Savino A. D'Angelo

Gonadotrophic Hormone Function in Persistent Estrous Rats with Hypothalamic Lesions.

Summary Electrolytic lesions in pre-optic and anterior hypothalamic areas of the brain induced persistent (frequent) vaginal estrus and uterine hypertrophy in rats examined 25-300 days post-operatively. Gonad weight eventually decreased. Compensatory hypertrophy of ovary after unilateral castration was inhibited in persistent estrous lesioned rat. FSH stores in adenohypophysis were maintained but titers in serum decreased. The results signify that adenohypophysis of persistent estrous lesioned rat loses its capacity to augment secretion of FSH under conditions of enhanced demand (unilateral oophorectomy).

A differential response of the rodent adrenal gland to acute starvation.

Summary The response of the adrenal gland to comparable degrees of acute starvation differs markedly in the rat and guinea pig. The guinea pig: adrenal displays absolute hypertrophy with significantly increased solid content. In the rat, adrenal enlargement is a variable response and, when it occurs, is characterized by discoloration and percentage increase in water content. The solid content is unchanged or reduced. DOCA in high doses decreases the size and the solid content of the rat adrenal in the fed or acutely starved animal of either sex. DOCA in the guinea pig fails to affect adrenal size in the fed animal, and is ineffective in preventing the adrenal hypertrophy of starvation.

I131 and P32 accumulation in anuran thyroid gland in normal and accelerated metamorphosis.

Summary and conclusions 1) The uptake of I131 and P32- by the developing thyroid of Rana tadpoles has been determined in normal and accelerated metamorphosis. Radioactive measurements of the isolated gland (estimated weight, 50-200 μg) disclose a progressive increase in radioiodine accumulation throughout normal development. The effect is not paralleled with radiophosphorus although significantly increased P32 thyroidal uptakes eventually occur in advanced development. Exogenous thyrotrophin augments I131 and P32 accumulation in the thyroids of young tadpoles. The applicability of the thyroidal response to the bioassay of thyrotrophin is discussed. 2) The enhancement of iodine and phosphorus uptake by the larval thyroid is considered to reflect increased tempo of thyroid function in amphibian development. The fundamental role of pituitary-thyroid interaction in anuran metamorphosis is reemphasized.

Influence of cortisone on thyroid-pituitary interaction in normal and goitrous rats.

Summary and Conclusions 1. Cortisone potentiates the effect of PTU on goitrogenesis in rats; a) thyroid and pituitary enlargement is greater than with goitrogen alone, and b) the respective changes in TSH levels of blood and pituitary are augmented. 2. The depressed avidity of thyroid tissue for I131 with PTU) is not influenced by cortisone. 3. The results suggest that the potentiating action of cortisone on goitrogenesis involves augmentation of TSH secretion from the adenohypophysis. The implications are briefly discussed.

Urinary output and phosphorus excretion in human subjects during prolonged exposures at low simulated altitudes.

Conclusion 1. No appreciable change in total urine output from ground level values was found to occur in human subjects during prolonged exposures to simulated altitudes of 8,000 and 10,000 ft. under conditions of restricted food and water intake. 2. The renal excretion of phosphorus was significantly decreased at altitude. 3. These experiments indicate that alteration in the mineral metabolism may occur in the unacclimatized human being at altitudes as low as 8.000 ft.

Effect of Thymus Gland, Thymus Extracts, and Thymus Derivatives on Growth and Metamorphosis of Amphibian Larvae

LTHOUGH LTHOUGH many years have elapsed since experiments were first performed on the thymus gland, the precise physiological role of this organ still has not been definitely established. Considerable interest in the problem has been rearoused recently by the results obtained with Hansons thymus extract by Rowntree and his associates (1936a, b)., and with thymocrescin-another type of thymus extractby Asher (1936) on the development of the rat. The major portion of the work has been conducted on mammals, and for a description of the literature in this field the reader is referred to the reviews by Anderson (1932), Gudernatsch (i937), and Nelson (1939). A considerable amount, however, has also been performed on amphibians. This is not surprising since, in such material, growth and differentiation processes may be favorably studied in large numbers of genetically similar animals in the comparatively short time of the metamorphic period. As in mammals, very few noncontroversial findings have emerged. Gudernatsch (1912, 1917) and Romeis (1914) reported retardation of metamorphosis and increased growth in developing larvae which were fed thymus substance. Since these effects were obviously opposite to those produced by thyroid material, a thymus-thyroid antagonism was postulated. On the other hand, Swingle (1917), Uhlenhuth (1919), Romeis (1925), Abderhalden (1926), and Janes and Segaloff (1938), employing either feeding or immersion techniques, indicated that the thymus gland plays no significant role in amphibian development. Criticism, however, may be lodged against the methods employed by the foregoing investigators. The failure by some to obtain positive results with fed thymus material may possibly be due to a destruction of the active thymic principle, if it does exist, in the alimentary tract. The immersion method, likewise, may be criticized, since its use necessarily implies that the principles can be absorbed through the integument. In view of the recent success obtained with injections of thymus extracts in mammals, it was considered worth while to subject the problem in amphibia to an extensive reinvestigation using the more precise injection technique.