The effect of oleic acid on the secretion of thyrotrophin and growth hormone by cultured rat anterior pituitary cells.

Elevation of non-esterified fatty acids (NEFA) in vivo is associated with abnormal control of TSH. To determine whether TSH secretion is directly inhibited by NEFA, as has been reported for GH, cultured rat anterior pituitary cells were exposed for 20 h to oleic acid in medium containing 7.7×10 -5 mol/l bovine serum albumin (BSA). In a molar ratio with albumin of 1.2 (total oleic acid 9×10 -5 mol/l), or greater, oleic acid inhibited basal GH secretion (maximum inhibition to 40% of control) while basal TSH was less affected, a ratio of 3 (2.3×10 -4 mol/l oleic acid) or greater causing a smaller degree of inhibition (maximum inhibition to 80% of control)