Secretion of catecholamines, ascorbic acid, progesterone and corticosterone by in-vitro superfusion from the adrenal of the Mongolian gerbil (Meriones Unguiculatus): effects of confinement stress.

Epinephrine (E) and corticosterone (CS) levels in the superfusate of adrenals of Mongolian gerbils superfused at either 4 degrees or 36 degrees C rapidly declined within the first 5-20 min of superfusion. While the concentrations in superfusate of adrenals superfused at 4 degrees C remained very low until the end of superfusion, levels were significantly higher when adrenals were superfused at 36 degrees C. These results indicate that the amounts of E (except during the first 15-20 min of superfusion) and of CS released by adrenals superfused at 36 degrees C were due to an active, temperature- dependent release. Confinement stress (6 hr) significantly reduced E release at 20-75 min of superfusion but had no effect on the in-vitro secretion of norepinephrine (NE) or ascorbic acid (ASA). On the other hand, the in-vitro secretion of progesterone (P) and CS was significantly increased by confinement stress at 5-120 min of superfusion. Application of this stress factor had no significant effect on adrenal content of NE, E or ASA but increased adrenal P and CS concentrations. In addition to the widely used parameters such as plasma and adrenal tissue levels, the in-vitro approach, reflecting in part the in-vivo activity of the adrenal cortex, seems very suitable to monitor changes in steroid secretion after either in-vivo or in-vitro application of ACTH. Furthermore, the effects of application of different stress factors on in-vitro secretion and possible alterations in biosynthetic pathways can be studied over several hours in the absence of central nervous system and metabolic influences.