IGF-1 LR3

Mechanism (as reported)

Across the provided sources, mechanistic findings include reported effects on insulin secretion dynamics, and in vitro evidence that LR3-IGF-1 acutely stimulates Na+ transport across rumen epithelium mediated by Na+-H+ exchange (NHE). PMIDs: 37114757, 39679943, 22227200.

Key findings (each cites a source)

• A study reported recombinant expression of human IGF-1 and long R3 IGF-1 (LR3 IGF-1) in the Pichia pastoris system using fusion with xylanase XynCDBFV, with reported production of bioactive purified proteins and higher heterologous expression via bioreactor fermentation. [PMID 37261455]
• A fetal sheep study reported that a 1-week IGF-1 LR3 treatment administered to growth-restricted fetuses did not improve fetal growth outcomes and did not attenuate circulating insulin concentrations or fetal glucose-stimulated insulin secretion (GSIS), while reporting decreased circulating amino acids in the LR3 group. [PMID 39679943]
• A follow-up fetal sheep study investigated an acute exposure window and reported that glucose-stimulated insulin secretion was reduced in vivo with an IGF-1 LR3 infusion, but insulin secretion from isolated fetal islets did not differ based on infusion condition at the time of islet collection. [PMID 37114757]
• A study reported that infusion of an ovine (sheep) recombinant IGF-1 promoted organ-specific growth in fetal sheep, including increased organ growth of several listed organs and stimulated skeletal muscle myoblast proliferation (this source compares the broader concept of IGF-1 analog effects and addresses limitations with LR3 IGF-1). [PMID 36091374]
• A study in near-term fetal sheep reported that IGF-1 (LR3) treatment was associated with preserved coronary conductance per gram basis and that relationships between coronary flow and blood oxygen content were similar between IGF-1-treated and control groups, concluding that myocardial growth accompanied appropriate coronary vasculature expansion and function. [PMID 32573852]
• A study reported that in vitro exposure of hay-fed sheep rumen epithelium to serosally applied LR3-IGF-1 acutely stimulated mucosal-to-serosal Na+ flux and net Na+ flux, with inhibition by amiloride and additional findings indicating increased pH(i) recovery rate consistent with increased Na+-H+ exchange activity. [PMID 22227200]
• A study reported that a 1-week infusion of LR3 IGF-1 into late gestation fetal sheep increased the weight of some fetal organs but did not show statistically different fetal weights overall, and reported similar uterine/umbilical blood flow and similar umbilical uptake rates for glucose, lactate, and oxygen, while reporting lower umbilical amino acid uptake rates and lower fetal concentrations of multiple amino acids. [PMID 33427051]
• A study reported a decellularized plant-based nerve conduit with controlled IGF-1 LR3 release, reporting improved axonal regeneration and comparable performance to autologous nerve grafts in a rat sciatic nerve defect model, and stated that the conduit did not induce systemic toxicity. [PMID 41015370]