TY - JOUR
T1 - Hormonal effects on l-proline transport in Coho Salmon
AU - Collie, Nathan L.
AU - Stevens, Jacqueline J.
N1 - Funding Information:
We wish to express thanks to Dr. H. A. Bern for his support and advice throughout this project; to N. H. Richman for considerable help in the experiments; to Dr. G. Young for assaying plasma cortisol; and to Jacky Vittori for much clerical assistance. This study represents a portion of a dissertation submitted by N.L.C. in partial fulfillment of the requirements for the Ph.D. degree in zoology. Financial support was provided by MARC (Minority Access to Research Careers) UC Berkeley summer program to J.S; by NOAA, National Sea Grant College Program, Department of Commerce, Grant NA80AA-D-00120, Project R/F-78; by a traineeship to N.L.C. through the California Sea Grant College Program; and by NSF Grant PCM 81-10111 to H. A. Bern. The US Government is authorized to produce and distribute reprints for governmental purposes notwithstanding any copyright notation that may appear hereon.
PY - 1985/9
Y1 - 1985/9
N2 - The hormonal control of proline transport in pyloric ceca was studied in regard to the effects of cortisol, growth hormone (GH), epinephrine, and 3-isobutyl-1-methylxanthine (IBMX). Cortisol pellets implantted in yearling freshwater (FW) salmon for 2 weeks elevated plasma cortisol levels in six times above that of control fish. The maximal influx (Jmax) and the half-saturation constant (Kt) of proline influx were twofold greater in cortisol-treated fish than the values in controls; the apparent passive permeability coefficient (Pa) was significantly reduced in the former group. FW salmon implanted with GH for 2 weeks showed increased body weight gain and a higher Jmax of proline influx compared with that of control fish. GH treatment resulted in a higher Pa of proline influx as well as in a 30% increase in area-specific intestinal dry weight. Thus, GH and cortisol may play a regulatory role in intestinal amino acid absorption during salmon development. The in vitro effects of epinephrine and the phosphodiesterase inhibitor, IBMX, on short-circuit current (Isc) and proline influx in salmon intestine were examined. Epinephrine (10-6 M) caused a rapid increase in negative Isc (mucosa, ground). Pyloric ceca preincubated with epinephrine for 30 min showed reduced total proline influx compared with influx in paired control tissues. Epinephrine increased and IBMX decreased the Kt of proline influx; IBMX also reduced Jmax. The possible interaction between the effects of epinephrine and IBMX on ion transport and Na+-coupled proline influx are discussed.
AB - The hormonal control of proline transport in pyloric ceca was studied in regard to the effects of cortisol, growth hormone (GH), epinephrine, and 3-isobutyl-1-methylxanthine (IBMX). Cortisol pellets implantted in yearling freshwater (FW) salmon for 2 weeks elevated plasma cortisol levels in six times above that of control fish. The maximal influx (Jmax) and the half-saturation constant (Kt) of proline influx were twofold greater in cortisol-treated fish than the values in controls; the apparent passive permeability coefficient (Pa) was significantly reduced in the former group. FW salmon implanted with GH for 2 weeks showed increased body weight gain and a higher Jmax of proline influx compared with that of control fish. GH treatment resulted in a higher Pa of proline influx as well as in a 30% increase in area-specific intestinal dry weight. Thus, GH and cortisol may play a regulatory role in intestinal amino acid absorption during salmon development. The in vitro effects of epinephrine and the phosphodiesterase inhibitor, IBMX, on short-circuit current (Isc) and proline influx in salmon intestine were examined. Epinephrine (10-6 M) caused a rapid increase in negative Isc (mucosa, ground). Pyloric ceca preincubated with epinephrine for 30 min showed reduced total proline influx compared with influx in paired control tissues. Epinephrine increased and IBMX decreased the Kt of proline influx; IBMX also reduced Jmax. The possible interaction between the effects of epinephrine and IBMX on ion transport and Na+-coupled proline influx are discussed.
UR - http://www.scopus.com/inward/record.url?scp=0021857454&partnerID=8YFLogxK
U2 - 10.1016/0016-6480(85)90397-1
DO - 10.1016/0016-6480(85)90397-1
M3 - Article
C2 - 2412938
AN - SCOPUS:0021857454
SN - 0016-6480
VL - 59
SP - 399
EP - 409
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 3
ER -