The augmentation of pituitary adenylate cyclase-activating polypeptide (PACAP) in streptozotocin-induced diabetic rats

Peptides. 1998;19(9):1497-502. doi: 10.1016/s0196-9781(98)00107-7.

Abstract

Pituitary adenylate cyclase activating polypeptide (PACAP), which was isolated from ovine hypothalamic extract, has been shown to have a physiological role in the regulation of insulin or islet functions. In streptozotocin (STZ)-induced diabetic rats, we examined the content of PACAP immunoreactivity and gene expression of three specific receptors. Four weeks after administration of STZ (50 mg/kg), plasma glucose levels increased 3.3-fold, and plasma insulin levels decreased to one-tenth as compared with the control. The content of PACAP immunoreactivity in the pancreas potently increased by 30%, but the content of vasoactive intestinal polypeptide (VIP) immunoreactivity was not changed. In the other tissues, the content of PACAP immunoreactivity did not significantly change except in the hypothalamus, which showed a 10% increment. In the expression level of PACAP/VIP receptors, semi-quantitative RT-PCR analysis revealed that VIP1/PACAP receptor mRNA significantly increased as compared with the other two types of receptors in the pancreas of STZ-induced diabetic rats. These findings suggest that PACAP and VIP1/PACAP receptor might be involved in the pathophysiology of diabetes mellitus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / analysis
  • Body Weight
  • Diabetes Mellitus, Experimental / etiology
  • Diabetes Mellitus, Experimental / metabolism*
  • Hypothalamus
  • Insulin / blood
  • Male
  • Neuropeptides / isolation & purification*
  • Pancreas
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • RNA, Messenger / analysis
  • Radioimmunoassay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
  • Receptors, Pituitary Hormone / genetics
  • Receptors, Pituitary Hormone / isolation & purification*
  • Receptors, Vasoactive Intestinal Peptide / genetics
  • Receptors, Vasoactive Intestinal Peptide / isolation & purification*
  • Receptors, Vasoactive Intestinal Polypeptide, Type I
  • Streptozocin
  • Vasoactive Intestinal Peptide / isolation & purification

Substances

  • Adcyap1 protein, rat
  • Blood Glucose
  • Insulin
  • Neuropeptides
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • RNA, Messenger
  • Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
  • Receptors, Pituitary Hormone
  • Receptors, Vasoactive Intestinal Peptide
  • Receptors, Vasoactive Intestinal Polypeptide, Type I
  • Vasoactive Intestinal Peptide
  • Streptozocin