Effects of glucocorticoids on cartilage growth and response to IGF-I in the tilapia (Oreochromis mossambicus).

Abstract:

:To study the effects of glucocorticoids and IGF-I on the modulation of growth in the tilapia Oreochromis mossambicus, we employed an epiceratobranchial cartilage radioisotope incorporation assay, wherein radiolabeled sulfate and thymidine uptakes are measured in vitro to indicate proteoglycan synthesis and cell proliferation, respectively. Cartilage explants were cultured with cortisol or dexamethasone with or without recombinant bovine insulin-like growth factor-I. Cortisol directly inhibited sulfate uptake at 100 and 1000 ng/mL concentrations in a concentration-dependent manner but inhibited thymidine uptake significantly only at the 1000 ng/mL concentration. Dexamethasone inhibited sulfate and thymidine uptake at concentrations similar to the effective concentrations of cortisol. Cortisol did not inhibit IGF-I stimulation of sulfate uptake at any of the concentrations tested. Furthermore, cortisol did not inhibit thymidine uptake when IGF-I was present in the medium. Cortisol appears to act directly on cartilage and not by interacting with the IGF-I system. However, the physiologically significant role of cortisol is mainly an inhibitory one on cartilage metabolism. The data generally indicate an inhibitory role for glucocorticoids on cartilage growth but an inability to counter the stimulation of sulfate uptake by IGF-I.

journal_name

Gen Comp Endocrinol

authors

Datuin JP,Ng KP,Hayes TB,Bern HA

doi

10.1006/gcen.2000.7599

keywords:

subject

Has Abstract

pub_date

2001-03-01 00:00:00

pages

289-94

issue

3

eissn

0016-6480

issn

1095-6840

pii

S0016-6480(00)97599-3

journal_volume

121

pub_type

杂志文章