Hormones are organic substances secreted by certain specialized cells (glands) in the body, which are diffused or transported to some other part of the body and bring about certain changes. A number of hormones are directly or indirectly involved in vaarious aspects of reproduction. The secretion of these hormones is essential for the maintenance of a proper internal environment to ensure successful reproduction. The hormones involved in reproduction may be divided into two groups:
(a) Primary hormones of reproduction
(b) Secondary hormones of reproduction
(a) Primary hormones of reproduction:
Gland | Hormone | Important Function |
|---|---|---|
Anterior Pituitary | Follicle stimulating hormone (FSH) | Spermatogenesis; ovarian follicular growth. |
Lutenizing hormone (LH) (ICSH) | Androgen release; ovulation. | |
Posterior Pituitary | Oxytocin | Parturition; uterine contractions; milk letdown. |
Testis | Testosterone | Maintenance of male reproductive duct system and secondary sexual characteristics; male sexual behavior; spermatogenesis |
Ovary | Estradiol | Maintenance of female reproductive duct system and secondary sexual behavior; mammary gland stimulation. |
Progestrone | Implantation; pregnancy maintenance; mammary gland stimulation. | |
Relaxin | Relaxation of uterine cervix and pubic symphysis; inhibition of uterine contractions. | |
Placenta | Human chorionicgonadotrophin (HCG [primate]) | LH-Like |
Pregnant mare's serum (PMS [horse]) | FSH-Like |
(b) Secondary hormones of reproduction:
Gland | Hormone | Important Function |
|---|---|---|
Anterior Pituitary | Somatotropin releasing hormone (STH) | Body growth; protein synthesis. |
Thyroid stimulating hormone (TSH) | Stimulation of thyroid gland; thyroxine release and iodine uptake by thyroid. | |
Adrenocorticotropic hormone (ACTH) | Stimulation of adrenal cortex; release of adrenal corticoids | |
Posterior Pituitary | Vasopressin (antidiuretic horomne) (ADR) | Water balance. |
Thyroid | Thyroxine | Body growth; development of maturation; oxidation of feeds. |
Adrenal Cortex | Aldosterone | Electrolyte and water metabolism. |
17-OH corticoids (cortisone) (cortisol) (corticosterone) | Carbohydrate, protein, and fat metabolism. | |
Pancreas | Insulin | Carbohydrate, fat, and protein metabolism. |
Parathyroid | Parathormone | Calcium and Phosphorus metabolism. |
The primary hormones are directly involved in various aspects of reproduction, such as spermatogenesis, oogenesis, and ovulation. The secondary hormones are needed for the normal functioning of the organisms which makes it possible for reproduction to occur.
