CHAPTER 15 - The Adrenal Cortex

Cholesterol, an essential and versatile lipid, is the precursor substrate for the biosynthesis of steroid hormones, and a key structural and functional component of organelle membranes in eukaryotic cells. Consequently, the framework of steroidogenesis across main steroidogenic cell types is built around cholesterol, including its cellular uptake, mobilization from intracellular storage, and finally, its transport to the mitochondria where steroidogenesis begins. This setup, which is controlled by different trophic hormones in their respective target tissues, allows steroidogenic cells to meet their steroidogenic need of cholesterol effectively without impinging on the basic need for organelle membranes and their functions. However, our understanding of the basal steroidogenesis (i.e., independent of trophic hormone stimulation), which is a cell-intrinsic trait, remains poor. Particularly, the role that cholesterol itself plays in the regulation of steroidogenic factors and events in steroid hormone-producing cells remains largely unexplored. This is likely because of challenges in selectively targeting the steroidogenic intracellular cholesterol pool in studies. New evidence suggests that cholesterol plays a role in steroidogenesis. These new findings have created new opportunities to advance our understanding in this field. In this book chapter, we will provide a cholesterol-centric view on steroidogenesis and emphasize the importance of the interplay between cholesterol and the mitochondria in steroidogenic cells. Moreover, we will discuss a novel mitochondrial player, prohibitin-1, in this context. The overall goal is to provide a stimulating perspective on cholesterol as an important regulator of steroidogenesis (i.e., more than just a substrate for steroid hormones) and present the mitochondria as a potential cell-intrinsic factor in regulating steroidogenic cholesterol homeostasis.

Adrenal insufficiency can arise from a primary adrenal disorder, secondary to adrenocorticotropic hormone deficiency, or by suppression of adrenocorticotropic hormone by exogenous glucocorticoid or opioid medications. Hallmark clinical features are unintentional weight loss, anorexia, postural hypotension, profound fatigue, muscle and abdominal pain, and hyponatraemia. Additionally, patients with primary adrenal insufficiency usually develop skin hyperpigmentation and crave salt. Diagnosis of adrenal insufficiency is usually delayed because the initial presentation is often non-specific; physician awareness must be improved to avoid adrenal crisis. Despite state-of-the-art steroid replacement therapy, reduced quality of life and work capacity, and increased mortality is reported in patients with primary or secondary adrenal insufficiency. Active and repeated patient education on managing adrenal insufficiency, including advice on how to increase medication during intercurrent illness, medical or dental procedures, and profound stress, is required to prevent adrenal crisis, which occurs in about 50% of patients with adrenal insufficiency after diagnosis. It is good practice for physicians to provide patients with a steroid card, parenteral hydrocortisone, and training for parenteral hydrocortisone administration, in case of vomiting or severe illness. New modes of glucocorticoid delivery could improve the quality of life in some patients with adrenal insufficiency, and further advances in oral and parenteral therapy will probably emerge in the next few years.

Cushing's disease (CD) is the most common cause of endogenous Cushing's syndrome. Transsphenoidal surgery (TSS) is the first choice of treatment. Predicting prognosis after treatment can benefit further strategies of management, but currently there is no convenient predictor. This study aims to investigate characteristic changes after treatment and to identify potential prognostic predictors.

We retrospectively studied the records of CD patients presenting to the National Taiwan University Hospital, Taipei, Taiwan between 1992 and 2011. They were categorized according to treatment response. Clinical features and examination findings were compared between groups.

Forty-one patients with CD were included. The follow-up time was 0.26–19.3 years. The time interval between the onset of symptoms and diagnosis was 2.1–120.0 months. The initial remission rate of CD after the first treatment was 82.9%. Mean body mass index (BMI) was 27.4 kg/m² before treatment and 26.0 kg/m² 3 months after treatment. The patients in remission had a greater decrease in BMI after treatment and lower dehydroepiandrosterone sulfate (DHEAS) levels before treatment, compared with the recurrent group (both p < 0.05). Adrenocorticotropic hormone (ACTH) levels before treatment showed a significant positive correlation with recurrent diseases (p < 0.05).

A larger decrease in BMI after treatment and lower DHEAS levels before treatment were noted for the patients who stayed in CD remission. Higher ACTH levels before treatment predicted a recurrence of CD. These are potentially simple and practical predictors of prognosis.

Corticosteroids have been used in combination with chemotherapy for the treatment of metastatic castration-resistant prostate cancer (mCRPC) for more than three decades, particularly to treat pain, inflammation, and edema. More recently, they have been used in combination with hormonal agents. The importance of corticosteroids in mCRPC is due to their ability to manage adverse effects, reduce symptoms, and improve patients' quality of life. The appropriate selection of available options in mCRPC should be based on careful consideration of a patient's profile and comorbidities. This review provides an overview of the role of corticosteroids in treating mCRPC for the practicing urologist.