Pharmacodynamics of a long acting depot preparation of avorelin in patients with prostate cancer. Avorelin Study Group

Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases

Ghrelin and its synthetic analog hexarelin are specific ligands of growth hormone secretagogue (GHS) receptor. GHS have strong growth hormone-releasing effect and other neuroendocrine activities such as stimulatory effects on prolactin and adrenocorticotropic hormone secretion. Recently, several studies have reported other beneficial functions of GHS that are independent of GH. Ghrelin and hexarelin, for examples, have been shown to exert GH-independent cardiovascular activity. Hexarelin has been reported to regulate peroxisome proliferator-activated receptor gamma (PPAR-γ) in macrophages and adipocytes. PPAR-γ is an important regulator of adipogenesis, lipid metabolism, and insulin sensitization. Ghrelin also shows protective effects on beta cells against lipotoxicity through activation of phosphatidylinositol-3 kinase/protein kinase B, c-Jun N-terminal kinase (JNK) inhibition, and nuclear exclusion of forkhead box protein O1. Acylated ghrelin (AG) and unacylated ghrelin (UAG) administration reduces glucose levels and increases insulin-producing beta cell number, and insulin secretion in pancreatectomized rats and in newborn rats treated with streptozotocin, suggesting a possible role of GHS in pancreatic regeneration. Therefore, the discovery of GHS has opened many new perspectives in endocrine, metabolic, and cardiovascular research areas, suggesting the possible therapeutic application in diabetes and diabetic complications especially diabetic cardiomyopathy. Here, we review the physiological roles of ghrelin and hexarelin in the protection and regeneration of beta cells and their roles in the regulation of insulin release, glucose, and fat metabolism and present their potential therapeutic effects in the treatment of diabetes and diabetic-associated heart diseases.

Abarelix for injectable suspension: first-in-class gonadotropin-releasing hormone antagonist for prostate cancer

Abarelix, a gonadotropin-releasing hormone antagonist, with its indication for advanced symptomatic prostate cancer, represents the newest category of hormonal therapy introduced in the past 15 years. Results from Phase II and III clinical trials demonstrate the advantages of abarelix over commonly used luteinizing hormone-releasing hormone (LHRH) agonist therapy: abarelix does not cause a surge in serum testosterone that can precipitate a flare phenomenon or worsening of disease, particularly dangerous for patients with metastatic, symptomatic disease, and produces medical castration more quickly. Abarelix was also demonstrated to promptly and substantially reduce follicle-stimulating hormone levels to lower than LHRH agonist. Study results demonstrate effective anticancer responses during extended exposure to abarelix: improvements in pain score and/or analgesic use, improvements in urinary symptoms (including urinary catheter removal) and complete avoidance of bilateral orchiectomy for patients undergoing at least 12 weeks of treatment. In Phase III clinical trials, abarelix demonstrated a similar overall safety profile when compared with LHRH agonist monotherapy, and a superior safety profile when compared with LHRH agonist plus antiandrogen combination therapy. Abarelix patients experienced a greater incidence of immediate-onset systemic allergic reactions as compared with control arms.

Advancing perspectives on prostate cancer: multihormonal influences in pathogenesis

Nonandrogenic hormones are implicated in the growth and function of the prostate, which is itself an endocrine gland that synthesizes and secretes hormones and growth factors, including follicle-stimulating hormone (FSH) and prostatic inhibin peptide (PIP). Findings of increased FSH concentrations and receptor expression in diseased prostate tissue suggest a role for FSH in prostate cancer growth. Not only does PIP suppress circulating levels of FSH, but it responds to and modulates prostatic FSH, suggesting a close interlinkage of these compounds in controlling both healthy and diseased prostate cells. Other focuses of endocrinologic research include androgen receptors, vitamin D, growth factors (including insulin-like growth factors I and II), and retinoids. Issues such as optimal therapy timing, intermittent administration, and the adoption of a multihormonal approach to the management of prostate cancer remain to be resolved.

Humoral mechanisms in prostate cancer: A role for FSH

The natural history of prostate cancer has long been related to the male hormone testosterone, and treatment has focused on depletion of this androgen to slow or prevent growth of prostate cancer tissue. It has become clear recently, however, that more than androgens influence the progression of prostate cancer, with recent interest focusing on the gonadotropin, follicle-stimulating hormone (FSH). Research of the last decade has found that FSH is produced in and FSH receptors are expressed in the prostate. Investigators have found as well that production of FSH is altered in prostate cancer: FSH levels are increased and receptor production raised in the cancerous prostate. It also has been shown that there are endogenous compounds such as prostatic inhibin peptin that can modulate FSH levels. All of these findings are outlined in this paper, and suggest that FSH may affect the pathogenesis and progression of prostate cancer and that altering FSH production may prove to be an active therapeutic maneuver.

Patient-Clinician choice in palliation of metastatic prostate cancer

Palliation of patients with metastatic prostate cancer is based primarily on offering a form of androgen ablation. Each therapeutic modality has advantages and disadvantages. The decision with regards to the chosen option relies on thorough and open discussion between the treating urologist and the patient. Quality of life issues are increasingly an integral part of the treatment choice opted for. Thus, quality of life questionnaires should be incorporated into future clinical trial assessments and end-points.