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The gonads—the male testes and female ovaries—produce steroid hormones. The testes produce androgens, testosterone being the most prominent, which allow for the development of secondary sex characteristics and the production of sperm cells. The ovaries produce estradiol and progesterone, which cause secondary sex characteristics and prepare the body for childbirth.
| Endocrine Glands and their Associated Hormones | ||
|---|---|---|
| Endocrine Gland | Associated Hormones | Effect |
| Hypothalamus | releasing and inhibiting hormones | regulate hormone release from pituitary gland; produce oxytocin; produce uterine contractions and milk secretion in females |
| antidiuretic hormone (ADH) | water reabsorption from kidneys; vasoconstriction to increase blood pressure | |
| Pituitary (Anterior) | growth hormone (GH) | promotes growth of body tissues, protein synthesis; metabolic functions |
| prolactin (PRL) | promotes milk production | |
| thyroid stimulating hormone (TSH) | stimulates thyroid hormone release | |
| adrenocorticotropic hormone (ACTH) | stimulates hormone release by adrenal cortex, glucocorticoids | |
| follicle-stimulating hormone (FSH) | stimulates gamete production (both ova and sperm); secretion of estradiol | |
| luteinizing hormone (LH) | stimulates androgen production by gonads; ovulation, secretion of progesterone | |
| melanocyte-stimulating hormone (MSH) | stimulates melanocytes of the skin increasing melanin pigment production. | |
| Pituitary (Posterior) | antidiuretic hormone (ADH) | stimulates water reabsorption by kidneys |
| oxytocin | stimulates uterine contractions during childbirth; milk ejection; stimulates ductus deferens and prostate gland contraction during emission | |
| Thyroid | thyroxine, triiodothyronine | stimulate and maintain metabolism; growth and development |
| calcitonin | reduces blood Ca 2+ levels | |
| Parathyroid | parathyroid hormone (PTH) | increases blood Ca 2+ levels |
| Adrenal (Cortex) | aldosterone | increases blood Na + levels; increase K + secretion |
| cortisol, corticosterone, cortisone | increase blood glucose levels; anti-inflammatory effects | |
| Adrenal (Medulla) | epinephrine, norepinephrine | stimulate fight-or-flight response; increase blood gluclose levels; increase metabolic activities |
| Pancreas | insulin | reduces blood glucose levels |
| glucagon | increases blood glucose levels | |
| Pineal gland | melatonin | regulates some biological rhythms and protects CNS from free radicals |
| Testes | androgens | regulate, promote, increase or maintain sperm production; male secondary sexual characteristics |
| Ovaries | estrogen | promotes uterine lining growth; female secondary sexual characteristics |
| progestins | promote and maintain uterine lining growth |
There are several organs whose primary functions are non-endocrine but that also possess endocrine functions. These include the heart, kidneys, intestines, thymus, gonads, and adipose tissue.
The heart possesses endocrine cells in the walls of the atria that are specialized cardiac muscle cells. These cells release the hormone atrial natriuretic peptide (ANP) in response to increased blood volume. High blood volume causes the cells to be stretched, resulting in hormone release. ANP acts on the kidneys to reduce the reabsorption of Na + , causing Na + and water to be excreted in the urine. ANP also reduces the amounts of renin released by the kidneys and aldosterone released by the adrenal cortex, further preventing the retention of water. In this way, ANP causes a reduction in blood volume and blood pressure, and reduces the concentration of Na + in the blood.
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