Further studies on catecholamine synthesis in the spontaneously hypertensive rat: catecholamine synthesis in the central nervous system

Catecholamine levels, turnover rates and in vivo synthesis rates were measured in the brainstems of spontaneously hypertensive rats (SHR) and two normotensive strains, Wistar/NIH and Wistar/Kyoto. All these parameters of catecholamine metabolism were lower in SHR than in the Wistar/NIH but similar to those in the Wistar/Kyoto, the parent strain of SHR. Examination of the three biosynthetic enzymes in the conversion of tyrosine to norepinephrine indicated that all three strains had similar levels of tyrosine hydroxylase and dopamine-β-hydroxylase activity but that the SHR and the Wistar/Kyoto had markedly reduced dopa decarboxylase activity. In vivo synthesis studies using labeled tyrosine and dopa, however, indicated that the decreased synthesis rate in the SHR as compared to Wistar/NIH is the result of decreased amounts of tyrosine entering the catecholamine pool.     

Increased incorporation of 14C-lysine into vascular proteins of the spontaneously hypertensive rat

The incorporation of ¹⁴C-lysine into heart and vascular proteins of the spontaneously rat (SHR) was compared with that in control animals at different ages. Prior to the development of hypertension (33 days of age), the incorporation rate of lysine into non-collagen proteins of the mesenteric arteries was approximately 2 times greater in the SHR than in normotensive strains. The incorporation rate was similar in the heart, aorta and liver of SHR at this age. The increased incorporation of lysine into the non-collagen proteins persisted at 13 weeks and 15 months of age. As a result of hypertension, the hypertrophy of the he art was reflected in increased lysine incorporation in adult animals and specific differences in heart actomysoin synthesis were observed. In the aorta and mesenteric arteries, elastin as well as other cellular proteins are responsible for the incrrporation. It is suggested that increased protein synthesis in the small vessels of the genetically hypertensive rats may be one of the pathogenic factors in this type of hypertension.     

Evaluation of carcinoembryonic antigen in extramammary Paget''s disease

An autopsied case of extramammary Paget's disease associated with the elevation of serum CEA level is reported. An abnormally high level of serum CEA was found in 46% of patients with this disease.     

Therapeutic potential of (-)-epigallocatechin 3-O-gallate on renal damage in diabetic nephropathy model rats

Previous investigations have demonstrated that green tea polyphenols and partially hydrolyzed guar gum as dietary fiber have antioxidative and hypolipidemic activity, respectively, supporting their reduction of risk factors in the course of diabetic nephropathy via a hypoglycemic effect and ameliorating the decline of renal function through their combined administration to rats with subtotal nephrectomy plus streptozotocin (STZ) injection. As a further study, we examined whether (-)-epigallocatechin 3-O-gallate (EGCg), the main polyphenolic compound, could ameliorate the development of diabetic nephropathy. Rats with subtotal nephrectomy plus STZ injection were orally administrated EGCg at doses of 25, 50, and 100 mg/kg body weight/day. After a 50-day administration period, EGCg-treated groups showed suppressed hyperglycemia, proteinuria, and lipid peroxidation, although there were only weak effects on the levels of serum creatinine and glycosylated protein. Furthermore, EGCg reduced renal advanced glycation end-product accumulation and its related protein expression in the kidney cortex as well as associated pathological conditions. These results suggest that EGCg ameliorates glucose toxicity and renal injury, thus alleviating renal damage caused by abnormal glucose metabolism-associated oxidative stress involved in renal lesions of diabetic nephropathy.