Norepinephrine inhibits rat pre-adipocyte proliferation.
Hormonal and neural status are major determinants for cellular growth. The purpose of this study was to assess the influence of the adrenergic hormones on pre-adipocyte growth in primary cell culture. Stromal-vascular cells were obtained from the inguinal pad of young rats and grown in culture for two weeks. Cells were exposed to norepinephrine (NE) during the proliferative phase of growth, labelled by [3H]-thymidine incorporation and then placed on a differentiation promoting medium. Adipocytes and stromal cells were separated using a density gradient, and [3H]-thymidine content was determined for both cell types. NE reduced [3H]-thymidine uptake indicating a reduction in pre-adipocyte proliferation. NE-induced inhibition of pre-adipocyte growth was blocked by the presence of propranolol, whereas phenoxybenzamine had no effect, thereby suggesting that NE-inhibition is through beta-adrenoceptors. Pre-adipocytes were treated with NE for varying lengths of time to investigate whether cells were desensitized to chronic beta-adrenergic stimulation. In addition, adenosine deaminase (ADA) was also applied to eliminate adenosine which may accumulate during NE stimulation. Neither the duration of NE exposure nor ADA treatment affected adrenergic control of adipocyte growth. These studies indicate that NE reduces pre-adipocyte proliferation and therefore may be an important negative regulatory component of adipocyte growth.
Jones
D D
DD
Department of Foods and Nutrition, University of Georgia, Athens 30602.
Ramsay
T G
TG
Hausman
G J
GJ
Martin
R J
RJ
D000243:Adenosine Deaminase / Q000494:pharmacology; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects*; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D009638:Norepinephrine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects
D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D000243:Adenosine Deaminase; D009638:Norepinephrine