The secretion of hypothalamic, pituitary, and target tissue hormones is under tight regulatory control by a series of feedback and feed- forward loops. This complexity can be demonstrated using the growth hormone (GH) regulatory system as an example. The stimulatory substance growth hormone releasing hormone (GHRH) and the inhibitory substance somatostatin (SS) both products of the hypothalamus, control pituitary GH secretion. Somatostatin is also called growth hormone-inhibiting hormone (GHIH). Under the influence of GHRH, growth hormone is released into the systemic circulation, causing the target tissue to secrete insulin-like growth factor-1, IGF-1. Growth hormone also has other more direct metabolic effects; it is both hyperglycemic and lipolytic. The principal source of systemic IGF-1 is the liver, although most other tissues secrete and contribute to systemic IGF-1. Liver IGF-1 is considered to be the principal regulator of tissue growth. In particular, the IGF-1 secreted by the liver is believed to synchronize growth throughout the body, resulting in a homeostatic balance of tissue size and mass. IGF-1 secreted by peripheral tissues is generally considered to be autocrine or paracrine in its biological action.
If you want to know how to inject steroids , the first thing you need to know is how to prepare for the injection. You know you need to stick it into the muscle tissue, and we’ll go into the specifics of that later on, but there’s more to it than that. There are eight specific steps you need to follow when injecting anabolic steroids, and while that may sound like a lot the whole process shouldn’t take but a minute. Failure to follow these eight remarkably simple steps can result in complications such as infections or simply very uncomfortable injections, and an unnecessarily sore injected area.
The past few years have witnessed the emergence of steroid hormones as the wonder molecules which generate as much discussion in the scientific literature as they do in a typical living room. This transition has been a result of the tremendous public and scientific interest in the normal functioning of the hor mones as well their suggested involvement in several clinical conditions. In the recent past, notable scientific and technological advances have been made in the areas of contraception and regulation of fertility. Steroid receptors are the indis pensable mediators of hormonal responses and are complex protein molecules which appear to exist in association with other, yet undefined, proteins and/or factors. Receptors for vitamin D, retinoic acid and the thyroid hormones share structural similarities with steroid receptors, and the roster of this superfamily is still expanding. While our knowledge of the diversity and magnitude of steroid effects has advanced, the precise mode of steroid hormone action has alluded investigators. This volume brings together an international team of prominent investigators who discuss their most recent work on the basic and clinical aspects of steroid/nuclear receptors. The contributions represent updated versions of the invited presentations made at The Second Meadow Brook Conference on Steroid Receptors in Health and Disease. I am grateful to my colleagues on the Scientific Committee: Etienne Baulieu, Jack Gorski, Benita Katzenellenbogen, David Toft and James WittJiff, who provided the vision and guidance in formulating an out standing program.