MEDICAL PHYSIOLOGY

Detailed explanation-1: -Other lipid-soluble hormones that are not steroid hormones, such as vitamin D and thyroxine, have receptors located in the nucleus. The hormones diffuse across both the plasma membrane and the nuclear envelope, then bind to receptors in the nucleus.

Detailed explanation-2: -Steroid hormones are the most common circulating lipid-soluble hormones. Steroid hormones include: testosterone, estrogens, progesterone, aldosterone and cortisol.

Detailed explanation-3: -Hormone Action Hormones fall into two general groups-steroid and nonsteroid hormones. Each type of hormone acts on a target cell in a different way. Steroid hormones are produced from a lipid called cholesterol. Nonsteroid hormones include proteins, small peptides, and modified amino acids.

Detailed explanation-4: -Many hormones are composed of polypeptides-such as thyroid-stimulating hormones, follicle-stimulating hormones, luteinizing hormones, and insulin. These molecules are not lipid-soluble and therefore cannot diffuse through cell membranes.