Abstract: Growth hormone (GH) deficiency causes decreased bone mineral density and osteoporosis, predisposing to fractures. We investigated the mechanism of action of GH on bone modeling and remodeling in hypophysectomized (HX) female rats. Thirty female Sprague–Dawley rats at age 2 months were divided into three groups with 10 rats each: control (CON) group, HX group, and HX ? GH (3 mg/kg daily SC) group, for a 4-week study. Hypophysectomy resulted in cessation of bone growth and decrease in cancellous bone mass. Periosteal bone formation decreased and bone turnover rate of endocortical and trabecular surfaces increased as compared to the CON group. GH administration for 4 weeks restored weight gain and bone growth and mitigated decrease in bone density after hypophysectomy. However, trabecular bone mass in the proximal tibial metaphysis remained.
lower in group HX ? GH than in group CON. Dynamic histomorphometric analysis showed that bone modeling of periosteal bone formation and growth plate elongation was significantly higher in group HX ? GH than in group HX. New bone formed beneath the growth plate was predominately woven bone in group CON and group HX ? GH. Bone remodeling and modeling–remodeling mixed modes in the endocortical and PTM sites were enhanced by GH administration; both bone formation and resorption activities were significantly higher than in group HX. In conclusion, GH administration to HX rats reactivated modeling activities in modeling predominant sites and increased new bone formation. GH administration also increases remodeling activities in remodeling predominant sites, giving limited net gain in the bone mass. For more information visit - http://www.lysetteiglesiasmd.com
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About Dr. Lysette Iglesias:
Dr. Lysette Iglesias was born in Havana, Cuba, on May 21st, 1975. She began studying medicine at the age of 17 at the School of Medicine of the University of Havana. She continued her medical education at the Autonomous University of Central America in San Jose, Costa Rica, from where she graduated Summa Cum Laude with a degree in medicine in January of 2000.
Dr. Lysette Iglesia completed her residency as a Pediatrician in Flushing Hospital Medical Center, in Flushing, New York. Following a Pediatric Endocrinology Fellowship at Winthrop University Hospital in Mineola, New York, she relocated to Miami, Florida, where she established a private practice in her specialty of Pediatric Endocrinology; her practice is currently associated with Miami Children's Hospital.
Dr. Lysette Iglesia is licensed to practice medicine in both New York and Florida, as well as in Costa Rica.
Dr. Lysette Iglesia holds the following professional associations:
American Medical Association – Member
American Association of Clinical Endocrinologists – Member
European Society for Pediatric Endocrinology – Member
Lawson Wilkins Pediatric Endocrinology Society – Associate Member
Medical College of Doctors and Surgeons, San Jose, Costa Rica – Member
The Endocrine Society – Member
Dr. Lysette Iglesia is a human rights activist, as well as an accomplished writer in multiple languages, who nurtures the habit of constant study to stay current with the most recent developments in her field. In her spare time, Dr. Lysette Iglesias provides pro bono care and is involved with various charitable organizations.
