Masaru Wada

Uptake of peroxidase from the third ventricle by ependymal cells of the median eminence

SummaryPeroxidase injected into the subarachnoid space in mice is absorbed by ependymal cells of the median eminence. The ependymal cells of the median eminence of the rat and Japanese quail absorb peroxidase injected into the third ventricle. The processes of these ependymal cells terminate at the capillaries of the primary plexus or those surrounding the ventromedial nucleus of the hypothalamus. In all three species, peroxidase is absorbed by the ependymal cells of the paraventricular organ and by those in close proximity to it. Some ependymal cells send processes to the capillaries in the lateral nucleus of the hypothalamus. These phenomena are discussed in relation to adenohypophysial function.

Induction of drinking in the white-crowned sparrow, Zonotrichia leucophrys gambelii, by intracranial injection of angiotensin II.

In the White-crowned Sparrow, Zonotrichia leucophrys gambelii, single injections of 0.5 μg (ca. 500 pmoles) angiotensin II into the preoptic region, anterior hypothalamus, and lateral hypothalamus induce drinking. The minimum effective dosage is higher than in the white rat and the latency of effect is somewhat greater.

Effect of hypothalamic implantation of testosterone on photostimulated testicular growth in Japanese quail (Coturnix coturnix japonica)

SummaryTestosterone pellets implanted in the third ventricle inhibited completely photostimulated testicular growth in the Japanese quail (Coturnix coturnix). Crowing was induced by intraventricular testosterone in quail with undeveloped testes. Intraventricular cholesterol pellets did not inhibit testicular growth. In these birds crowing occurred normally. When the testosterone implants were located in the nucleus tuberis, photoperiodically induced testicular growth was also prevented. Testosterone implants in several other nuclei did not impair testicular growth. These observations suggest that testosterone is involved in the hypothalamo-gonadal negative feedback mechanism in this species, and the nucleus tuberis is the site of tetsosterone action.

Cell types in the adenohypophysis of the Japanese quail and effects of injection of luteinizing hormone-releasing hormone

SummaryThe cells of the adenohypophysis of the Japanese quail were studied by both light and electron microscopy after exposure to long photoperiods or injection of luteinizing hormone-releasing hormone (LRH). Six cell types were identified in the adenohypophysis by examining alternate thick and thin sections by light and electron microscopy.In the cephalic lobe, there are four types of glandular cells. They are the prolactin cells, ACTH cells, TSH cells, and gonadotropic cells (FSH ?). In the caudal lobe, there are two types of cells, STH cells and gonadotropic cells (LH ?).After exposure to long daily photoperiods, gonadotropic cells in both lobes were strongly activated. They became larger and accumulated many granules. ACTH cells became vacuolated; granules were sparse.Synthetic LRH injection (10 μg/0.2 ml/day) for 10 days to the non-photostimulated quail stimulated certain numbers of the gonadotropic cells in the both lobes, although the response of the cells was less than that induced by photostimulation. No response was seen in the other cell types.

Effect of prolactin on thyroid function in Japanese quail (Coturnix coturnix japonica)

Abstract Ovine prolactin administration in doses of 10 and 50 IU given over periods of 10 or 20 days induced hypertrophy of the epithelial cells of the thyroid gland in Japanese quail. A decrease of serum thyroxine was observed in the birds that received prolactin (10 or 50 IU) for 10 days, but not in the birds injected with the same doses for 20 days. Prolactin seems to act at the thyroid level to inhibit thyroxine secretion, resulting in hypertrophy of the gland presumably through negative feedback. Prolactin also induced fat deposition.

Immunohistochemical localization of LH-producing cells in the adenohypophysis of the Japanese quail, Coturnix coturnix japonica

SummaryThe cells that produce luteinizing hormone (LH) in the adenohypophysis of the Japanese quail were identified immunohistochemically using anti-chicken LH serum and horseradish peroxidase-labeled goat anti-rabbit gamma globulin serum. The LH cells are localized in the caudal lobe of the pars distalis. They are elongate in shape and are polarized toward the sinusoids, especially in their active states. Alterations in size of LH cells are directly related to changes in circulating LH levels as induced by castration or photostimulation. The LH cells identified immunohistochemically were only stained by alcian blue with periodic acid-Schiff (PAS), alcian blue and orange G.PAS-positive gonadotropic cells in the cephalic lobe were stained immunohistochemically only slightly if at all using anti-chicken LH serum and consequently may be FSH producing cells. In the cephalic lobe another type of basophilic cell was stained with alcian blue. These cells were also stained immunohistochemically with anti-chicken LH serum. These cells may possibly be identified as TSH cells due to the characteristics of the antichicken LH serum used in this study which cross react with LH and TSH but only slightly with FSH, and also on the basis of previous light and electron microscopic studies.

Effect of hypothalamic implantation of puromycin on photostimulated testicular growth in the Japanese quail (Coturnix coturnix japonica).

Abstract When a mixture of puromycin and cholesterol (1:50 by weight) was implanted in the anterior part of the nucleus tuberis, photostimulated testicular growth and development of the cloacal protrusion were impaired. When the implants were placed in the posterior part of the nucleus tuberis testicular growth was not affected, but development of the cloacal protrusion was inhibited. Implants in other hypothalamic areas had no effect on the development of the testes or the cloacal protrusion. These results suggest that the nucleus tuberis is the site of synthesis of the gonadotropin-releasing factor(s) and that their production and release are induced by photostimulation.

The implantation of puromycin into the neurosecretory nuclei of the rat

SummaryFollowing the bilateral implantation of puromycin into the paraventricular nuclei of rats, the neurosecretory cells became atrophic and the amount of aldehyde-fuchsin (AF) positive material in the neural lobe decreased. In these rats, urine excretion and water intake increased remarkably. The supraoptic nuclei of the rats were not affected by this treatment. After the unilateral implantation of puromycin in the paraventricular nucleus, the neurosecretory cells of the implanted side became atrophic, while those of the unimplanted side hypertrophied. The neural lobe contained similar amounts of AF-positive material to those of the control rats with unilateral cholesterol implants. In the rats implanted bilaterally with puromycin immediately above the supraoptic nucleus, the neurosecretory cells of this nucleus contained little or no AF-positive material, and urine excretion and water intake increased greatly. The cells of the paraventricular nucleus remained unchanged in these rats.