Page 77 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
3- Amine hormones

a. thyroid hormones b. Catecholamines.
Biologically similar to steroid hormones. Biologically similar to

Except: Thyroid hormones have the unique protein/peptide hormones.
property of being stored extracellularly in the
thyroid gland as part of the thyroglobulin molecule.

Mechanisms of hormone action

1- Protein/peptide hormones & 2- Steroid hormones & thyroid hormones
Catecholamines

Regulation of hormone (self-regulating)

Positive feedback Negative feedback

effect of a is A hormone ➔ released in response to a specific stimulus ➔
amplification of the (Hormone effect antagonize the effect of its stimulus)

stimulus ➔ ↑ release action reverses or negates the stimulus through negative feedback
of the hormone until a mechanism.
particular process is
complete and the  This may be controlled either

stimulus ceases,

e.g., release of Indirectly through the release of hormones by the hypothalamus
oxytocin during labor and the anterior pituitary gland ➔ e.g., steroid, and

thyroid hormones,

Directly  by blood levels of the stimulus ➔ , e.g. insulin

and glucagon

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