Biological Pathway
HPG Axis
Last updated
The hypothalamic-pituitary-gonadal axis. The hypothalamus releases GnRH in pulses, the pituitary answers with LH and FSH, and the gonads produce testosterone or oestrogen along with sperm or eggs. Sex hormones feed back to slow the upstream signals, which is why supplying a hormone from outside tends to suppress the body's own production. Pulse pattern matters as much as amount, since steady GnRH exposure shuts the axis down rather than driving it.
Why it matters here
The feedback structure is why a record here may report a change in LH or FSH rather than in testosterone, and why those readings can move in opposite directions on the same page.
What it is not
HPG and HPTA are used interchangeably in forum writing, but HPTA names the testicular version of the axis and does not describe women. Do not read it as the HPA Axis, which is the adrenal and cortisol axis.
Also called
- hpg
- hypothalamic-pituitary-gonadal
- hpta
HPTA stands for hypothalamic-pituitary-testicular axis and is the usual term in performance-enhancement writing. It is this same axis described in male-specific terms.