Tissue Distribution of PACAP as Determined by RIA: Highly Abundant in the Rat Brain and Testes

Abstract

A heterologous RIA method for pituitary adenylate cyclase activating polypeptide with 38 residues (PACAP38) and a homologous RIA method for a shorter form of PACAP with 27 residues (PACAP27) were established to determine PACAP content in central and peripheral tissues in rats. The highest concentration of radioimmunoassayable PACAP38 was found in the hypothalamus, but other brain regions also contained considerable amounts of PACAP38. PACAP38 concentration in the posterior pituitary was comparable with that in the extrahypothalamic brain, but its concentration in the anterior pituitary was very low. Unexpectedly, the testis contained a high abundance of PACAP38, and the total amount of PACAP in both testes exceeded its content in the whole brain. Reverse phase HPLC suggested that the major testicular PACAP38 immunoreactivity represents PACAP38. Among peripheral tissues, adrenal gland contained the second highest concentration of PACAP. Smaller amounts of PACAP were widely distributed in the digestive tract and other peripheral tissues. The concentration of PACAP in stomach, duodenum and jejunum appeared to be greater than in other portions of the gut. In all tissues, PACAP27 represented only a minor portion of total PACAP immunoreactivity.

Pituitary adenylate cyclase-activating polypeptide is an autocrine inhibitor of mitosis in cultured cortical precursor cells

“…Moreover, antagonist stimulation was reversed by coincubation with PACAP, confirming specificity. Similar blockade of endogenous PACAP activity was observed with peptide-neutralizing antibody (12) (Fig. 6f ).…”

“…The 38-amino acid peptide pituitary adenylate cyclaseactivating polypeptide (PACAP) (10), a new member of the vasoactive intestinal peptide (VIP)͞secretin͞glucagon family (11)(12)(13), is expressed in brain as early as embryonic day 14 (E14). Although peptide levels in whole brain increase 5-fold by birth with little change thereafter, mature expression is mainly restricted to the diencephalon and limbic structures, reflecting PACAP's role in hypothalamic-pituitary regulation (10,11).…”

“…Freshly dissected tissue was collected, frozen on dry ice, and stored at Ϫ80ЊC until assay was performed by Dr. A. Arimura (12).…”

Pituitary Adenylate Cyclase‐Activating Polypeptide Causes Ca2+ Release from Ryanodine/Caffeine Stores Through a Novel Pathway Independent of Both Inositol Trisphosphates and Cyclic AMP in Bovine Adrenal Medullary Cells

“…This view has been supported by the following findings: (a) the adrenal gland contains the second highest concentration of PA-CAP among peripheral organs (Arimura et al, 1991); (b) PACAP-like immunoreactivity is found in the nerve endings innervating the adrenal medulla, as well as in adrenal medullary cells (Tabarin et al, 1994;Frödin et al, 1995;Shiotani et al, 1995); (c) the adrenal medullary cells express PACAP type-I receptor (PACAP-preferring receptor) mRNA (Spengler et al, 1993); and (d) PACAP increases catecholamine release, intracellular cyclic AMP (cAMP), inositol trisphosphates (1P 3), and the intracellular Ca 2~concentra-tion ([Ca2~I~) (Watanabe et al, 1992;Isobe et al, 1993;Chowdhury et al, 1994;Guo and Wakade, 1994;Tanaka et al, 1996). PACAP type-I receptors are seven-helix receptors, and five splicing variants with insertions at the C-terminal end of the third intracellular ioop are reported (PACAP-R, PACAP-R-hip, PACAP-R-hop1, PACAP-R-hop2, PACAP-R-hip-hopl) (Spengler et al, 1993).…”

Photoaffinity Labeling Analysis of the Interaction of Pituitary Adenylate‐Cyclase‐Activating Polypeptide (PACAP) with the PACAP Type I Receptor

“…The peptide belongs to the secretin/glucagon/vasoactive intestinal peptide (VIP) family and shows the highest similarity (68%) to VIP. PACAP is widely distributed in mammalians with the highest concentration in the central nervous system (Koves et al, 1990;Arimura et al, 1991). It is a hypophysiotropic hormone and also functions as neurotransmitter, neuromodulator, and neurotrophic factor in the central nervous system (for details see the following reviews : Arimura et al, 1994;Arimura and Shioda, 1995).…”