Direct Radioligand Measurement of Oxytocin Receptors in Anterior Pituitary Gland

Autor: F.A. Antoni, S.E. Chadio
Rok vydání: 1991
Předmět:
DOI: 10.1016/b978-0-12-185259-7.50021-1
Popis: Publisher Summary This chapter presents methods for direct radioligand measurement of oxytocin receptors in anterior pituitary gland. The cellular actions of oxytocin are mediated by binding to cell surface receptors on target cells. In addition to its well-defined peripheral actions in the uterus and the mammary gland, oxytocin may also function as a hypothalamic releasing hormone for prolactin, a central nervous system neurotransmitter involved in reproductive functions, and a paracrine hormone in the gonads. At present, all methods for measuring oxytocin receptors are based on the binding of radioligands. The most widely used probe is tritium-labeled oxytocin. The classic receptor criteria of reversibility, saturability, and high affinity can be readily tested using established procedures. In the case of the adenohypophyseal oxytocin receptors, the association of the radioligand to membrane suspensions reaches a steady state by 60 min. Binding saturation studies show that the specific component of the binding is saturable. No appreciable effect on the binding of OTA or on the potency of oxytocin to displace OTA is observed, indicating that the effects of manipulating G proteins are minimal compared with the changes brought about by altering Mg 2+ .
Databáze: OpenAIRE