Neuropeptide Y modulates growth hormone but not luteinizing hormone secretion from prepuberal gilt anterior pituitary cells in culture.
Barb. C R CR; Barrett. J B JB
Key Findings
- NPY did not alter basal LH secretion and only slightly reduced LH when combined with a low dose of GnRH.
- High concentrations of NPY (10⁻⁶ M and 10⁻⁷ M) increased basal GH secretion in pig pituitary cells.
- NPY suppressed GH release triggered by low‑dose GRF but enhanced GH release when a high dose of GRF was used.
Practical Outcomes
- For biohackers, the study hints that NPY could influence growth hormone levels, but the evidence is limited to pig cells in a dish and the doses used are far higher than anything practical for humans. There is no clear protocol or safe dosage for using NPY to boost GH in people, so it remains a basic science observation rather than an actionable supplement strategy.
Summary
In a lab study using pig pituitary cells, researchers found that the brain peptide neuropeptide‑Y (NPY) does not change the release of the reproductive hormone LH, but it can raise the amount of growth hormone (GH) that the cells release on its own. When combined with a GH‑releasing factor, low amounts of NPY actually dampened the GH boost, while a higher amount of NPY helped the GH‑releasing factor work a bit better. These effects were seen only in isolated cells, not in whole animals.
Abstract
Pituitary cells, from seven 160- to 170-day-old pigs, were studied in primary culture to determine the affects NPY on LH and GH secretion at the level of the pituitary. On day 4 of culture, medium was discarded, plates were rinsed twice with serum-free medium and cells were cultured in 1 ml fresh medium without serum and challenged individually with 10(-10), 10(-8) or 10(-6) M [Ala(15)]-h growth hormone-releasing factor-(1-29)NH(2) (GRF); 10(-9), 10(-8) or 10(-7) M GnRH or 10(-9), 10(-8), 10(-7) or 10(-6) M NPY individually or in combinations with 10(-9) or 10(-8) M GnRH or 10(-8) or 10(-6)M GRF. Cells were exposed to treatment for 4 h at which time medium was harvested and quantified for LH and GH. Basal LH secretion (control; n = 7 pituitaries) was 12 +/- 6 ng/well. Relative to control at 4 h, 10(-9), 10(-8) and 10(-7) M GnRH increased (P < 0.01) LH secretion by 169, 176 and 197%, respectively. Neuropeptide-Y did not alter (P > 0.4) basal LH secretion nor 10(-8) M GnRH-induced increase in LH secretion but 10(-9) M GnRH-stimulated LH secretion was reduced by NPY and was not different from control or GnRH alone. Basal GH secretion (control; n = 7 pituitaries) was 56 +/- 12 ng/well. Relative to control at 4 h, 10(-10), 10(-8) and 10(-6) M GRF increased GH secretion by 111%, 125% (P < 0.01) and 150% (P < 0.01), respectively. Only 10(-6) M (134%) and 10(-7) M (125%) NPY increased (P < 0.04) basal GH secretion. Addition of 10(-9), 10(-8) and 10(-7) M NPY in combination with 10(-8) M GRF suppressed (P < 0.04) GRF-stimulated GH secretion. However, 10(-9) M NPY enhanced (P < 0.06) the GH response to 10(-6) M GRF. These results demonstrate that NPY may directly modulate GH secretion at the level of the pituitary gland.
Study Information
pubmed
2005
2005-04-07T00:00:00.000Z
10.1016/j.domaniend.2005.03.004