What is the hypothalamus pituitary gonadal axis?
The HPG axis is a major signaling pathway controlling gonadal sex change in fish. Unlike other vertebrates, gonadotropin releasing hormone (GnRH) neurons located in the preoptic area of the hypothalamus directly innervate the anterior pituitary in fish.
What stimulates the hypothalamic-pituitary-gonadal axis?
Relaxin-3 stimulates the hypothalamic-pituitary-gonadal axis.
What order of feedback loop is the hypothalamic-pituitary-gonadal axis?
The HPG axis is controlled by a negative feedback loop. In the healthy brain, the hypothalamus releases gonadotropin-releasing hormone (GnRH) into the median eminence, and then GnRH is transported via the hypophyseal portal system to the anterior pituitary where it acts on its receptor (GnRHR).
What is the HPGL axis?
The hypothalamic–pituitary–gonadal axis (HPG axis) refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity.
What is the gonadal axis?
The gonadal axis involves a complex interaction between the hypothalamus, pituitary gland and the gonads. This axis helps to regulate development, reproduction, ageing and many other key physiological processes.
What do the gonads secrete?
The gonads, the primary reproductive organs, are the testes in the male and the ovaries in the female. These organs are responsible for producing the sperm and ova, but they also secrete hormones and are considered to be endocrine glands.
What does gonadal mean?
: a reproductive gland (such as an ovary or testis) that produces gametes.
How the hypothalamus controls the pituitary gland?
The hypothalamus links the nervous and endocrine systems by way of the pituitary gland. Specialized neuron clusters called neurosecretory cells in the hypothalamus produce the hormones Antidiuretic Hormone (ADH) and Oxytocin (OXT), and transport them to the pituitary, where they’re stored for later release.
How does the hypothalamus control the anterior pituitary?
The hypothalamus controls the anterior pituitary functions by means of peptide hormones secreted, on signal, into the portal blood system that connects them. The peptides either stimulate or inhibit the release of the stored pituitary hormone, apparently, via their interaction with extracellular membrane receptors.
What do gonadal hormones do?
Gonadal hormones are crucial for the pubertal growth spurt, and estrogen is necessary for epiphyseal closure. In addition, gonadal steroids contribute to skeletal gender differences. Men exhibit larger bones due to androgen stimulation of periosteal formation, whereas estrogen has an inhibitory effect.
What is the function of the hypothalamic pituitary-gonadal axis?
The hypothalamic-pituitary-gonadal (HPG) axis, which governs the reproductive system, is driven by the brain. Gonadotropin (FSH and LH) secretion by the anterior pituitary gland is controlled by the hypothalamus through the release of GnRH.
Is hyperprolactinemia a cause of secondary osteoporosis?
Hyperprolactinemia is a recognized cause of secondary osteopo … The incidence of hyperprolactinemia in women peaks during the 3rd-4th decade and then greatly decreases after the menopause. Apart from the effects on the hypothalamic-pituitary-gonadal axis, prolactin can act directly on bone metabolism.
How effective are dopamine agonists in the treatment of prolactinomas?
Although relatively rare, prolactinomas can be observed in post-menopausal women and are frequently large and invasive; dopamine agonists appear to be as effective in these patients as in younger women to induce reduction of prolactin levels and tumour shrinkage.
What is the incidence of hyperprolactinemia?
The incidence of hyperprolactinemia in women peaks during the 3rd-4th decade and then greatly decreases after the menopause. Apart from the effects on the hypothalamic-pituitary-gonadal axis, prolactin can act directly on bone metabolism.