatively large number of the patients revealed low serum P.B.I. with elevated T.S.H., as the correlation of these two substances were checked in all the diabetic patients. The investigation is being continued for further clarification.5) The effects of thryoxine and triiodothyronine on carbohydrate metabolism were investigated in vitro, i.e. these hormones accelerated glucose uptake and glycogen synthesis of rat diaphragm and antagonized insuline effects. However, they are antagonistic in two ways, glycolysis and glycogen synthesis, are accelerated in rat liver slice by the hormones. Thyroxine failed to show any effect on oxygen consumption of brain slice.6) The thyroid function of the alloxan diabetic rat was investigated subsequently by means of I131 radioautograph and thyroid function index.* The following results were obtained. The thyroid function was apt to be increased in the early stage, but was generally decreased in the later stage of the alloxan diabetes. With insulin treatment for the lowered thyroid function in the later stage, the function was able to be improved.* Thyroid function index = I131 uptake% /thyroid weight / body weight/x 100

THE ACCUMULATION OF THYROXINE-LIKE AND OTHER IODINE COMPOUNDS IN THE FETAL BOVINE THYROID1

The allometric constant (k in the equation y = bxk) for thyroid weight as a function of body weight in the fetal calf was shown to be 1.0. This indicates that the growth of the thyroid gland in the fetal calf is almost directly proportional to body weight. Although the above formula was originally used in connection with morphological dimensions, it has been widely applied to chemical magnitudes by Needham (1942) who has termed such studies chemical heterogeny. Thus, in the allometric equation y = bxk, y becomes the chemical entity and x the morphological magnitude (body weight, crown-rump (C.R.) length, or age in days). In the present investigation, the accumulation of two chemical fractions, thyroxine-like and non-thyroxine iodine, was observed in the fetal calf thyroid from 53 days to term. The amounts found were correlated with body weight, C.R. length, and age of the fetus.