Rabbit mammary glands receiving prolactin intraductally contain signifiicantly larger amounts of nucleic acids than do the contralateral untreated control glands in the same animal. This suggests that prolactin stimulated the mitotic activity of mammary gland and induced the alveolar formation. Thus, prolactin seems to play an important role in the accomplishment of mammary alveolar growth.

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Effect of hypophysectomy on the uptake of I¹³¹ by the rat thyroid with special reference to temporal relation as well as that of methylthiouracil treatment were investigated with the following results:
The uptake of I131 by the thyroid decreased exponentially with the lapse of time after hypophysectomy. At the end of 16 weeks after the operation it decreased approximately 4.5 per cent of the control. While the change of I¹³¹ amount in the serum was not concerned with the lapse of time after hypophysectomy.
The uptake of I¹³¹ by the thyroid was decreased significantly and the I¹³¹ amount in the serum was increased by methylthiouracil administration.

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Effects of growth hormone and cortisone acetate upon mitotic activity in amphibian tissues were studied.
Following daily administrations of growth hormone in the doses of 2-400γ in total, mitotic stimulation was demonstrated in the regenerating and normal epidermis in the four post-operative day. Also temporal stimulation of mitotic activity was demonstrated in the larval bull frogs six days after injection of the daily dose of 25γ attended with subsequent reduction in activity.
Inhibition of mitotic activity was the case in the epidermis of the normal and the regenerating limb when four consecutive daily injections of cortisone acetate in the dose of 4mg in total were received subcutaneously. But no significant effects could be demonstrated on the mitotic activity of the regenerating epidermis of the adult newt following administration of lower dosage levels of 0.05-2mg in total.
After the inspection of mitosis-rate in the epidermis, replacing cells of the small intestine and cortical parts of the liver of the adult newt received growth hormone and cortisone acetate in the dosage level of 400γ and 4mg in total respectively, only epidermal cells were responsive to the administration of the hormones.

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The sequence of histologic change in the hypothalamo-hypophyseal neurosecretory system of thyroidectomized rats was pursued by means of staining with chrome hematoxylin and phloxine.It was learned that thyroidectomy was followed by a temporary phase of increased secretory activity in the paraventricular nucleus and of marked accumulation of secretory material in the neurohypophysis at the end of 3 post-operative days.However, such an occasional hyper-activity became gradually replaced by the normal moderate behavior in the course of later postoperative days.Neurons of the paraventricular nucleus in thyroidectomized rat appeared considerably susceptible to prevailing states of hormone-unbalance, since histologic pictures in animals killed at the end of 40, 60, 130 and 170 post-operative days respectively were much more inconsistent as compared with those in normal animals.With respect to the supraoptic nucleus no remarkable change was observable with the present operated animals.
No marked differences was observed with respect to histologic pictures of the paraventricular nucleus and the neurohypophysis between thyroidectomized rats and thyroidectomized animals administered with a thyroid preparation, excepting that a number of cells, showing characteristic red pyknosis of the nucleus and marked acidophily together with vacuolization of the cytoplasm, made apparition in the latter animals. A few of such cells were of common occurrence in the supraoptic nucleus even in intact animals, but they were lacking in the paraventricular nucleus both in normal and in thyroidectomized animals in early post-operative periods, which were untreated with the thyroid preparation. It was likely that such a type of the cell indicated a certain physiologic change, rather than pathologic degeneration, of the secretory neuron somata of the supraoptic as well as the paraventricular nuclei in the rat.
The observed difference in the mode of response to thyroidectomy between the supraoptic and the paraventricular nuclei may suggest certain functional difference between the nuclei in relation to possible endocrine co-ordination between the thyroid and the hypothalamic neurosecretion.

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1. Measurement of ascorbic acid content of adrenal medulla of the pig and horse rendered the values of 1.99 and 2.08mg per g wet wt.respectively. These values are comparable with the values for the adrenal cortex, and represent the highest among the values in all the tissues submitted to measurement.
2. It was learned that, so far as a certain amount of reduced ascorbic acid is present in the adrenal medulla homogenate, oxidation of adrenalin does not take place.
3. Autoxidation and oxidation of adrenalin through the agency of cytochrome system are inhibited by the addition of ascorbic acid, and the rate of inhibition is parallel with the concentration of the latter.
4. Data were presented and discussed to the effect that ascorbic acid found abundantly in the adrenal medulla would possibly be concerned with protection from oxidation of high concentration of adrenalin at its site of elaboration.

