Hisayoshi Ooka

Learn More
PURPOSE Recent studies in humans and mice have demonstrated that intestinal P-glycoprotein plays a causative role in the limited absorption of orally administered paclitaxel. Multidrug resistance (MDR)-reversing agents, such as cyclosporin A and PSC 833, are known to increase the systemic exposure to orally administered paclitaxel by enhancing absorption in(More)
Diets containing tryptophan in concentrations 30 and 40 percent of those fed to controls from weaning to 24-30 months or more, can delay aging in Long-Evans female rats. Mortality among low-tryptophan-fed rats was greater in the juvenile period, but substantially less than controls at late ages. Histological biomarkers of aging were also delayed after(More)
The life durations of hypo- and hyperthyroid Wistar rats were measured under clean conventional conditions. The amount of exogenous T4 (thyroxine), which is sufficient to elevate T4 levels in the blood, decreased with age. The rats which were made hypothyroid by the neonatal T4 treatment had a longer lifespan than control. The lifespans of hyperthyroid(More)
AIMS Although it is commonly recognized that ethanol suppresses gluconeogenesis, the influence of alcohol intake on blood glucose levels remains controversial. Ethanol may act on both glucose production and glucose consumption in the liver. Thus, we studied each effect of ethanol on glucose oxidation, gluconeogenesis, glycogenesis and glycogenolysis in the(More)
Wistar rats were made hypothyroidic by intraperitoneal thyroxine (T4) injection during the first 10 days of neonatal life. Levels of T4, 3,3',5-triiodothyronine (T3), thyroid-stimulating hormone (TSH) and prolactin in the blood of these rats were measured by radioimmunoassay. The T4 levels are about two-thirds of control values up to 20 months of age. T3(More)
Age-related changes in the numbers of mammotrophs, somatotrophs, mammosomatotrophs, and the cells of other types in the anterior pituitary of female Wistar rat were measured by flow cytometry. The mammotrophs increased with age, and the somatotrophs decreased with senescence. The mammosomatotrophs increased remarkably in senescent rats, and these cells of(More)
Long-Evans female rats, 21 days of age, were weaned and placed on a control (Purina Rat Chow) diet, on a tryptophan deficient diet (T-) and on a diet complete in quality (Purina Rat Chow) but restricted to the daily amount consumed by the rats on the T- diet (pair-feeding). All animals were maintained on these diets for 1 and 2 months and then one group of(More)
To study the role of B-cells in the regulation of glucagon secretion by glucose, the rat pancreas was perfused with 0.4 mmol/l diazoxide. Perfusate glucose was 5 mmol/l of a basal concentration, and then was decreased to 1 mmol/l, or was increased to 15 mmol/l. Insulin secretion was suppressed by diazoxide below the detectable level at each glucose(More)
We measured the influence of prolactin-releasing neuropeptides on mammotroph proliferation in cultures of rat adenohypophysis cells using flow cytometry. Angiotensin II (AII) increased mammotroph proliferation. Other peptides with hormone-releasing activities did not promote growth. Tamoxifen inhibited mammotroph proliferation in control and AII-containing(More)