1. [Somatotropin: endocrinological aspects].
- Author
-
Suurd GJ, van Dijk AJ, van der Burgt GM, and Brand A
- Subjects
- Animals, Dose-Response Relationship, Drug, Female, Growth Hormone administration & dosage, Growth Hormone-Releasing Hormone physiology, Lactation drug effects, Pregnancy, Receptors, Somatotropin physiology, Somatomedins biosynthesis, Somatostatin physiology, Cattle physiology, Growth Hormone metabolism, Pituitary Gland metabolism
- Abstract
Bovine somatotropin (BST) is a polypeptide hormone produced by the pituitary gland. Its release is regulated by hypothalamic hormones such as the Growth Hormone Releasing Factor (GRF) and the Somatotropin Release Inhibiting Factor (SRIF). Unlike somatotropin, GRF en SRIF are not species-specific. Somatotropin is released into the blood, and then bound to receptors which are present in various tissues but not in those of the mammary gland. Binding of somatotropin to receptors of hepatocytes results in the synthesis of somatomedins which are mediators of somatotropin. Receptors for somatomedins were recently found to be present in mammary gland tissue. The release of somatotropin is pulsatile and is influenced by steroids, genetic factors, nutrition and pregnancy. The effect of BST is dependent on its average concentration in the plasma and not on a particular pattern in this concentration. The effect of administration of BST prior to peak lactation is variable, but subsequently continuous to be positive. It therefore is advisable to start treatment after day 90. In the future, administration of recombinant-BST will be performed through slow-release preparations.
- Published
- 1988