Hormones are chemical messengers that are synthesized in the endocrine glands. They are derived from various biochemical substances like amino acids, cholesterol, and phospholipids. Proteins are not considered as precursors of hormones as they are large macromolecules that are synthesized by the ribosomes in the cytoplasm. Hormones can be classified into two types based on their solubility, i.e., lipid-soluble and water-soluble hormones. Lipid-soluble hormones are derived from cholesterol, whereas water-soluble hormones are derived from amino acids or peptides.

Iodine is an essential mineral that plays a crucial role in the functioning of the thyroid gland, which regulates the body's metabolism. Iodine deficiency can lead to thyroid disorders, including goiter, cretinism, and hypothyroidism. Iodized salt contains a small amount of iodine, which helps to maintain adequate levels of iodine in the body and prevent iodine deficiency. By consuming iodized salt, individuals can prevent the development of thyroid disorders and maintain optimal thyroid function.

Adrenaline, also known as epinephrine, is a hormone that is produced by the adrenal glands. It is released into the bloodstream in response to stress, fear, or excitement. Adrenaline acts on various organs in the body, including the heart, by increasing the heartbeat and the force of contractions. This results in an increase in blood pressure and blood flow to the muscles, preparing the body for physical activity. Adrenaline also produces a feeling of excitement or arousal, which is why it is often referred to as the "fight or flight" hormone.

Oxytocin is a hormone produced by the hypothalamus and released by the posterior pituitary gland. It plays a crucial role in childbirth and lactation by stimulating the contraction of the uterus and the release of milk from the mammary gland. When a baby suckles at the breast, it triggers nerve impulses that travel to the hypothalamus, which then signals the pituitary gland to release oxytocin. The oxytocin causes the muscles around the milk glands to contract, pushing the milk down the ducts and out of the nipple. This process is known as the let-down reflex.

Parathormone is a hormone secreted by the parathyroid gland in response to low levels of calcium in the blood. Its primary function is to regulate calcium and phosphate metabolism in the body. When the blood calcium level is low, parathormone increases the release of calcium from bones into the blood, and promotes the absorption of calcium from the small intestine and kidneys. Parathormone also reduces the excretion of calcium by the kidneys, thus conserving calcium in the body. As a result, parathormone increases the blood calcium level, which is important for normal functioning of nerves, muscles, and bones.

Somatotropin, also known as growth hormone (GH), is a peptide hormone that is secreted by the pituitary gland. It plays a vital role in promoting growth and development in humans, especially during childhood and adolescence. In addition to its effects on growth, somatotropin also has metabolic effects, such as promoting the breakdown of fat and stimulating protein synthesis. It is also involved in the regulation of glucose levels in the blood. Somatotropin is typically released in pulses throughout the day, with the highest levels occurring during sleep.

Estrogen is a female sex hormone that plays an important role in the development and maintenance of female reproductive system and secondary sex characteristics. It is mainly produced by the ovarian follicles, which are small sacs within the ovaries that contain the immature eggs. During each menstrual cycle, a follicle grows and develops under the influence of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) produced by the pituitary gland. As the follicle matures, it produces increasing amounts of estrogen until it reaches a peak level, which triggers ovulation. After ovulation, the remaining cells of the follicle form a structure called the corpus luteum, which produces both estrogen and progesterone. However, estrogen is primarily produced by the follicles.

Hormones are chemical messengers that are secreted by endocrine glands and transported through the bloodstream to target cells or organs, where they produce specific physiological responses. Hormones can affect a wide range of physiological processes, including growth and development, metabolism, reproduction, and behavior. Examples of hormones include insulin, which regulates glucose metabolism, and testosterone, which is involved in the development of male secondary sexual characteristics. Hormones are typically produced in response to specific stimuli, such as changes in blood glucose levels or the presence of a particular chemical or hormone in the body.

Insulin is a hormone secreted by the pancreas that plays a critical role in regulating blood sugar levels in the body. When we eat, the carbohydrates present in the food get broken down into glucose, which enters the bloodstream. As blood sugar levels rise, the pancreas secretes insulin, which enables the body's cells to take up glucose from the bloodstream and use it for energy. Insulin also helps to lower the amount of glucose produced by the liver. In people with diabetes, the body does not produce enough insulin or cannot use it properly, resulting in high blood sugar levels.

Acetylene gas is commonly used in the artificial ripening of green fruit. It acts as a plant hormone and triggers the fruit to ripen faster. When acetylene gas is released, it gets converted to ethylene, which then stimulates the production of enzymes that break down the cell walls and chlorophyll in the fruit, leading to ripening. However, the use of acetylene gas for fruit ripening is controversial as it can pose health hazards and affect the quality of the fruit. Therefore, some countries have banned its use, and alternative methods are being explored.