Recent Progress in Hormone Research, Volume 23 is a collection of papers presented at the 1966 Laurentian Hormone Conference, held at Mont Tremblant, Quebec, Canada. This conference explores four major areas of research, including thyroid physiology, thyroid hormones, contemporary developments in peptide hormone chemistry and biochemistry, and special studies of insulin, particularly in man. This book is organized into four parts encompassing 14 chapters. Part I deal with the factors controlling thyroid stimulation and special studies of the mode of action of thyroid hormones, including antithyroid drugs. Part II describes the mode of action of steroid hormones and hormonal steroids based on the effects on normal and neoplastic tissues. This part also looks into a definitive segment of research in endocrinology with the metabolism of the steroid hormones in vivo and in vitro. The discussion of an important clinical condition involving adrenocortical steroid production is given in the chapter concerned with congenital adrenal hyperplasia. Parts III and IV explore the synthesis of peptide hormones and insulin. These parts also tackle the gastrointestinal hormone biochemistry, the detection of at least two insulin-like activities in human serum, and the particular control of insulin activity in man. This book is directed primarily toward endocrinologists.