Biomaterial Database

Metallothionein and its relationship to the metabolism of dietary zinc in rats. 1976

M P Richards, and R J Cousins

Metallothionein (MTN), a low molecular weight cytoplasmic metalloprotein has previously been implicated in the metabolism of Zn. Experiments were conducted with rats to determine the effect of feeding varying levels of dietary Zn for short periods on the increase or decrease in MTN-bound Zn. The results indicated that MTN-Zn in both liver and intestinal mucosal cytosol responded rapidly to an altered dietary Zn level and that serum Zn was directly related to the appearance of MTN. 65Zn absorption also responded rapidly to a change in dietary Zn and was inversely correlated with intestinal mucosal MTN-Zn. Hepatic 65Zn uptake appeared to be directly correlated with liver MTN-Zn. A 24 hour fast increased MTN-Zn in rats fed two different levels of Zn except in those rats that were previously treated with actinomycin D. The antibiotic, which blocks DNA-dependent RNA synthesis, appeared to block Zn uptake from blood to the liver. These findings offer support for the involvement of MTN in zinc metabolism.

UI	MeSH Term	Description	Entries
D007408	Intestinal Absorption	Uptake of substances through the lining of the INTESTINES.	Absorption, Intestinal
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D007421	Intestine, Small	The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.	Small Intestine,Intestines, Small,Small Intestines
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008667	Metalloproteins	Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)	Metalloprotein
D008668	Metallothionein	A low-molecular-weight (approx. 10 kD) protein occurring in the cytoplasm of kidney cortex and liver. It is rich in cysteinyl residues and contains no aromatic amino acids. Metallothionein shows high affinity for bivalent heavy metals.	Isometallothionein,Metallothionein A,Metallothionein B,Metallothionein I,Metallothionein II,Metallothionein IIA
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D003609	Dactinomycin	A compound composed of a two CYCLIC PEPTIDES attached to a phenoxazine that is derived from STREPTOMYCES parvullus. It binds to DNA and inhibits RNA synthesis (transcription), with chain elongation more sensitive than initiation, termination, or release. As a result of impaired mRNA production, protein synthesis also declines after dactinomycin therapy. (From AMA Drug Evaluations Annual, 1993, p2015)	Actinomycin,Actinomycin D,Meractinomycin,Cosmegen,Cosmegen Lyovac,Lyovac-Cosmegen,Lyovac Cosmegen,Lyovac, Cosmegen,LyovacCosmegen