Effects of bovine growth hormone, human placental lactogen and ovine prolactin on intestinal fluid and ion transport in the rat.

The influence of bovine growth hormone and human placental lactogen on intestinal absorption was compared with that of ovine prolactin. Administration of each of these hormones in vivo daily for 2 days, resulted in increased fluid and electrolyte transport by the rat intestine, as measured in vitro. Hypophysectomy causes a fall in fluid and ion absorption in the rat jejunum but these changes are prevented by growth hormone treatment. Bovine growth hormone and ovine prolactin produce essentially similar effects in intact rats: significant increases in fluid, sodium and calcium transport in the duodenum; in fluid, sodium and potassium transport in the jejunum; in sodium, chloride, potassium and calcium transport in the ileum. Growth hormone also significantly increased fluid, sodium and chloride transport in the colon. Treatment of hypophysectomized rats with human placental lactogen enhanced fluid and ion transport in the jejunum; however, it failed to restore normal potassium transport in the ileum and colon at the 1 mg daily dose level. Growth hormone and human placental lactogen appear to affect jejunal water and electrolyte transport in the same manner as occurs with prolactin, possibly by influencing active ion transport.