Thymopoietin and thymopentin enhance the levels of ACTH, beta-endorphin and beta-lipotropin from rat pituitary cells in vitro.

Thymopoietin and thymopentin are well characterized polypeptides influencing immunoregulation by several mechanisms. Proposed as a therapy in diseases with major immune abnormalities such as rheumatoid arthritis, thymopentin improved within 2 weeks some clinical parameters as pain and joint swelling. The hypothesis that this spectacular effect could be mediated through interactions with anti-inflammatory (ACTH) and pain relieving (beta-endorphin) hormones producing cells was tested on the rat isolated pituitary cell model. Thymopentin and thymopoietin can enhance in vitro the levels of ACTH, beta-endorphin and beta-lipotropin in a time- and dose-dependent fashion for physiological concentrations ranging from 10(-12) to 10(-8) mol/l. The action on pituitary cells was restricted to those molecules as no changes occurred in LH, FSH, GH, TSH and PRL levels, after otherwise identical experimental conditions.