Micrin research


Micrin is regarded as a 'health housekeeping' hormone involved in regulating development, bodily maintenance, reproduction and senescence. Corroborated pioneering research has shown that micrin-related molecules can significantly reduce tissue overgrowth affecting the heart, liver, kidneys and other visceral and endocrine organs, and retard tumour cell growth. The intention is to exploit micrin-related drug candidates in areas of unmet medical need such as cardiac hypertrophy, polycystic kidney disease and benign and malignant proliferative diseases of the prostate and breast.


Micrin preferentially targets abnormal cells. Breast tumour cells in culture are shown in the time-lapse movie. Exposed to a low dose of micrin, the cells look like they are exploding and disappearing. In fact they are committing suicide, a process known as apoptosis. First there is cellular shrinkage, then chromatin condensation, DNA fragmentation and other intracellular changes that look like density changes. Membrane blebbing follows and 'apoptotic body' formation (sealing off of cytoplasm into small discrete units). Surrounding cells engulf the apoptotic bodies, by phagocytosis, before themselves succumbing to micrin.


Micrin derivatives are used in stem cell research, notably to maintain the cells of interest in a quiescent state to facilitate research and enable them to be used in the clinic.


The company’s founding hypothesis is that the body has a reproductively associated hormonal brake against tissue overgrowth and tumours. A theoretical exposition on micrin, the body’s brake, is available here.


Micrin is an example of a polypeptide hormone, meaning that it is a short protein which like all proteins consists of a chain of the 20 different available amino acids in a specific order. Within hormone producing cells micrin is sculpted for secretion into the blood stream from a much larger precursor protein, which is thus a prohormone. You can read about the hunt for the micrin prohormone here, with additional images of tissue sections here.


We have developed minimal copies of micrin that can be taken in a glass of water, for therapeutic use in reproduction (e.g. infertility), cancer and other indications (e.g. endometriosis, PCOS, BPH).


Hart, J E: Endocrine pathology of estrogens: species differences. Pharmacology & Therapeutics, 47, 203-213, 1990

Davies KG, Hart JE: Fecundity and lifespan manipulation in Caenorhabditis elegans using exogenous peptides. Nematology, 10, 103-112, 2008

Haylor JL, Parker E, Risbridger GP, Beale D, Brown BL, Dobson PRM, Clarke IJ, Hart JE: Inhibition of compensatory renal growth by the N-terminus of a sheep-derived peptide. Regulatory Peptides, 152, 48-53, 2009

Hart JE: Proteinaceous Compounds. Patent granted to Endocrine
Pharmaceuticals 2013 (US 8367801; also EP 2234632, 2014).

Hart JE: The body has a brake: micrin is a postulated new gonadal hormone curbing tissue overgrowth and restricting reproduction. Medical Hypotheses. 83, 775–786, 2014.

Davies KG, Zimmerman B, Dudley E, Newton RP, Hart JE. Reproduction
potentiated in nematodes (Caenorhabditis elegans) and guppy fish (Poeciliareticulata) by adding a synthetic peptide to their aqueous environment.
Journal of Experimental Biology, 218, 778–785, 2015

Hart JE, Clarke IJ, Risbridger GP, Ferneyhough B, Vega-Hernández M.
Mysterious inhibitory cell regulator investigated and found likely to be
secretogranin II related. PeerJ, 5: e3833, 2017

Howlett DR, Clarke IJ, Newton RP, Hart JE. Epitope mapping of an uncertain endogenous antigen implies secretogranin II peptide splicing. F1000Research,8:1732, 2019.





Micrin time-lapse video

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