A gonadotroph is a hormone-producing biological cell of the anterior pituitary that synthesizes the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone. These products act on the gonads. Its upstream stimulus, gonadotropin-releasing hormone (GnRH), is made by hypothalamic neurons and delivered through the hypophyseal portal system. The incoming signal and the gonadotroph's secreted products are distinct hormones.[ref]
Anatomy and Physiology 2e by J. Gordon Betts and others. Section17.3: anterior-pituitary regulation; Follicle-Stimulating Hormone and Luteinizing Hormone
A gonadotroph responds to a time-varying input, rather than merely counting the total amount of GnRH delivered. In a 1985 experiment, investigators surgically separated the pituitary from hypothalamic control in sheep and supplied equal-sized GnRH pulses hourly or every two hours. The less frequent schedule produced larger individual LH responses. This demonstrates that pulse timing can change the gland's output; it does not imply that doubling the interval doubles every response in every animal.[ref]
GnRH pulse frequency determines LH pulse amplitude by altering the amount of releasable LH in the pituitary glands of ewes by Iain J. Clarke and James T. Cummins. Summary: disconnected pituitaries,250ng pulses and LH-response comparison
For an experimental interpretation, distinguish pulse amplitude, interval and daily dose. Keeping the amount per pulse fixed while halving pulse frequency also halves daily input. Measuring the gland's LH output tests a physiological response of its secretory cells, but does not by itself identify every intracellular step of the response.
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