Role of micro tubules and microfilaments in polypeptide and steroid hormone secretion: a review

Abstract

The important part played by the cytoskeleton m the dynamic process of polypeptide and steroid hormone secretion has been examined. Certain specific endocrine tissues have been chosen to analyse the information available regarding hormone secretion. For example, for polypeptide hormones the anterior lobe of the pituitary and the islets of Langcrhans have been discussed whereas for the steroid hormones, the ovaries and the adrenals have been chosen for discussion.

Evidence suggesting the involvement of exocytosis in the secretion of the two types of hormones has been discussed. Most of the data regarding the role of the cytoskeleton in hormone secretion has so far been obtained by employing drugs known to affect either microfilarnents or microtubules-thereby studying the effects of pharmacological doses of the drugs on hormonal secretion. At these high doses, the specIficity of the drug effects is questionable. On the other hand, however, a few investigators have examined the biochemistry of the cytoskeleton during hormone secretion. Sensitive methods have been standardised to study the equilibrium between soluble and poJymensed tubulin or actin pools, the assembly of tubulin into micro tubules and the GTPase activity of tubulin