Down regulation of the muscarinic cholinergic receptor of the rat prostate following castration
Prostatic secretion is dependent upon the integrity of the endocrine and autonomic nervous systems and is dramatically influenced by muscarinic cholinergic analogs. In this study, the authors have used radioligand receptor binding methods on whole tissue homogenates and slide mounted tissue sections of rat prostate to determine whether androgens regulate the density of muscarinic cholinergic receptors in the prostate. The muscarinic cholinergic receptor binding affinities (Kd) of (/sup 3/H) N-methylscopolamine in prostatic homogenates obtained from intact, castrate, and castrate rats receiving testosterone replacement (castrate + T) were similar (0.07 to 0.10 nM). The muscarinic cholinergic receptor binding capacity decreased 73 per cent following castration. Testosterone administration restored the density of muscarinic cholinergic receptors in castrate rats to intact levels. In order to ensure that the loss of receptor density was not due to a decrease in the epithelial: stromal cell ratio, the number of muscarinic cholinergic receptors per unit area of epithelium was determined in the 3 treatment groups using autoradiography on slide mounted tissue sections. The density of muscarinic cholinergic receptors in a unit area of epithelium was decreased 91 per cent following castration. Testosterone administration restored the density of muscarinic cholinergic receptors in the castrate rats to intact levels. The modulation of neurotransmitter receptors by steroid hormones may be a mechanism by which sex steroids regulate biological responsiveness of target tissues.
- Research Organization:
- Johns Hopkins Hospital, Baltimore, MD
- OSTI ID:
- 5151715
- Journal Information:
- J. Urol.; (United States), Journal Name: J. Urol.; (United States) Vol. 1; ISSN JOURA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AFFINITY
AMINES
AMMONIUM COMPOUNDS
ANDROGENS
ANDROSTANES
ANIMAL TISSUES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BODY
CASTRATION
CHEMICAL BONDS
DRUGS
EPITHELIUM
ESTERS
GLANDS
HOMOGENATES
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
KINETICS
LABELLED COMPOUNDS
LIGANDS
MALE GENITALS
MAMMALS
MEDICINE
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
PROSTATE
QUATERNARY COMPOUNDS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
STEROID HORMONES
STEROIDS
SURGERY
TESTOSTERONE
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES