LIGANDIN CONCENTRATIONS IN THE STEROIDOGENIC TISSUES OF THE RAT DURING DEVELOPMENT

Ligandin, a ubiquitous multifunctional cytoplasmic protein which exhibits glutathione S-transferase, glutathione peroxidase and .DELTA.5-3-ketosteroid isomerase activities and binds to cortisol metabolites, is present in relatively high concentrations in gonadal and adrenal tissues. In contrast to hepatic ligandin, little is known about the ontogeny of ligandin in steroid-synthesizing tissues. The intracellular concentrations of ligandin are reported as well as the serum concentrations of testosterone and progesterone measured by radioimmunoassay at different stages of development in the rat. Ligandin levels in testis, ovary and adrenal tissue were relatively high soon after birth, decreased by day 9 and increased rapidly during puberty to reach adult levels. These changes appeared to be paralleled by changes in the circulating levels of testosterone and progesterone. In contrast, ligandin levels in non-steroidogenically active tissues, such as liver and kidney, were low at birth and rose progessively to reach adult levels. Hepatic ligandin concentration could be increased at all stages of development by phenobarbital induction but no induction occurred in the endocrine tissues.