AN IN VIVO BIOASSAY FOR PROLACTIN-RELEASING FACTOR

垂体前叶激素催乳素（PRL）参与 生殖和非生殖过程。 高催乳素血症 是一种普遍的垂体功能紊乱， 女性不孕和男性阳痿的风险。 PRL是唯一的 垂体前叶激素，其分泌受到紧张性抑制， 多巴胺被认为是 PRL分泌。 有证据表明催乳素的存在- 释放因子（PRF），但其身份仍然未知。 使用 一个垂体前叶细胞灌注系统，我们最近发现， 垂体后叶含有一种强有力的PRF， 快速、特异性、浓度依赖性刺激 PRL释放 PRF是一种小肽，其不同于已知的肽。 催乳素促分泌素。 我们目前正在从牛中分离PRF 后垂体 到目前为止， 垂体PRF仅依赖于体外生物测定。 的目标 本研究旨在建立一种估算PRF的体内模型 活性，与体外生物测定相结合，将 在我们的净化工作中使用。 这项建议的具体目标是： 1. 建立一种适用于PRF的提取程序 用于体内给药。 最初，大鼠和牛的后部 垂体将用乙酸提取，通过5 K过滤 道尔顿膜，并用过甲酸处理， 加压素和催产素。 部分纯化的 在体内给药之前，将在体外验证提取物。 2. 确定体内生物测定的最佳条件。 给药途径和动物的内分泌状态 将进行测试，以确定最敏感的条件。 3. 目的：研究PRF在体内的活性特征。 的 剂量依赖性和重复注射 将检查提取物。 体内生物测定法的发展将有助于 PRF隔离。 一旦已知PRF的结构， 治疗的替代治疗方法 可能会出现高泌乳素血症和PRF拮抗剂。

The anterior pituitary hormone prolactin (PRL) is involved in reproductive and nonreproductive processes. Hyperprolactinemia is a prevalent disorder of pituitary function, and a common cause of infertility in women and impotence in men. PRL is the only anterior pituitary hormone whose secretion is tonically inhibited, and dopamine is accepted as the major physiological inhibitor of PRL secretion. Evidence suggests the existence of a prolactin- releasing factor (PRF), but its identity remains unknown. Using an anterior pituitary cell perifusion system, we recently showed that the posterior pituitary contains a potent PRF which causes a rapid, hormone-specific, concentration-dependent stimulation of PRL release. PRF is a small peptide which is distinct from known PRL secretagogues. We are presently isolating PRF from bovine posterior pituitaries. Thus far, the characterization of posterior pituitary PRF has relied on an in vitro bioassay only. The goal of this proposal is to establish an in vivo model for estimating PRF activity, which in conjunction with the in vitro bioassay, will be used throughout our purification efforts. The specific aims of this proposal are: 1. To establish an extraction procedure for PRF which is suitable for in vivo administration. Initially, rat and bovine posterior pituitaries will be extracted with acetic acid, filtered through 5K dalton membranes, and treated with performic acid to inactivate vasopressin and oxytocin. PRF activity in partially purified extracts will be verified in vitro prior to in vivo administration. 2. To identify the optimal conditions for the in vivo bioassay. The route of administration and the endocrine state of the animal will be tested to determine the most sensitive conditions. 3. To determine the characteristics of PRF activity in vivo. The dose-dependency and the effects of repeated injections of the extracts will be examined. The development of an in vivo bioassay will facilitate the isolation of PRF. Once the structure of PRF is known, alternative therapeutic approaches for the treatment of hyperprolactinemia with PRF antagonists may be developed.