Shivers B D, Görcs T J, Gottschall P E, Arimura A
U.S.-Japan Biomedical Research Laboratories, Tulane University, Belle Chasse, Louisiana 70037.
Endocrinology. 1991 Jun;128(6):3055-65. doi: 10.1210/endo-128-6-3055.
Two bioactive products of pituitary adenylate cyclase-activating polypeptide (PACAP) prohormone have been isolated from ovine hypothalamus: PACAP38 with 38 residues and PACAP27 corresponding to the N-terminal 27 residues of PACAP38. Immunocytochemical and RIA results support the existence of PACAP in the rat brain, posterior pituitary, and various peripheral tissues. Furthermore, high affinity PACAP-binding sites have been detected in the rat brain, anterior pituitary, and cultured astrocytes which differ from those in lung, liver, and cultured mouse splenocytes. In the present study additional rat tissues were examined to elucidate the location and characteristics of PACAP-binding sites using [125I] PACAP27 with conventional methods of receptor autoradiography and RRA. Binding specificity was established by displacement with unlabeled PACAP27 or a related peptide, vasoactive intestinal polypeptide (VIP). PACAP27-binding sites were localized autoradiographically in the testis, epididymis, adrenal gland, lung, liver, prostate gland, and seminal vesicle; binding sites were not detected in the heart, kidney, or thymus. In the testis and epididymis, a PACAP27-binding site was localized on germinal cells and in the adrenal gland on medullary chromaffin cells. Excess VIP did not displace PACAP27 binding localized in these three tissues. A site with a greater affinity for PACAP27 than for VIP was detected in adrenal gland and epididymis, characteristic of a site recognized previously in hypothalamus, anterior pituitary, and cultured astrocytes. The PACAP-specific site was more abundant in these tissues than a second site to which PACAP27 and VIP bound with similar affinities. Accordingly, the first site has been named type I. In lung, liver, prostate, and seminal vesicle, VIP displaced PACAP27 binding localized autoradiographically. Lung and liver contained an abundant site to which PACAP27 and VIP bound with similar affinities. This binding site, measured previously in lung, liver, and cultured splenocytes, may be shared by PACAP and VIP and has been named type II. Taken together, these data support the existence of two high affinity binding sites for PACAP with different tissue distribution.
从绵羊下丘脑分离出了垂体腺苷酸环化酶激活多肽（PACAP）前体激素的两种生物活性产物：含38个氨基酸残基的PACAP38以及对应于PACAP38 N端27个氨基酸残基的PACAP27。免疫细胞化学和放射免疫分析结果支持PACAP存在于大鼠脑、垂体后叶及多种外周组织中。此外，在大鼠脑、垂体前叶及培养的星形胶质细胞中检测到了高亲和力的PACAP结合位点，这些位点与肺、肝及培养的小鼠脾细胞中的不同。在本研究中，使用[125I]PACAP27并采用受体放射自显影和放射受体分析的常规方法，对更多的大鼠组织进行了检测，以阐明PACAP结合位点的定位和特征。通过用未标记的PACAP27或相关肽血管活性肠肽（VIP）进行置换来确定结合特异性。通过放射自显影法在睾丸、附睾、肾上腺、肺、肝、前列腺和精囊中定位了PACAP27结合位点；在心脏、肾脏或胸腺中未检测到结合位点。在睾丸和附睾中，PACAP27结合位点定位于生殖细胞，在肾上腺中定位于髓质嗜铬细胞。过量的VIP不能置换这三种组织中定位的PACAP27结合。在肾上腺和附睾中检测到一个对PACAP27的亲和力高于对VIP的亲和力的位点，这是先前在下丘脑、垂体前叶和培养的星形胶质细胞中识别出的位点的特征。这些组织中PACAP特异性位点比PACAP27和VIP以相似亲和力结合的第二个位点更丰富。因此，第一个位点被命名为I型。在肺、肝、前列腺和精囊中，VIP置换了放射自显影定位的PACAP27结合。肺和肝含有一个丰富的位点，PACAP27和VIP以相似的亲和力与之结合。这个先前在肺、肝和培养的脾细胞中检测到的结合位点可能为PACAP和VIP所共有，并被命名为II型。综上所述，这些数据支持存在两种具有不同组织分布的PACAP高亲和力结合位点。
