Prolactin receptor mRNA expression in experimental diabetic nephropathy: Relationship with urinary albumin excretion.

OBJECTIVES: Disturbances of prolactin secretion, peptide hormone produced by the pituitary gland, occur in both the chronic renal failure and in diabetes mellitus. So far, the role that prolactin play in the pathology of diabetic nephropathy progression is still unclear. Therefore, the present study was intended to examine whether the renal mRNA expression of prolactin receptor (PRL-R) is altered in experimental diabetes, and how such changes related to the development of albuminuria.

METHODS: Adult female wistar rats were divided into two groups (n=6/group): control (non-diabetic) and diabetic. Diabetes was induced by a single dose injection of 55 mg/ kg streptozotocin. After ten weeks, renal mRNA expressions of both short and long forms of PRL-R were evaluated by real-time polymerase chain reaction.

RESULTS: Diabetes was associated with increases in urine albumin excretion (UAE), kidney weight/body weight ratio, serum prolactin and the mRNA expression of both long and short forms of PRL-R. Furthermore, UAE was significantly and positively correlated with serum prolactin levels and with mRNA expressions of both short and long forms of PRL-R.

CONCLUSION: These results provide evidence, for the first time, that the development of experimental diabetic kidney disease is associated with increases in the renal expression of PRL-R, suggesting a potential role for prolactin in the development and progression of renal injury secondary to diabetes mellitus.