Estradiol and testosterone levels in patients undergoing partial hepatectomy - A possible signal for hepatic regeneration?

In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection. © 1989 Plenum Publishing Corporation

Changes in adenylate cyclase and phosphodiesterase activities during the growth cycle of adult rat hepatocytes in primary culture

Long-term primary adult rat hepatocyte cultures show growth-state-dependent changes in adenylate cyclase and cAMP phosphodiesterase activities. Cellular adenylate cyclase activity decreases to undetectable levels within 1 day postplating, reappears on Days 4–5, and becomes maximal on Day 9. Membrane adenylate cyclase and cellular cAMP formation are insensitive to glucagon during log phase (Days 4–8) but not during lag (Day 1) or stationary phase (Day 12). Cyclic AMP phosphodiesterase activities (soluble and particulate) fall ∼-70% by Day 2 but recover as proliferation begins. By contrast, the particulate phosphodiesterase assayed at 100 μm cAMP, decreased during Days 0–2. These observations simulate changes seen during liver proliferative transitions in vivo and, therefore, further support the use of these cultures as a developmental model.link_to_subscribed_fulltex