Pulsatile Release
Definition
Secretion in bursts rather than at a steady level. Growth hormone and GnRH are both pulsatile, and the pattern carries information: continuous stimulation of a GnRH receptor suppresses the axis it would otherwise drive.
Terms used in this definition
Other entries this definition refers to.
What this means for research sourcing
Mechanistic terms like this describe how research compounds behave in vitro. See the mechanism overviews for compounds Volta stocks.
Related Terms in Pharmacology
IGF-1 (Insulin-Like Growth Factor 1)
A liver-produced hormone that mediates much of what growth hormone does to growth, metabolism and body composition. Serum IGF-1 is the usual laboratory proxy for growth hormone exposure because it is stable where GH itself is pulsatile.
Pituitary Gland
The gland at the base of the brain that releases growth hormone, the gonadotropins and other hormones on hypothalamic instruction. Secretagogues and releasing-hormone analogues both act here rather than at the tissue where the effect appears.
Hypothalamus
The brain region joining the nervous and endocrine systems, releasing GHRH, GnRH and somatostatin to control the pituitary. It also carries much of the appetite circuitry that incretin agonists act on.
GnRH (Gonadotropin-Releasing Hormone)
The hypothalamic hormone released in pulses that tells the pituitary to secrete luteinising hormone and follicle-stimulating hormone. Continuous rather than pulsatile stimulation of its receptor has the opposite effect and shuts those hormones down.
Luteinizing Hormone (LH)
A pituitary gonadotropin that triggers ovulation and, in males, drives testosterone production by testicular Leydig cells. HCG is used in research as an LH analogue because it acts at the same receptor with a longer half-life.
Follicle-Stimulating Hormone (FSH)
The other pituitary gonadotropin, which supports ovarian follicle development and spermatogenesis. It is released alongside LH under GnRH control, and the two are usually measured together.
Cortisol
The adrenal glucocorticoid released under stress and on a daily rhythm. It is measured in growth hormone secretagogue studies because some compounds in that class raise it transiently while others do not, and that difference is what selectivity means here.
Prolactin
A pituitary hormone best known for its role in lactation, also measured in secretagogue studies because several GHRPs raise it modestly. Ipamorelin's reputation rests largely on not doing so.