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Hypothalamic neurosecretion in the dog was observed in the early period of post-natal development with the following results.
The earliest sign of production of secretory material was observed as a kind of nuclear secretion, and the widely known cytoplasmic secretory activity was found to follow the initial activity of the nucleus.
Nuclear secretion was learned to be characteristic to juvenile cells with enlarged nuclei.
Occurrence of nuclear secretion, initiation and development of cytoplasmic neurosecretion showed marked disagreement in the cellular activity between the supraoptic and the paraventricular nuclei in the course of post-natal growth of the dog, which suggests possible functional discrepancy of the nuclei from each other.

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The gonadotropic substances were extracted from salmon pituitaries with 40 per cent ethanol or 2 per cent sodium chloride and purified to some degree with rivanol. The water insoluble fraction of these gonadotropic substances contained follicle stimulating one and the water soluble fraction contained luteinizing one. The latter were precipitated with 50 per cent acetone. The follicle stimulating and immature luteinizing effects of these substances of the salmon were bioassayed on mice.

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1. A possibility of occurrence of a hormonic principle representing presumed neurosecretory control of salt balance in teleosts was examined with the euryhaline cyprinodont Oryzias latipes with positive results.
2. Removal of the caudal aspect of the spinal cord comprising the bulk of organization of the caudal neurosecretory system or transection of the cord at the level cephalad to the site of the system in question induced serious disorder in the adaptive control of Na. No significant change resulted from the operations in total body content of K, while water moved in some measure, largely independently of total Na.
3. Injection of homogenate or crude waterly extract of the caudal portion of the spinal cord of the eel, Anguilla japonica, likewise called forth either depression or elevation of total Na level of the test Oryzias, from which the caudal portion of the spinal cord had been removed off. Such diversified effects of injection were learned to be dependent upon the history of preadaptation of the test animal; decrease of Na took place in the fish that had been kept in isotonic or hypertonic media, while increase of Na resulted in the fish that had been kept in freshwater prior to injection.
4. A view was tentatively proposed that the expected hormone of the caudal neurosecretory system would be responsible for one-way activation of certain target organ (s) which, as the gate (s) for excretion and uptake of Na, might adaptively change the mode of work.
5. Brief considerations were made concerning mainly a possibility of interaction between the caudal neurosecretory system and the widely known hypothalamo-hypophyseal system in the control of salt balance in teleosts in general.

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To obtain the information concerning the relation between the hormone synthetic function and metabolisms of thyroid gland, effects of some metabolic in hibitors upon oxidative, iodine and phosphorus metabolism of surviving beef and dog thyroid slices were studied with the uses of radioactive iodide (I¹³¹) and orthophosphate (P³²). The main results obtained are as follows:
1. Potassium cyanide (1×10^-3M) shows remarkable inhibiting effect, in the same grade, upon oxygen consumption (“oxidation”), I¹³¹ uptake, iodine metabolism (“iodination”) and incorporation of radioactive phosphate into acid-soluble organic phosphate fraction (“phosphorylation”) of beef thyroid slice.
2.2, 4-Dinitrophenol (DNP) in the concentrations of 1×10^-5M, augments “oxidation”, while it inhibits “iodination” and “phosphorylation” of beef thyroid slice to a similar extent, showing an intimate relation between phosphorylation and iodination. In higher concentrations (5×10^-5 to 1×10^-4M) DNP decreases “oxidation” as well as “iodination” and “phosphorylation”.
3. Methylthiouracil (MTU) in concentrations of 1×10^-4 to 1×10^-3M, has no effect on “oxidation” while it shows completely blocking effect on organic binding of iodine. However, “phosphorylation” is slightly inhibited by MTU (1×10^-4M) and is inconsiderably increased in lower concentration (1×10^-4M). In accordance with decrease of phosphorylation, iodination is also inhibited by MTU (1×10^-3M).
4. Glucose (100mg/dl), succinate (0.01M) and glutamate (0.01M) decrease “iodination” of dog thyroid slice despite increase of “oxidation” in the case of succinate. “Phosphorylation” of beef thyroid slice is not affected by the additions of glutamate and succinate. Glucose exerts an increasing effect of “phosphorylation”.
5. The significance of the present results on the relation between energy metabolism and function of thyroid gland was discussed.

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