Glucocorticoids and inhibition of bone formation induced by skeletal unloading

Journal Article · Thu Dec 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6289484

Halloran, B P; Bikle, D D; Cone, C M; Morey-Holton, E ^[1]

---

1. Univ. of California, San Francisco (USA) Veterans Administration Medical Center, San Francisco, CA (USA) NASA-Ames Research Center, Moffett Field, CA (USA)

Skeletal unloading or loss of normal weight bearing in the growing animal inhibits bone formation and reduces bone calcium. To determine whether the inhibition of bone formation induced by skeletal unloading is a consequence of an increase in plasma glucocorticoids and/or an increase in bone sensitivity to glucocorticoids, the authors measured plasma corticosterone throughout the day in unloaded and normally loaded rats (hindlimb elevation model) and examined the effect of adrenalectomy on the response of bone to skeletal unloading. Plasma corticosterone levels were similar in normally loaded and unloaded rats at all times. Skeletal unloading in sham-adrenalectomized animals reduced tibial and vertebral calcium by 11.5 and 11.1%, respectively, and in adrenalectomized animals by 15.3 and 20.3%, respectively. Uptake of {sup 45}Ca and ({sup 3}H)proline in the tibia was reduced by 8 and 14%, respectively, in the sham-adrenalectomized animals and by 13 and 19% in the adrenalectomized animals. Bone formation and apposition rates were reduced to the same level in sham- and adrenalectomized animals. These results suggest that the inhibition of bone formation induced by skeletal unloading is not a consequence of increased plasma glucocorticoids or an increase in bone sensitivity to the glucocorticoids but, rather, point to a local mediator in bone that senses mechanical load and transmits that information to the bone-forming cells directly.

• OSTI ID: 6289484
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:6; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ADRENALECTOMY
ALKALINE EARTH ISOTOPES
AMINES
AMINO ACIDS
ANIMAL TISSUES
AZOLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
BONE TISSUES
CALCIUM 45
CALCIUM ISOTOPES
CARBOXYLIC ACIDS
CONNECTIVE TISSUE
CORTICOSTEROIDS
CORTICOSTERONE
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
GLUCOCORTICOIDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPES
KETONES
MEDICINE
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PREGNANES
PROLINE
PYRROLES
PYRROLIDINES
RADIOISOTOPES
SKELETON
STEROIDS
SURGERY
TIBIA
TISSUES
TRITIUM COMPOUNDS
UPTAKE
VERTEBRAE