Recombinant human growth hormone (SMP-140) is effective for growth promotion in hypophysectomized rats

Comparative study of the effects of different growth hormone doses on growth and spatial performance of hypophysectomized rats

This study was designed to examine the effects of recombinant human growth hormone replacement on somatic growth and cognitive function in hypophysectomized (HYPOX) female Sprague-Dawley rats. Rats (5 per group) were randomized by weight to 3 experimental groups: group 1, administered 200 microg/kg of GH once daily for 9 days; group 2, administered 200 microg/kg of GH twice daily; and group 3, administered saline daily. Somatic growth was evaluated by measurement of body weight daily and of the width of the proximal tibial growth plate of the HYPOX rats. Cognitive function was evaluated using the Morris water maze (MWM) test. The results indicated that GH replacement therapy in HYPOX rats promoted an increase in the body weight and the width of the tibial growth plate in a dose-dependent manner. On the third day of the MWM test, the escape latency in the GH-treated groups 1 and 2 was significantly shorter than that in the control rats (P<0.001 and P=0.032, respectively), suggesting that rhGH improved spatial memory acquisition in the MWM test. Therefore it is concluded that rhGH replacement therapy in HYPOX rats stimulates an increase in somatic growth in a dose-dependent manner and also has beneficial effects on cognitive functions.

Plant-produced human growth hormone shows biological activity in a rat model

Plants have been shown to be efficient systems for expressing a wide range of recombinant proteins from various origins. Here, using a plant virus-based expression vector to produce human growth hormone (hGH) in Nicotiana benthamiana plants, we demonstrate, for the first time, that the plant-produced hGH (pphGH) is biologically active in a hypophysectomized rat model. We observed an average weight gain of approximately 17 g per animal in a group of 10 animals that were injected subcutaneously with pphGH with 60 microg/dose for 10 days. With the increasing demand for hGH, accompanied with the need to make this recombinant protein available to a wider population at a more reasonable cost, plants provide a feasible alternative to current production platforms.