Final answer:
Hormones differ in their synthesis, storage, and mechanism of action based on their type. The six anterior pituitary hormones are regulated via negative feedback mechanisms. Long-loop negative feedback involves multiple endocrine glands, differing from the regulation of insulin and PTH, which are directly responsive to blood levels of substances.
Step-by-step explanation:
Comparison of Hormones: Synthesis, Storage, Transport, and Cellular Mechanisms
The synthesis, storage transport of location of receptors, and cellular mechanism of hormones differ based on their classification:
- Catecholamine hormones - synthesized in the adrenal medulla, stored in vesicles, and released into the bloodstream, acting through membrane receptors to start second messenger pathways.
- Thyroid hormones - synthesized in the thyroid gland, transported in the bloodstream bound to proteins, and act on nuclear receptors affecting gene transcription.
- Peptide hormones - synthesized and stored in endocrine cells, released upon stimulation, and act through membrane receptors to activate second messenger systems.
- Steroid hormones - synthesized in the adrenal cortex and gonads, released into the bloodstream, bound to carrier proteins, and act through intracellular receptors impacting gene expression.
The Six Anterior Pituitary Hormones
The six anterior pituitary hormones include the following:
- Growth Hormone (GH)
- Prolactin (PRL)
- Thyroid-Stimulating Hormone (TSH)
- Adrenocorticotropic Hormone (ACTH)
- Follicle-Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
Each of these hormones has specific target cells and is regulated by releasing and inhibiting hormones from the hypothalamus, following negative feedback mechanisms to control their secretion.
Long-Loop Negative Feedback
The long-loop negative feedback for the anterior pituitary hormones regulates hormone levels between the hypothalamus, anterior pituitary, and target glands. In contrast, for hormones like insulin and parathyroid hormone (PTH), feedback is directly related to blood glucose levels and calcium levels, respectively.