Hormones and Water Movement Through the Vertebrate Intestine

Intestinal absorption of fluid and NaCl in rats is significantly decreased after hypophysectomy and increased in rats with pituitary implants. Oestrogen and reserpine significantly stimulate mucosal fluid and NaCl transfer in both normal and adrenalectomized rats, comparable to the effects of administration of prolactin. In intact rats, ergocryptine enhanced intestinal absorption of fluid and NaCl; however, it failed to exert any effects in adrenalectomized rats. Adrenalectomy alone had no adverse effects on intestinal absorption in saline-compensated rats. The administration of corticosterone alone or together with prolactin significantly enhanced intestinal absorption, although the effect of corticosterone alone was more variable. These data strongly suggest that increased endogenous prolactin levels produce stimulatory effects on intestinal absorption of fluid and NaCl by the rat jejunum.

Section: Resultsmentioning

confidence: 98%

Analysis of the Role of Endogenous Prolactin on Fluid and Sodium Chloride Absorption by the Rat Jejunum

Mainoya¹

1975

“…Aldosterone stimulates mucosal transfer of water and sodium in the rat small intestine (Crocker & Munday, 1969) and absorption of sodium by the rat colon (Edmonds, 1972). The effects of aldosterone on the proximal small intestine are not always easy to demonstrate without prior suppression of endogenous aldo¬ sterone levels (Matty & Noble, 1972). Angiotensin also stimulates fluid and sodium transport by the jejunum of rats sensitized by previous adrenalectomy and nephrectomy (Crocker & Munday, 1970).…”

Section: Resultsmentioning

confidence: 99%

“…Although recent reviews of hormonal influences on intestinal absorption and metabolic functions emphasize the importance of effects on water and electrolyte absorption by the mammalian gut (Gelb & Gerson, 1969;Levin, 1969;Matty & Noble, 1972), the adenohypophysial hormones have not received much attention in this context. Prolactin (PRL) is known to decrease intestinal ion and water permeability in seawater eels (Utida, Hirano, Oide, Ando, Johnson & Bern, 1972;Utida & Hirano, 1973).…”

Section: Introductionmentioning

confidence: 99%

Influence of Ovine Prolactin on Transport of Fluid and Sodium Chloride by the Mammalian Intestine and Gall Bladder

Mainoya

Bern

Regan

1974

Mucosal fluid, sodium and chloride transfer were measured in everted sacs of rat, guinea-pig and hamster jejunum, and in rat ileum and colon, and in guinea-pig gall bladder. After treatment of the animal with ovine prolactin, a highly significant enhancement of fluid and NaCl absorption was observed in rat, hamster and guinea-pig jejunum. Prolactin treatment caused a significant increase in fluid and NaCl transfer in rat ileum, but not in gui nea\x=req-\ pig ileum or rat colon. Prolactin administration had no consistent effect on fluid and NaCl absorption by the guinea-pig gall bladder. The several regions of the mammalian gut appear to differ in their responsiveness to prolactin.

“…There is considerable evidence implicating the action of several hormones on intestinal absorption of water and electrolytes (Gelb & Gerson, 1969;Levin, 1969;Matty & Noble, 1972). Recently, we have demonstrated that pituitary and placental lactogenic hormones caused dramatic increases in mucosal fluid and ion transport by the rat intestine (Ramsey & Bern, 1972;Mainoya, Bern & Regan, 1974;Mainoya, 1975e).…”

Section: Introductionmentioning

confidence: 98%

“…Matty & Noble, 1972), but there appears to have been no investigation of the effects of pregnancy and lactation on intestinal fluid and NaCl transport. In view of the important increases in serum levels of prolactin during oestrus, pregnancy and lactation (Amenomori, Chen & Meites, 1970), the present investigation of the ability of the rat jejunum to transport fluid and electrolytes during these various physiological states was undertaken.…”

Section: Introductionmentioning

confidence: 99%

Influence of Reproductive State on Intestinal Fluid and Ion Transport by the Rat Jejunum, in Relation to the Possible Contribution of Prolactin

Mainoya¹

1975

Mucosal fluid, sodium and chloride transfer by the rat jejunum was higher at pro-oestrus and oestrus than at dioestrus. Prolactin enhanced intestinal absorption in dioestrous but not in oestrous rats. Ovariectomy had no significant effect on fluid and sodium absorption but resulted in increased chloride absorption. Oestrogen treatment, however, stimulated fluid and sodium transport without affecting chloride absorption in ovariectomized rats. In contrast, progesterone had no influence on fluid and sodium transport but inhibited chloride absorption. Intestinal absorption of fluid, sodium chloride, potassium, calcium and magnesium was significantly increased during pregnancy and lactation. The limited effect of 2-Br-alpha-ergocryptine in depressing intestinal absorption of fluid and NaCl in both pregnant and lactating rats suggests that hormones other than prolactin are also involved. Lactating rats not suckled for 24 h, or subjected to reduction in the number of pups from eight to three, did not show major changes in intestinal absorption of fluid and NaCl. The present data suggest that increases in intestinal transport during oestrus, pregnancy and lactation are attributable to hormonal changes to which prolactin may make an important contribution.