Linear and Skeletal growth (Primary action). rHGH acts through specific growth hormone receptors which are present in chondrocytes, osteobalsts, hepatocytes, adiocytes and fibrolblasts. These receptors are also found in other tissues such as the brain and gastrointestinal track where the role of growth hormone is not clear.
Growth Hormone stimulates skeletal and soft tissue growth by promoting cell division, amino acids uptake and protein synthesis. Its actions are predominantly mediated by hepatitis and peripheral insulin-like growth factor-1 (IGF-1) production. This results in:
• Skeletal growth in pediatric patients with growth hormone deficiency by its effect on the epiphyseal growth plates of long bones. There is an increasing growth rate and IGF-1 levels similar to that seen with human growth hormone.
• Increase in the number and size of muscle cells.
• Increase in internal organ size and red cell mass.
• Increased cellular protein synthesis due to nitrogen retention leading to a positive nitrogen balance as demonstrated by decline in urinary nitrogen excretion and blood urea nitrogen (BUN).

Carbohydrate metabolism. Genheal™ actions are predominantly mediated by hepatic and peripheral insulin-like growth factor-1 (IGF-1) production leading to immediate but brief insulin-like actions followed by more significant anti-insulin-like effects which include decreased glucose utilization (hyperglycemia) and lipolysis within 2-4 hours.

Large dose of rHGH may impair glucose tolerance and induce insulin resistance. The exact mechanism is not known. Children with hypopituitarism sometimes experience fasting hypoglycemia that is improved by growth hormone therapy.
In short children who are not growth hormone-deficient, rHGH may provoke hyperinsulinemia without impairment of glucose tolerance.
Lipid metabolism. Growth hormone administration causes reduction of body fat stores mobilization of lipid stores and increase in plasma fatty acids secondary to rHGH anti-insulin-like effect. The lipolytic effect is seen in growth hormone deficient children during the early months of treatment as loss of subcutaneous fat.
Mean cholesterol levels are decreased in patients given growth hormone.
Mineral metabolism. Genheal™ induces sodium, potassium and phosphates retention which is thought to be caused by cell growth.
Serum inorganic phosphate increase in growth-hormone deficient patients after rHGH administration. This is attributed to metabolic activity associated with bones growth and an increase tubular reabsorbing of phosphate by kidneys.
Serum calcium is not significant affected. Urinary calcium excretion increases but there is a simultaneous increase in its absorption from the intestine.
Connective tissue metabolism. Genheal™ stimulates the synthesis of chondroitin sulfate and collagen as well as the urinary excretion of hydroxiproline.