Mammalian and chicken I forms of gonadotropin-releasing hormone in the gonads of a protochordate, Ciona intestinalis.

Two forms of gonadotropin-releasing hormone (GnRH) were isolated from the gonads of the tunicate, Ciona intestinalis. The primary structure of the purified peptides was determined by MS and chemical sequence analysis. Both GnRH forms have blocked NH(2) and COOH termini, and their primary structures are identical to mammalian (mGnRH) and chicken I (cGnRH-I) forms reported previously in vertebrates. A total of 1.2 mg of purified cGnRH-I and 0.98 mg of mGnRH was obtained from 100 g of Ciona gonads. The physiological effects of native GnRHs included the induction of synthesis and secretion of sex steroids from ciona gonads and the secretion of luteinizing hormone from rat pituitary. These results suggest that the primary structure and functional roles of mGnRH and cGnRH-I have been highly conserved throughout evolution of chordates.

Metabolic and ultrastructural aspects of experimental diabetic glomerulopathy.

The effects of alloxan induced diabetes and insulin treatment on rat kidney glomerular ion transport and the oxidative phosphorylation were investigated in order to correlate metabolic and ultrastructural alterations. In alloxan diabetic rats an early decrease of Na+K+ ATPase activity in isolated glomeruli preparations and the subsequent uncoupling of oxidative phosphorylation were observed. These metabolic alterations are associated with structural changes such as the thickening of the basement membrane and the disorganization of both endothelial and mesangial cells. Insulin treatment induces a slow and only partial recovery of metabolic changes. Ultrastructural features of the kidney cortex were almost completely normalized after only two months of insulin treatment.