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Mod GRF 1-29

Sermorelin, Growth Hormone Releasing Hormone (1-29), hGRF(1-29)NH2

Quick Stats
Studies 227
Trials 47
Overview Studies Clinical Trials
Score 2
1991 pubmed

Growth hormone-releasing factor (GRF) suppresses the in vitro proliferation of mammotrophs from the adult rat.

Shinkai. T T; Ooka. H H; Noumura. T T

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Key Findings

  • GRF‑1‑29 at 10⁻ÂčÂČ M suppresses proliferation of mammotrophs (prolactin cells) in vitro.
  • The same GRF‑1‑29 treatment promotes an increase in somatotroph (growth‑hormone) cell numbers.
  • The suppression of mammotroph growth is linked to mitotic inhibition, and GRF has no effect on fibroblast proliferation.

Practical Outcomes

  • For biohackers, this study suggests that GRF‑1‑29 may influence the balance between prolactin and growth hormone cells, but the findings are limited to rat cells in a dish and do not translate into clear dosing or protocols for humans. It provides a mechanistic hint rather than a direct, actionable strategy for longevity or performance.

Summary

A lab study on adult female rat pituitary cells found that adding a tiny amount of growth hormone‑releasing factor (GRF‑1‑29) stopped the growth of prolactin‑producing cells (mammotrophs) while letting growth‑hormone‑producing cells (somatotrophs) increase. The effect was seen at extremely low concentrations and didn’t affect other cell types like fibroblasts.

Abstract

In order to examine the hypothalamic control of acidophilic proliferation, anterior pituitary cells from adult female rats were cultured with or without rat growth hormone-releasing factor fragment 1-29 (GRF-29). Changes in the numbers of mammotrophs and somatotrophs during culture were measured by immunocytochemical staining. The addition of GRF suppressed the increase in the number of mammotrophs even at the very low concentration of 10(-12) M. The number of somatotrophs increased in the medium containing GRF. The increase in mammotroph number was blocked by cytosine arabinoside, a mitotic inhibitor. GRF had no effect on the in vitro proliferation of fibroblasts. These results indicate the important role of hypothalamic GRF in the differential growth and secretion of the acidophils in vivo.

Study Information

Provider

pubmed

Year

1991

Date

1991-02-11T00:00:00.000Z

DOI

10.1016/0304-3940(91)90146-k