Tissue culture in endocrine research: perspectives, pitfalls, and potentials

Primary tissue cultures of benign and malignant human thyroid tumors: effect of TSH

Many thyroid carcinomas seem to be dependent upon the thyroid growth-promoting properties of the thyroid stimulating hormone (TSH). The purpose of the present investigation was to compare the in vitro effect of TSH on tissue cultures derived from malignant and benign thyroid tumors. The results indicate that TSH can affect the morphology and protein synthesis of primary tissue cultures derived from benign and malignant thyroid tumors differently. The addition of TSH to cultures derived from benign tumors resulted in a reorganization of follicle-like structures of the monolayer and in a reduction of protein synthesis. In contrast to this, monolayers derived from carcinomas of the thyroid were not able to reorganize and their protein synthesis was not inhibited in the presence of TSH. For a better understanding of TSH suppressive therapy, we suggest testing the influence of TSH on a large number of tissue cultures derived from benign and malignant tumors of the thyroid.

Use of semipermeable polyurethane hollow fibers for pituitary organ culture

A new model for organ culture of endocrine tissue is described. Rat anterior pituitary fragments were cultured for 4 wk within semipermeable polyurethane isocyanate hollow fibers. Growth hormone and prolactin, two of the anterior pituitary hormones, were released into the medium during the entire culture period. Electron microscopy of the pituitary fragments after 2 wk in culture showed a rim of viable tissue in all specimens examined. Individual cells, from this outer rim, exhibited excellent organelle preservation and numerous secretory granules. Experiments involving potassium depolarization and 10(-6) M dopamine provided evidence for the normal responsiveness of the cultured pituitary tissue to both stimulatory and inhibitory factors. These studies illustrate the potential utility of the described organ culture system for further investigations of endocrine physiology.

Physiological and pathological effects of steroids on the function of the adrenal cortex

The adrenal cortex is the site of the synthesis of steroid hormones such as the glucocorticoid cortisol and the mineralocorticoid aldosterone. The pathway of biosynthesis of these steroids from cholesterol involves a sequence of transformations using cytochrome P-450 enzymes which varies within the adrenal cortex as a result of the differential localization of enzymes within the zones. The hypothesis presented here is that as a result of the arrangement of the vasculature in the adrenal gland, high concentrations of steroids may be expected to accumulate and may have autoregulating effects. These may include the following: (1) the normal morphological and functional zonation of the adrenal cortex may be regulated by gradients of steroids in the adrenal cortex; (2) destruction of cytochrome P-450 enzymes on interaction with certain steroids which act as pseudosubstrates may form part of the pathogenesis of some steroidogenic enzyme deficiencies. Under normal conditions, the individual cytochrome P-450s are not rate-limiting for steroidogenesis. Under some pathological conditions, individual cytochrome P-450 enzyme activities may become rate-limiting, with consequent overproduction of precursor steroids, leading to mineralocorticoid or androgen excess.

The pathology of adrenocortical neoplasia: a correlated structural and functional approach to the diagnosis of malignant disease

The structural and functional characteristics of nine functioning adrenocortical tumors (four adenomas and five carcinomas) causing Cushing's syndrome or virilization were studied. All tumors that we considered to show histologic evidence of malignant disease and that subsequently metastasized or recurred also showed in cell culture at least one significant functional or behavioral difference from benign tumors. No single defect was common to all carcinomas, but predominant changes included secretion of precursor steroids, such as 11-deoxycortisol (S) and a blunted or absent response to ACTH. All adenomase examined were normal in these respects in comparison with nondiseased cortical cells in culture. In carcinomas whose functions deviated only minimally from normal the presence of highly differentiated ultrastructural characteristics did not, however, confer a better prognosis.