A species of shark in the family SQUALIDAE, used for its oil (SQUALENE) and as fish meal. It also figures heavily in biological research, especially with reference to its RECTAL GLAND in studies of WATER-ELECTROLYTE BALANCE.
A group of elongate elasmobranchs. Sharks are mostly marine fish, with certain species large and voracious.
A compound tubular gland, located around the eyes and nasal passages in marine animals and birds, the physiology of which figures in water-electrolyte balance. The Pekin duck serves as a common research animal in salt gland studies. A rectal gland or rectal salt gland in the dogfish shark is attached at the junction of the intestine and cloaca and aids the kidneys in removing excess salts from the blood. (Storer, Usinger, Stebbins & Nybakken: General Zoology, 6th ed, p658)
A genus of SHARKS in the family SQUALIDAE, comprised of many different species. They travel in large groups and are bottom dwellers that feed mostly on bony fishes.
An enzyme that in the course of pyrimidine biosynthesis, catalyzes the oxidation of dihydro-orotic acid to orotic acid utilizing oxygen as the electron acceptor. This enzyme is a flavoprotein which contains both FLAVIN-ADENINE DINUCLEOTIDE and FLAVIN MONONUCLEOTIDE as well as iron-sulfur centers. EC 184.108.40.206.
Peptides with the ability to stimulate pigmented cells MELANOCYTES in mammals and MELANOPHORES in lower vertebrates. By stimulating the synthesis and distribution of MELANIN in these pigmented cells, they increase coloration of skin and other tissue. MSHs, derived from pro-opiomelanocortin (POMC), are produced by MELANOTROPHS in the INTERMEDIATE LOBE OF PITUITARY; CORTICOTROPHS in the ANTERIOR LOBE OF PITUITARY, and the hypothalamic neurons in the ARCUATE NUCLEUS OF HYPOTHALAMUS.
An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.
A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.
Derivatives of chondroitin which have a sulfate moiety esterified to the galactosamine moiety of chondroitin. Chondroitin sulfate A, or chondroitin 4-sulfate, and chondroitin sulfate C, or chondroitin 6-sulfate, have the sulfate esterified in the 4- and 6-positions, respectively. Chondroitin sulfate B (beta heparin; DERMATAN SULFATE) is a misnomer and this compound is not a true chondroitin sulfate.
Preparations made from animal tissues or organs (ANIMAL STRUCTURES). They usually contain many components, any one of which may be pharmacologically or physiologically active. Tissue extracts may contain specific, but uncharacterized factors or proteins with specific actions.