To investigate the cellular mechanisms of somatotropin (ST) action on adipose tissue lipolysis, experiments were conducted using adipose tissue taken from lactating cows treated with excipient or ST (40 mg/day). Stimulation of lipolysis in vitro by the effectors isoproterenol with or without adenosine deaminase, dibutyryl cAMP with or without isobutylmethylxanthine, and forskolin was not altered by ST treatment. Conversely, the response to the antilipolytic effector, phenylisopropyladenosine (PIA), was significantly reduced in adipose tissue explants from ST or fasted cows. The different responses to adrenergic-stimulating agents (in vivo) and PIA (in vitro) were not due to differences in the abundance of α, β or γ subunits of the stimulatory (Gs) and inhibitory (Gi) subunits of the heterotrimeric G-proteins which bind to the β-adrenergic and adenosine receptors respectively. However, the functionality of Gi proteins, as assessed by their ability to be ADP-ribosylated by pertussis toxin, was significantly reduced in ST-treated but not fasted cows. These data highlight differential regulation of signaling proteins by ST and fasting, both of which result in enhanced in vivo response to adrenergic stimulation of lipolysis.
Journal of Endocrinology (1997) 152, 465–475
Journal of Endocrinology is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
| Sept 2018 onwards | Past Year | Past 30 Days | |
|---|---|---|---|
| Full Text Views | 4 | 1 | 0 |
| PDF Downloads | 4 | 2 | 0 |
Online ISSN: 1479-6805
Print ISSN: 0022-0795
Strengthening biomedical communities
to advance science and health
CONTACT US
Bioscientifica Ltd | Starling House | 1600 Bristol Parkway North | Bristol BS34 8YU | UK
Bioscientifica Ltd | Registered in England no 3190519
